08d0ce30e0
2415 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
e8069f5a8e |
ARM64:
* Eager page splitting optimization for dirty logging, optionally
allowing for a VM to avoid the cost of hugepage splitting in the stage-2
fault path.
* Arm FF-A proxy for pKVM, allowing a pKVM host to safely interact with
services that live in the Secure world. pKVM intervenes on FF-A calls
to guarantee the host doesn't misuse memory donated to the hyp or a
pKVM guest.
* Support for running the split hypervisor with VHE enabled, known as
'hVHE' mode. This is extremely useful for testing the split
hypervisor on VHE-only systems, and paves the way for new use cases
that depend on having two TTBRs available at EL2.
* Generalized framework for configurable ID registers from userspace.
KVM/arm64 currently prevents arbitrary CPU feature set configuration
from userspace, but the intent is to relax this limitation and allow
userspace to select a feature set consistent with the CPU.
* Enable the use of Branch Target Identification (FEAT_BTI) in the
hypervisor.
* Use a separate set of pointer authentication keys for the hypervisor
when running in protected mode, as the host is untrusted at runtime.
* Ensure timer IRQs are consistently released in the init failure
paths.
* Avoid trapping CTR_EL0 on systems with Enhanced Virtualization Traps
(FEAT_EVT), as it is a register commonly read from userspace.
* Erratum workaround for the upcoming AmpereOne part, which has broken
hardware A/D state management.
RISC-V:
* Redirect AMO load/store misaligned traps to KVM guest
* Trap-n-emulate AIA in-kernel irqchip for KVM guest
* Svnapot support for KVM Guest
s390:
* New uvdevice secret API
* CMM selftest and fixes
* fix racy access to target CPU for diag 9c
x86:
* Fix missing/incorrect #GP checks on ENCLS
* Use standard mmu_notifier hooks for handling APIC access page
* Drop now unnecessary TR/TSS load after VM-Exit on AMD
* Print more descriptive information about the status of SEV and SEV-ES during
module load
* Add a test for splitting and reconstituting hugepages during and after
dirty logging
* Add support for CPU pinning in demand paging test
* Add support for AMD PerfMonV2, with a variety of cleanups and minor fixes
included along the way
* Add a "nx_huge_pages=never" option to effectively avoid creating NX hugepage
recovery threads (because nx_huge_pages=off can be toggled at runtime)
* Move handling of PAT out of MTRR code and dedup SVM+VMX code
* Fix output of PIC poll command emulation when there's an interrupt
* Add a maintainer's handbook to document KVM x86 processes, preferred coding
style, testing expectations, etc.
* Misc cleanups, fixes and comments
Generic:
* Miscellaneous bugfixes and cleanups
Selftests:
* Generate dependency files so that partial rebuilds work as expected
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM64:
- Eager page splitting optimization for dirty logging, optionally
allowing for a VM to avoid the cost of hugepage splitting in the
stage-2 fault path.
- Arm FF-A proxy for pKVM, allowing a pKVM host to safely interact
with services that live in the Secure world. pKVM intervenes on
FF-A calls to guarantee the host doesn't misuse memory donated to
the hyp or a pKVM guest.
- Support for running the split hypervisor with VHE enabled, known as
'hVHE' mode. This is extremely useful for testing the split
hypervisor on VHE-only systems, and paves the way for new use cases
that depend on having two TTBRs available at EL2.
- Generalized framework for configurable ID registers from userspace.
KVM/arm64 currently prevents arbitrary CPU feature set
configuration from userspace, but the intent is to relax this
limitation and allow userspace to select a feature set consistent
with the CPU.
- Enable the use of Branch Target Identification (FEAT_BTI) in the
hypervisor.
- Use a separate set of pointer authentication keys for the
hypervisor when running in protected mode, as the host is untrusted
at runtime.
- Ensure timer IRQs are consistently released in the init failure
paths.
- Avoid trapping CTR_EL0 on systems with Enhanced Virtualization
Traps (FEAT_EVT), as it is a register commonly read from userspace.
- Erratum workaround for the upcoming AmpereOne part, which has
broken hardware A/D state management.
RISC-V:
- Redirect AMO load/store misaligned traps to KVM guest
- Trap-n-emulate AIA in-kernel irqchip for KVM guest
- Svnapot support for KVM Guest
s390:
- New uvdevice secret API
- CMM selftest and fixes
- fix racy access to target CPU for diag 9c
x86:
- Fix missing/incorrect #GP checks on ENCLS
- Use standard mmu_notifier hooks for handling APIC access page
- Drop now unnecessary TR/TSS load after VM-Exit on AMD
- Print more descriptive information about the status of SEV and
SEV-ES during module load
- Add a test for splitting and reconstituting hugepages during and
after dirty logging
- Add support for CPU pinning in demand paging test
- Add support for AMD PerfMonV2, with a variety of cleanups and minor
fixes included along the way
- Add a "nx_huge_pages=never" option to effectively avoid creating NX
hugepage recovery threads (because nx_huge_pages=off can be toggled
at runtime)
- Move handling of PAT out of MTRR code and dedup SVM+VMX code
- Fix output of PIC poll command emulation when there's an interrupt
- Add a maintainer's handbook to document KVM x86 processes,
preferred coding style, testing expectations, etc.
- Misc cleanups, fixes and comments
Generic:
- Miscellaneous bugfixes and cleanups
Selftests:
- Generate dependency files so that partial rebuilds work as
expected"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (153 commits)
Documentation/process: Add a maintainer handbook for KVM x86
Documentation/process: Add a label for the tip tree handbook's coding style
KVM: arm64: Fix misuse of KVM_ARM_VCPU_POWER_OFF bit index
RISC-V: KVM: Remove unneeded semicolon
RISC-V: KVM: Allow Svnapot extension for Guest/VM
riscv: kvm: define vcpu_sbi_ext_pmu in header
RISC-V: KVM: Expose IMSIC registers as attributes of AIA irqchip
RISC-V: KVM: Add in-kernel virtualization of AIA IMSIC
RISC-V: KVM: Expose APLIC registers as attributes of AIA irqchip
RISC-V: KVM: Add in-kernel emulation of AIA APLIC
RISC-V: KVM: Implement device interface for AIA irqchip
RISC-V: KVM: Skeletal in-kernel AIA irqchip support
RISC-V: KVM: Set kvm_riscv_aia_nr_hgei to zero
RISC-V: KVM: Add APLIC related defines
RISC-V: KVM: Add IMSIC related defines
RISC-V: KVM: Implement guest external interrupt line management
KVM: x86: Remove PRIx* definitions as they are solely for user space
s390/uv: Update query for secret-UVCs
s390/uv: replace scnprintf with sysfs_emit
s390/uvdevice: Add 'Lock Secret Store' UVC
...
|
||
Paolo Bonzini
|
255006adb3 |
KVM VMX changes for 6.5:
- Fix missing/incorrect #GP checks on ENCLS - Use standard mmu_notifier hooks for handling APIC access page - Misc cleanups -----BEGIN PGP SIGNATURE----- iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmSaLDYSHHNlYW5qY0Bn b29nbGUuY29tAAoJEGCRIgFNDBL5ovYP/ib86UG9QXwoEKx0mIyLQ5q1jD+StvxH 18SIH62+MXAtmz2E+EmXIySW76diOKCngApJ11WTERPwpZYEpcITh2D2Jp/vwgk5 xUPK+WKYQs1SGpJu3wXhLE1u6mB7X9p7EaXRSKG67P7YK09gTaOik1/3h6oNrGO+ KI06reCQN1PstKTfrZXxYpRlfDc761YaAmSZ79Bg+bK9PisFqme7TJ2mAqNZPFPd E7ho/UOEyWRSyd5VMsuOUB760pMQ9edKrs+38xNDp5N+0Fh0ItTjuAcd2KVWMZyW Fk+CJq4kCqTlEik5OwcEHsTGJGBFscGPSO+T0YtVfSZDdtN/rHN7l8RGquOebVTG Ldm5bg4agu4lXsqqzMxn8J9SkbNg3xno79mMSc2185jS2HLt5Hu6PzQnQ2tEtHJQ IuovmssHOVKDoYODOg0tq8UMydgT3hAvC7YJCouubCjxUUw+22nhN3EDuAhbJhtT DgQNGT7GmsrKIWLEjbm6EpLLOdJdB7/U1MrEshLS015a/DUz4b3ZGYApneifJL8h nGE2Wu+36xGUVNLgDMdvd+R17WdyQa+f+9KjUGy71KelFV4vI4A3JwvH0aIsTyHZ LGlQBZqelc66GYwMiqVC0GYGRtrdgygQopfstvZJ3rYiHZV/mdhB5A0T4J2Xvh2Q bnDNzsSFdsH5 =PjYj -----END PGP SIGNATURE----- Merge tag 'kvm-x86-vmx-6.5' of https://github.com/kvm-x86/linux into HEAD KVM VMX changes for 6.5: - Fix missing/incorrect #GP checks on ENCLS - Use standard mmu_notifier hooks for handling APIC access page - Misc cleanups |
||
|
Paolo Bonzini
|
d74669ebae |
Common KVM changes for 6.5:
- Fix unprotected vcpu->pid dereference via debugfs - Fix KVM_BUG() and KVM_BUG_ON() macros with 64-bit conditionals - Refactor failure path in kvm_io_bus_unregister_dev() to simplify the code - Misc cleanups -----BEGIN PGP SIGNATURE----- iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmSaFkUSHHNlYW5qY0Bn b29nbGUuY29tAAoJEGCRIgFNDBL5BYQP/j3BOjShMl1q7jOf+eaE6ro48ffHmPxk ujMLS1bMXY1PT937gG1uHokNp4GaotKJXILVwSFUYcrkR8LKtfou31/X9OPhUIMT nf0BBRS2KpvZSHfeqrYc0eUMgZKSkAjmtwU5Hob+EdisUZ0yT9kO3Sr4fvSqDd65 2fvcCcOdKccKfmuUQQ6a3zJBV7FDJeGAZ3GSF7eb6MzpPyRMbMu+w4K0i6AKc4uA F2U3a4DB8uH++JVwZVfBla0Rz8wvarGiIE5FRonistDTJYLzhY+VypiBHFc+mcyp KqX3TxXClndlZolqOyvFFkiIcNBFOfPJ0O5gk4whFRR3dS70Y9Ji1/Gzm9S8w52h 3Q16wLbUzyFONxznB2THTU6W+9ZKKRAPVP5R6/xkqZgnr+qWxfMQD7cNGgHuK3Nv QyNF2K1/FUrxdIkPzKa/UWDRX8rwjTDdASxLA9Zl8uP7qmfJGSWIRfjljgJYuAkr D37lDNzeoxkmuMeAQ2Rcpn1ghYOG6tm5OdZdkzjQdBjlugOTQOsZ05c/Ab2mSThy h7K6okw5a4gjsfuxCepnbmbUJ3IDedbRYzKtzwhoYuLZ/qf2F5NqbXMXpiyvHYTJ fAZpkKkF5adgagz2kU57nqzb1W0uWZdASQCXXIdEN8QdyQe/FGqgxMWKEOaywB32 C/fdKRFQoCyL =EGXd -----END PGP SIGNATURE----- Merge tag 'kvm-x86-generic-6.5' of https://github.com/kvm-x86/linux into HEAD Common KVM changes for 6.5: - Fix unprotected vcpu->pid dereference via debugfs - Fix KVM_BUG() and KVM_BUG_ON() macros with 64-bit conditionals - Refactor failure path in kvm_io_bus_unregister_dev() to simplify the code - Misc cleanups |
||
|
Paolo Bonzini
|
cc744042d9 |
KVM/arm64 updates for 6.5
- Eager page splitting optimization for dirty logging, optionally
allowing for a VM to avoid the cost of block splitting in the stage-2
fault path.
- Arm FF-A proxy for pKVM, allowing a pKVM host to safely interact with
services that live in the Secure world. pKVM intervenes on FF-A calls
to guarantee the host doesn't misuse memory donated to the hyp or a
pKVM guest.
- Support for running the split hypervisor with VHE enabled, known as
'hVHE' mode. This is extremely useful for testing the split
hypervisor on VHE-only systems, and paves the way for new use cases
that depend on having two TTBRs available at EL2.
- Generalized framework for configurable ID registers from userspace.
KVM/arm64 currently prevents arbitrary CPU feature set configuration
from userspace, but the intent is to relax this limitation and allow
userspace to select a feature set consistent with the CPU.
- Enable the use of Branch Target Identification (FEAT_BTI) in the
hypervisor.
- Use a separate set of pointer authentication keys for the hypervisor
when running in protected mode, as the host is untrusted at runtime.
- Ensure timer IRQs are consistently released in the init failure
paths.
- Avoid trapping CTR_EL0 on systems with Enhanced Virtualization Traps
(FEAT_EVT), as it is a register commonly read from userspace.
- Erratum workaround for the upcoming AmpereOne part, which has broken
hardware A/D state management.
As a consequence of the hVHE series reworking the arm64 software
features framework, the for-next/module-alloc branch from the arm64 tree
comes along for the ride.
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Merge tag 'kvmarm-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for 6.5
- Eager page splitting optimization for dirty logging, optionally
allowing for a VM to avoid the cost of block splitting in the stage-2
fault path.
- Arm FF-A proxy for pKVM, allowing a pKVM host to safely interact with
services that live in the Secure world. pKVM intervenes on FF-A calls
to guarantee the host doesn't misuse memory donated to the hyp or a
pKVM guest.
- Support for running the split hypervisor with VHE enabled, known as
'hVHE' mode. This is extremely useful for testing the split
hypervisor on VHE-only systems, and paves the way for new use cases
that depend on having two TTBRs available at EL2.
- Generalized framework for configurable ID registers from userspace.
KVM/arm64 currently prevents arbitrary CPU feature set configuration
from userspace, but the intent is to relax this limitation and allow
userspace to select a feature set consistent with the CPU.
- Enable the use of Branch Target Identification (FEAT_BTI) in the
hypervisor.
- Use a separate set of pointer authentication keys for the hypervisor
when running in protected mode, as the host is untrusted at runtime.
- Ensure timer IRQs are consistently released in the init failure
paths.
- Avoid trapping CTR_EL0 on systems with Enhanced Virtualization Traps
(FEAT_EVT), as it is a register commonly read from userspace.
- Erratum workaround for the upcoming AmpereOne part, which has broken
hardware A/D state management.
As a consequence of the hVHE series reworking the arm64 software
features framework, the for-next/module-alloc branch from the arm64 tree
comes along for the ride.
|
||
|
Linus Torvalds
|
6e17c6de3d |
- Yosry Ahmed brought back some cgroup v1 stats in OOM logs.
- Yosry has also eliminated cgroup's atomic rstat flushing. - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability. - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning. - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface. - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree. - Johannes Weiner has done some cleanup work on the compaction code. - David Hildenbrand has contributed additional selftests for get_user_pages(). - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code. - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code. - Huang Ying has done some maintenance on the swap code's usage of device refcounting. - Christoph Hellwig has some cleanups for the filemap/directio code. - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses. - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings. - John Hubbard has a series of fixes to the MM selftesting code. - ZhangPeng continues the folio conversion campaign. - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock. - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8. - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management. - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code. - Vishal Moola also has done some folio conversion work. - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZJejewAKCRDdBJ7gKXxA joggAPwKMfT9lvDBEUnJagY7dbDPky1cSYZdJKxxM2cApGa42gEA6Cl8HRAWqSOh J0qXCzqaaN8+BuEyLGDVPaXur9KirwY= =B7yQ -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull mm updates from Andrew Morton: - Yosry Ahmed brought back some cgroup v1 stats in OOM logs - Yosry has also eliminated cgroup's atomic rstat flushing - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree - Johannes Weiner has done some cleanup work on the compaction code - David Hildenbrand has contributed additional selftests for get_user_pages() - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code - Huang Ying has done some maintenance on the swap code's usage of device refcounting - Christoph Hellwig has some cleanups for the filemap/directio code - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings - John Hubbard has a series of fixes to the MM selftesting code - ZhangPeng continues the folio conversion campaign - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8 - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code - Vishal Moola also has done some folio conversion work - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch * tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits) mm/hugetlb: remove hugetlb_set_page_subpool() mm: nommu: correct the range of mmap_sem_read_lock in task_mem() hugetlb: revert use of page_cache_next_miss() Revert "page cache: fix page_cache_next/prev_miss off by one" mm/vmscan: fix root proactive reclaim unthrottling unbalanced node mm: memcg: rename and document global_reclaim() mm: kill [add|del]_page_to_lru_list() mm: compaction: convert to use a folio in isolate_migratepages_block() mm: zswap: fix double invalidate with exclusive loads mm: remove unnecessary pagevec includes mm: remove references to pagevec mm: rename invalidate_mapping_pagevec to mapping_try_invalidate mm: remove struct pagevec net: convert sunrpc from pagevec to folio_batch i915: convert i915_gpu_error to use a folio_batch pagevec: rename fbatch_count() mm: remove check_move_unevictable_pages() drm: convert drm_gem_put_pages() to use a folio_batch i915: convert shmem_sg_free_table() to use a folio_batch scatterlist: add sg_set_folio() ... |
||
Gavin Shan
|
2230f9e117 |
KVM: Avoid illegal stage2 mapping on invalid memory slot
We run into guest hang in edk2 firmware when KSM is kept as running on
the host. The edk2 firmware is waiting for status 0x80 from QEMU's pflash
device (TYPE_PFLASH_CFI01) during the operation of sector erasing or
buffered write. The status is returned by reading the memory region of
the pflash device and the read request should have been forwarded to QEMU
and emulated by it. Unfortunately, the read request is covered by an
illegal stage2 mapping when the guest hang issue occurs. The read request
is completed with QEMU bypassed and wrong status is fetched. The edk2
firmware runs into an infinite loop with the wrong status.
The illegal stage2 mapping is populated due to same page sharing by KSM
at (C) even the associated memory slot has been marked as invalid at (B)
when the memory slot is requested to be deleted. It's notable that the
active and inactive memory slots can't be swapped when we're in the middle
of kvm_mmu_notifier_change_pte() because kvm->mn_active_invalidate_count
is elevated, and kvm_swap_active_memslots() will busy loop until it reaches
to zero again. Besides, the swapping from the active to the inactive memory
slots is also avoided by holding &kvm->srcu in __kvm_handle_hva_range(),
corresponding to synchronize_srcu_expedited() in kvm_swap_active_memslots().
CPU-A CPU-B
----- -----
ioctl(kvm_fd, KVM_SET_USER_MEMORY_REGION)
kvm_vm_ioctl_set_memory_region
kvm_set_memory_region
__kvm_set_memory_region
kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE)
kvm_invalidate_memslot
kvm_copy_memslot
kvm_replace_memslot
kvm_swap_active_memslots (A)
kvm_arch_flush_shadow_memslot (B)
same page sharing by KSM
kvm_mmu_notifier_invalidate_range_start
:
kvm_mmu_notifier_change_pte
kvm_handle_hva_range
__kvm_handle_hva_range
kvm_set_spte_gfn (C)
:
kvm_mmu_notifier_invalidate_range_end
Fix the issue by skipping the invalid memory slot at (C) to avoid the
illegal stage2 mapping so that the read request for the pflash's status
is forwarded to QEMU and emulated by it. In this way, the correct pflash's
status can be returned from QEMU to break the infinite loop in the edk2
firmware.
We tried a git-bisect and the first problematic commit is
|
||
Ryan Roberts
|
c33c794828 |
mm: ptep_get() conversion
Convert all instances of direct pte_t* dereferencing to instead use ptep_get() helper. This means that by default, the accesses change from a C dereference to a READ_ONCE(). This is technically the correct thing to do since where pgtables are modified by HW (for access/dirty) they are volatile and therefore we should always ensure READ_ONCE() semantics. But more importantly, by always using the helper, it can be overridden by the architecture to fully encapsulate the contents of the pte. Arch code is deliberately not converted, as the arch code knows best. It is intended that arch code (arm64) will override the default with its own implementation that can (e.g.) hide certain bits from the core code, or determine young/dirty status by mixing in state from another source. Conversion was done using Coccinelle: ---- // $ make coccicheck \ // COCCI=ptepget.cocci \ // SPFLAGS="--include-headers" \ // MODE=patch virtual patch @ depends on patch @ pte_t *v; @@ - *v + ptep_get(v) ---- Then reviewed and hand-edited to avoid multiple unnecessary calls to ptep_get(), instead opting to store the result of a single call in a variable, where it is correct to do so. This aims to negate any cost of READ_ONCE() and will benefit arch-overrides that may be more complex. Included is a fix for an issue in an earlier version of this patch that was pointed out by kernel test robot. The issue arose because config MMU=n elides definition of the ptep helper functions, including ptep_get(). HUGETLB_PAGE=n configs still define a simple huge_ptep_clear_flush() for linking purposes, which dereferences the ptep. So when both configs are disabled, this caused a build error because ptep_get() is not defined. Fix by continuing to do a direct dereference when MMU=n. This is safe because for this config the arch code cannot be trying to virtualize the ptes because none of the ptep helpers are defined. Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/ Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Oliver Upton
|
83510396c0 |
Merge branch kvm-arm64/eager-page-splitting into kvmarm/next
* kvm-arm64/eager-page-splitting: : Eager Page Splitting, courtesy of Ricardo Koller. : : Dirty logging performance is dominated by the cost of splitting : hugepages to PTE granularity. On systems that mere mortals can get their : hands on, each fault incurs the cost of a full break-before-make : pattern, wherein the broadcast invalidation and ensuing serialization : significantly increases fault latency. : : The goal of eager page splitting is to move the cost of hugepage : splitting out of the stage-2 fault path and instead into the ioctls : responsible for managing the dirty log: : : - If manual protection is enabled for the VM, hugepage splitting : happens in the KVM_CLEAR_DIRTY_LOG ioctl. This is desirable as it : provides userspace granular control over hugepage splitting. : : - Otherwise, if userspace relies on the legacy dirty log behavior : (clear on collection), hugepage splitting is done at the moment dirty : logging is enabled for a particular memslot. : : Support for eager page splitting requires explicit opt-in from : userspace, which is realized through the : KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE capability. arm64: kvm: avoid overflow in integer division KVM: arm64: Use local TLBI on permission relaxation KVM: arm64: Split huge pages during KVM_CLEAR_DIRTY_LOG KVM: arm64: Open-code kvm_mmu_write_protect_pt_masked() KVM: arm64: Split huge pages when dirty logging is enabled KVM: arm64: Add kvm_uninit_stage2_mmu() KVM: arm64: Refactor kvm_arch_commit_memory_region() KVM: arm64: Add kvm_pgtable_stage2_split() KVM: arm64: Add KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE KVM: arm64: Export kvm_are_all_memslots_empty() KVM: arm64: Add helper for creating unlinked stage2 subtrees KVM: arm64: Add KVM_PGTABLE_WALK flags for skipping CMOs and BBM TLBIs KVM: arm64: Rename free_removed to free_unlinked Signed-off-by: Oliver Upton <oliver.upton@linux.dev> |
||
Wei Wang
|
cc77b95acf |
kvm/eventfd: use list_for_each_entry when deassign ioeventfd
Simpify kvm_deassign_ioeventfd_idx to use list_for_each_entry as the loop just ends at the entry that's found and deleted. Note, coalesced_mmio_ops and ioeventfd_ops are the only instances of kvm_io_device_ops that implement a destructor, all other callers of kvm_io_bus_unregister_dev() are unaffected by this change. Suggested-by: Michal Luczaj <mhal@rbox.co> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20230207123713.3905-3-wei.w.wang@intel.com [sean: call out that only select users implement a destructor] Signed-off-by: Sean Christopherson <seanjc@google.com> |
||
|
Wei Wang
|
5ea5ca3c2b |
KVM: destruct kvm_io_device while unregistering it from kvm_io_bus
Current usage of kvm_io_device requires users to destruct it with an extra call of kvm_iodevice_destructor after the device gets unregistered from kvm_io_bus. This is not necessary and can cause errors if a user forgot to make the extra call. Simplify the usage by combining kvm_iodevice_destructor into kvm_io_bus_unregister_dev. This reduces LOCs a bit for users and can avoid the leakage of destructing the device explicitly. Signed-off-by: Wei Wang <wei.w.wang@intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20230207123713.3905-2-wei.w.wang@intel.com Signed-off-by: Sean Christopherson <seanjc@google.com> |
||
Lorenzo Stoakes
|
ca5e863233 |
mm/gup: remove vmas parameter from get_user_pages_remote()
The only instances of get_user_pages_remote() invocations which used the vmas parameter were for a single page which can instead simply look up the VMA directly. In particular:- - __update_ref_ctr() looked up the VMA but did nothing with it so we simply remove it. - __access_remote_vm() was already using vma_lookup() when the original lookup failed so by doing the lookup directly this also de-duplicates the code. We are able to perform these VMA operations as we already hold the mmap_lock in order to be able to call get_user_pages_remote(). As part of this work we add get_user_page_vma_remote() which abstracts the VMA lookup, error handling and decrementing the page reference count should the VMA lookup fail. This forms part of a broader set of patches intended to eliminate the vmas parameter altogether. [akpm@linux-foundation.org: avoid passing NULL to PTR_ERR] Link: https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64) Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390) Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
54d020692b |
mm/gup: remove unused vmas parameter from get_user_pages()
Patch series "remove the vmas parameter from GUP APIs", v6. (pin_/get)_user_pages[_remote]() each provide an optional output parameter for an array of VMA objects associated with each page in the input range. These provide the means for VMAs to be returned, as long as mm->mmap_lock is never released during the GUP operation (i.e. the internal flag FOLL_UNLOCKABLE is not specified). In addition, these VMAs can only be accessed with the mmap_lock held and become invalidated the moment it is released. The vast majority of invocations do not use this functionality and of those that do, all but one case retrieve a single VMA to perform checks upon. It is not egregious in the single VMA cases to simply replace the operation with a vma_lookup(). In these cases we duplicate the (fast) lookup on a slow path already under the mmap_lock, abstracted to a new get_user_page_vma_remote() inline helper function which also performs error checking and reference count maintenance. The special case is io_uring, where io_pin_pages() specifically needs to assert that the VMAs underlying the range do not result in broken long-term GUP file-backed mappings. As GUP now internally asserts that FOLL_LONGTERM mappings are not file-backed in a broken fashion (i.e. requiring dirty tracking) - as implemented in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast writing to file-backed mappings" - this logic is no longer required and so we can simply remove it altogether from io_uring. Eliminating the vmas parameter eliminates an entire class of danging pointer errors that might have occured should the lock have been incorrectly released. In addition, the API is simplified and now clearly expresses what it is intended for - applying the specified GUP flags and (if pinning) returning pinned pages. This change additionally opens the door to further potential improvements in GUP and the possible marrying of disparate code paths. I have run this series against gup_test with no issues. Thanks to Matthew Wilcox for suggesting this refactoring! This patch (of 6): No invocation of get_user_pages() use the vmas parameter, so remove it. The GUP API is confusing and caveated. Recent changes have done much to improve that, however there is more we can do. Exporting vmas is a prime target as the caller has to be extremely careful to preclude their use after the mmap_lock has expired or otherwise be left with dangling pointers. Removing the vmas parameter focuses the GUP functions upon their primary purpose - pinning (and outputting) pages as well as performing the actions implied by the input flags. This is part of a patch series aiming to remove the vmas parameter altogether. Link: https://lkml.kernel.org/r/cover.1684350871.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/589e0c64794668ffc799651e8d85e703262b1e9d.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Christian König <christian.koenig@amd.com> (for radeon parts) Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Sean Christopherson <seanjc@google.com> (KVM) Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Michal Luczaj
|
5f643e460a |
KVM: Clean up kvm_vm_ioctl_create_vcpu()
Since
|
||
Sean Christopherson
|
0a8a5f2c8c |
KVM: x86: Use standard mmu_notifier invalidate hooks for APIC access page
Now that KVM honors past and in-progress mmu_notifier invalidations when reloading the APIC-access page, use KVM's "standard" invalidation hooks to trigger a reload and delete the one-off usage of invalidate_range(). Aside from eliminating one-off code in KVM, dropping KVM's use of invalidate_range() will allow common mmu_notifier to redefine the API to be more strictly focused on invalidating secondary TLBs that share the primary MMU's page tables. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lore.kernel.org/r/20230602011518.787006-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com> |
||
|
Michal Luczaj
|
70b0bc4c0a |
KVM: Don't kfree(NULL) on kzalloc() failure in kvm_assign_ioeventfd_idx()
On kzalloc() failure, taking the `goto fail` path leads to kfree(NULL). Such no-op has no use. Move it out. Signed-off-by: Michal Luczaj <mhal@rbox.co> Reviewed-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Link: https://lore.kernel.org/r/20230327175457.735903-1-mhal@rbox.co Signed-off-by: Sean Christopherson <seanjc@google.com> |
||
|
Sean Christopherson
|
76021e96d7 |
KVM: Protect vcpu->pid dereference via debugfs with RCU
Wrap the vcpu->pid dereference in the debugfs hook vcpu_get_pid() with
proper RCU read (un)lock. Unlike the code in kvm_vcpu_ioctl(),
vcpu_get_pid() is not a simple access; the pid pointer is passed to
pid_nr() and fully dereferenced if the pointer is non-NULL.
Failure to acquire RCU could result in use-after-free of the old pid if
a different task invokes KVM_RUN and puts the last reference to the old
vcpu->pid between vcpu_get_pid() reading the pointer and dereferencing it
in pid_nr().
Fixes:
|
||
|
Michal Luczaj
|
afb2acb2e3 |
KVM: Fix vcpu_array[0] races
In kvm_vm_ioctl_create_vcpu(), add vcpu to vcpu_array iff it's safe to
access vcpu via kvm_get_vcpu() and kvm_for_each_vcpu(), i.e. when there's
no failure path requiring vcpu removal and destruction. Such order is
important because vcpu_array accessors may end up referencing vcpu at
vcpu_array[0] even before online_vcpus is set to 1.
When online_vcpus=0, any call to kvm_get_vcpu() goes through
array_index_nospec() and ends with an attempt to xa_load(vcpu_array, 0):
int num_vcpus = atomic_read(&kvm->online_vcpus);
i = array_index_nospec(i, num_vcpus);
return xa_load(&kvm->vcpu_array, i);
Similarly, when online_vcpus=0, a kvm_for_each_vcpu() does not iterate over
an "empty" range, but actually [0, ULONG_MAX]:
xa_for_each_range(&kvm->vcpu_array, idx, vcpup, 0, \
(atomic_read(&kvm->online_vcpus) - 1))
In both cases, such online_vcpus=0 edge case, even if leading to
unnecessary calls to XArray API, should not be an issue; requesting
unpopulated indexes/ranges is handled by xa_load() and xa_for_each_range().
However, this means that when the first vCPU is created and inserted in
vcpu_array *and* before online_vcpus is incremented, code calling
kvm_get_vcpu()/kvm_for_each_vcpu() already has access to that first vCPU.
This should not pose a problem assuming that once a vcpu is stored in
vcpu_array, it will remain there, but that's not the case:
kvm_vm_ioctl_create_vcpu() first inserts to vcpu_array, then requests a
file descriptor. If create_vcpu_fd() fails, newly inserted vcpu is removed
from the vcpu_array, then destroyed:
vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
r = xa_insert(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, GFP_KERNEL_ACCOUNT);
kvm_get_kvm(kvm);
r = create_vcpu_fd(vcpu);
if (r < 0) {
xa_erase(&kvm->vcpu_array, vcpu->vcpu_idx);
kvm_put_kvm_no_destroy(kvm);
goto unlock_vcpu_destroy;
}
atomic_inc(&kvm->online_vcpus);
This results in a possible race condition when a reference to a vcpu is
acquired (via kvm_get_vcpu() or kvm_for_each_vcpu()) moments before said
vcpu is destroyed.
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Message-Id: <20230510140410.1093987-2-mhal@rbox.co>
Cc: stable@vger.kernel.org
Fixes:
|
||
|
Sean Christopherson
|
e0ceec221f |
KVM: Don't enable hardware after a restart/shutdown is initiated
Reject hardware enabling, i.e. VM creation, if a restart/shutdown has
been initiated to avoid re-enabling hardware between kvm_reboot() and
machine_{halt,power_off,restart}(). The restart case is especially
problematic (for x86) as enabling VMX (or clearing GIF in KVM_RUN on
SVM) blocks INIT, which results in the restart/reboot hanging as BIOS
is unable to wake and rendezvous with APs.
Note, this bug, and the original issue that motivated the addition of
kvm_reboot(), is effectively limited to a forced reboot, e.g. `reboot -f`.
In a "normal" reboot, userspace will gracefully teardown userspace before
triggering the kernel reboot (modulo bugs, errors, etc), i.e. any process
that might do ioctl(KVM_CREATE_VM) is long gone.
Fixes:
|
||
|
Sean Christopherson
|
6735150b69 |
KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown
Use syscore_ops.shutdown to disable hardware virtualization during a reboot instead of using the dedicated reboot_notifier so that KVM disables virtualization _after_ system_state has been updated. This will allow fixing a race in KVM's handling of a forced reboot where KVM can end up enabling hardware virtualization between kernel_restart_prepare() and machine_restart(). Rename KVM's hook to match the syscore op to avoid any possible confusion from wiring up a "reboot" helper to a "shutdown" hook (neither "shutdown nor "reboot" is completely accurate as the hook handles both). Opportunistically rewrite kvm_shutdown()'s comment to make it less VMX specific, and to explain why kvm_rebooting exists. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Zenghui Yu <yuzenghui@huawei.com> Cc: kvmarm@lists.linux.dev Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com> Cc: Anup Patel <anup@brainfault.org> Cc: Atish Patra <atishp@atishpatra.org> Cc: kvm-riscv@lists.infradead.org Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Message-Id: <20230512233127.804012-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
Ricardo Koller
|
26f457142d |
KVM: arm64: Export kvm_are_all_memslots_empty()
Export kvm_are_all_memslots_empty(). This will be used by a future commit when checking before setting a capability. Signed-off-by: Ricardo Koller <ricarkol@google.com> Reviewed-by: Shaoqin Huang <shahuang@redhat.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Link: https://lore.kernel.org/r/20230426172330.1439644-5-ricarkol@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev> |
||
|
Linus Torvalds
|
c8c655c34e |
s390:
* More phys_to_virt conversions
* Improvement of AP management for VSIE (nested virtualization)
ARM64:
* Numerous fixes for the pathological lock inversion issue that
plagued KVM/arm64 since... forever.
* New framework allowing SMCCC-compliant hypercalls to be forwarded
to userspace, hopefully paving the way for some more features
being moved to VMMs rather than be implemented in the kernel.
* Large rework of the timer code to allow a VM-wide offset to be
applied to both virtual and physical counters as well as a
per-timer, per-vcpu offset that complements the global one.
This last part allows the NV timer code to be implemented on
top.
* A small set of fixes to make sure that we don't change anything
affecting the EL1&0 translation regime just after having having
taken an exception to EL2 until we have executed a DSB. This
ensures that speculative walks started in EL1&0 have completed.
* The usual selftest fixes and improvements.
KVM x86 changes for 6.4:
* Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled,
and by giving the guest control of CR0.WP when EPT is enabled on VMX
(VMX-only because SVM doesn't support per-bit controls)
* Add CR0/CR4 helpers to query single bits, and clean up related code
where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return
as a bool
* Move AMD_PSFD to cpufeatures.h and purge KVM's definition
* Avoid unnecessary writes+flushes when the guest is only adding new PTEs
* Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s optimizations
when emulating invalidations
* Clean up the range-based flushing APIs
* Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a single
A/D bit using a LOCK AND instead of XCHG, and skip all of the "handle
changed SPTE" overhead associated with writing the entire entry
* Track the number of "tail" entries in a pte_list_desc to avoid having
to walk (potentially) all descriptors during insertion and deletion,
which gets quite expensive if the guest is spamming fork()
* Disallow virtualizing legacy LBRs if architectural LBRs are available,
the two are mutually exclusive in hardware
* Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES)
after KVM_RUN, similar to CPUID features
* Overhaul the vmx_pmu_caps selftest to better validate PERF_CAPABILITIES
* Apply PMU filters to emulated events and add test coverage to the
pmu_event_filter selftest
x86 AMD:
* Add support for virtual NMIs
* Fixes for edge cases related to virtual interrupts
x86 Intel:
* Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if XTILE_DATA is
not being reported due to userspace not opting in via prctl()
* Fix a bug in emulation of ENCLS in compatibility mode
* Allow emulation of NOP and PAUSE for L2
* AMX selftests improvements
* Misc cleanups
MIPS:
* Constify MIPS's internal callbacks (a leftover from the hardware enabling
rework that landed in 6.3)
Generic:
* Drop unnecessary casts from "void *" throughout kvm_main.c
* Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the struct
size by 8 bytes on 64-bit kernels by utilizing a padding hole
Documentation:
* Fix goof introduced by the conversion to rST
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"s390:
- More phys_to_virt conversions
- Improvement of AP management for VSIE (nested virtualization)
ARM64:
- Numerous fixes for the pathological lock inversion issue that
plagued KVM/arm64 since... forever.
- New framework allowing SMCCC-compliant hypercalls to be forwarded
to userspace, hopefully paving the way for some more features being
moved to VMMs rather than be implemented in the kernel.
- Large rework of the timer code to allow a VM-wide offset to be
applied to both virtual and physical counters as well as a
per-timer, per-vcpu offset that complements the global one. This
last part allows the NV timer code to be implemented on top.
- A small set of fixes to make sure that we don't change anything
affecting the EL1&0 translation regime just after having having
taken an exception to EL2 until we have executed a DSB. This
ensures that speculative walks started in EL1&0 have completed.
- The usual selftest fixes and improvements.
x86:
- Optimize CR0.WP toggling by avoiding an MMU reload when TDP is
enabled, and by giving the guest control of CR0.WP when EPT is
enabled on VMX (VMX-only because SVM doesn't support per-bit
controls)
- Add CR0/CR4 helpers to query single bits, and clean up related code
where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long"
return as a bool
- Move AMD_PSFD to cpufeatures.h and purge KVM's definition
- Avoid unnecessary writes+flushes when the guest is only adding new
PTEs
- Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s
optimizations when emulating invalidations
- Clean up the range-based flushing APIs
- Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a
single A/D bit using a LOCK AND instead of XCHG, and skip all of
the "handle changed SPTE" overhead associated with writing the
entire entry
- Track the number of "tail" entries in a pte_list_desc to avoid
having to walk (potentially) all descriptors during insertion and
deletion, which gets quite expensive if the guest is spamming
fork()
- Disallow virtualizing legacy LBRs if architectural LBRs are
available, the two are mutually exclusive in hardware
- Disallow writes to immutable feature MSRs (notably
PERF_CAPABILITIES) after KVM_RUN, similar to CPUID features
- Overhaul the vmx_pmu_caps selftest to better validate
PERF_CAPABILITIES
- Apply PMU filters to emulated events and add test coverage to the
pmu_event_filter selftest
- AMD SVM:
- Add support for virtual NMIs
- Fixes for edge cases related to virtual interrupts
- Intel AMX:
- Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if
XTILE_DATA is not being reported due to userspace not opting in
via prctl()
- Fix a bug in emulation of ENCLS in compatibility mode
- Allow emulation of NOP and PAUSE for L2
- AMX selftests improvements
- Misc cleanups
MIPS:
- Constify MIPS's internal callbacks (a leftover from the hardware
enabling rework that landed in 6.3)
Generic:
- Drop unnecessary casts from "void *" throughout kvm_main.c
- Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the
struct size by 8 bytes on 64-bit kernels by utilizing a padding
hole
Documentation:
- Fix goof introduced by the conversion to rST"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (211 commits)
KVM: s390: pci: fix virtual-physical confusion on module unload/load
KVM: s390: vsie: clarifications on setting the APCB
KVM: s390: interrupt: fix virtual-physical confusion for next alert GISA
KVM: arm64: Have kvm_psci_vcpu_on() use WRITE_ONCE() to update mp_state
KVM: arm64: Acquire mp_state_lock in kvm_arch_vcpu_ioctl_vcpu_init()
KVM: selftests: Test the PMU event "Instructions retired"
KVM: selftests: Copy full counter values from guest in PMU event filter test
KVM: selftests: Use error codes to signal errors in PMU event filter test
KVM: selftests: Print detailed info in PMU event filter asserts
KVM: selftests: Add helpers for PMC asserts in PMU event filter test
KVM: selftests: Add a common helper for the PMU event filter guest code
KVM: selftests: Fix spelling mistake "perrmited" -> "permitted"
KVM: arm64: vhe: Drop extra isb() on guest exit
KVM: arm64: vhe: Synchronise with page table walker on MMU update
KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc()
KVM: arm64: nvhe: Synchronise with page table walker on TLBI
KVM: arm64: Handle 32bit CNTPCTSS traps
KVM: arm64: nvhe: Synchronise with page table walker on vcpu run
KVM: arm64: vgic: Don't acquire its_lock before config_lock
KVM: selftests: Add test to verify KVM's supported XCR0
...
|
||
|
Linus Torvalds
|
f20730efbd |
SMP cross-CPU function-call updates for v6.4:
- Remove diagnostics and adjust config for CSD lock diagnostics
- Add a generic IPI-sending tracepoint, as currently there's no easy
way to instrument IPI origins: it's arch dependent and for some
major architectures it's not even consistently available.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'smp-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP cross-CPU function-call updates from Ingo Molnar:
- Remove diagnostics and adjust config for CSD lock diagnostics
- Add a generic IPI-sending tracepoint, as currently there's no easy
way to instrument IPI origins: it's arch dependent and for some major
architectures it's not even consistently available.
* tag 'smp-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
trace,smp: Trace all smp_function_call*() invocations
trace: Add trace_ipi_send_cpu()
sched, smp: Trace smp callback causing an IPI
smp: reword smp call IPI comment
treewide: Trace IPIs sent via smp_send_reschedule()
irq_work: Trace self-IPIs sent via arch_irq_work_raise()
smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
sched, smp: Trace IPIs sent via send_call_function_single_ipi()
trace: Add trace_ipi_send_cpumask()
kernel/smp: Make csdlock_debug= resettable
locking/csd_lock: Remove per-CPU data indirection from CSD lock debugging
locking/csd_lock: Remove added data from CSD lock debugging
locking/csd_lock: Add Kconfig option for csd_debug default
|
||
Alexey Kardashevskiy
|
52882b9c7a |
KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE platform dependent
When introduced, IRQFD resampling worked on POWER8 with XICS. However
KVM on POWER9 has never implemented it - the compatibility mode code
("XICS-on-XIVE") misses the kvm_notify_acked_irq() call and the native
XIVE mode does not handle INTx in KVM at all.
This moved the capability support advertising to platforms and stops
advertising it on XIVE, i.e. POWER9 and later.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Anup Patel <anup@brainfault.org>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20220504074807.3616813-1-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
||
Dmytro Maluka
|
fef8f2b90e |
KVM: x86/ioapic: Resample the pending state of an IRQ when unmasking
KVM irqfd based emulation of level-triggered interrupts doesn't work
quite correctly in some cases, particularly in the case of interrupts
that are handled in a Linux guest as oneshot interrupts (IRQF_ONESHOT).
Such an interrupt is acked to the device in its threaded irq handler,
i.e. later than it is acked to the interrupt controller (EOI at the end
of hardirq), not earlier.
Linux keeps such interrupt masked until its threaded handler finishes,
to prevent the EOI from re-asserting an unacknowledged interrupt.
However, with KVM + vfio (or whatever is listening on the resamplefd)
we always notify resamplefd at the EOI, so vfio prematurely unmasks the
host physical IRQ, thus a new physical interrupt is fired in the host.
This extra interrupt in the host is not a problem per se. The problem is
that it is unconditionally queued for injection into the guest, so the
guest sees an extra bogus interrupt. [*]
There are observed at least 2 user-visible issues caused by those
extra erroneous interrupts for a oneshot irq in the guest:
1. System suspend aborted due to a pending wakeup interrupt from
ChromeOS EC (drivers/platform/chrome/cros_ec.c).
2. Annoying "invalid report id data" errors from ELAN0000 touchpad
(drivers/input/mouse/elan_i2c_core.c), flooding the guest dmesg
every time the touchpad is touched.
The core issue here is that by the time when the guest unmasks the IRQ,
the physical IRQ line is no longer asserted (since the guest has
acked the interrupt to the device in the meantime), yet we
unconditionally inject the interrupt queued into the guest by the
previous resampling. So to fix the issue, we need a way to detect that
the IRQ is no longer pending, and cancel the queued interrupt in this
case.
With IOAPIC we are not able to probe the physical IRQ line state
directly (at least not if the underlying physical interrupt controller
is an IOAPIC too), so in this patch we use irqfd resampler for that.
Namely, instead of injecting the queued interrupt, we just notify the
resampler that this interrupt is done. If the IRQ line is actually
already deasserted, we are done. If it is still asserted, a new
interrupt will be shortly triggered through irqfd and injected into the
guest.
In the case if there is no irqfd resampler registered for this IRQ, we
cannot fix the issue, so we keep the existing behavior: immediately
unconditionally inject the queued interrupt.
This patch fixes the issue for x86 IOAPIC only. In the long run, we can
fix it for other irqchips and other architectures too, possibly taking
advantage of reading the physical state of the IRQ line, which is
possible with some other irqchips (e.g. with arm64 GIC, maybe even with
the legacy x86 PIC).
[*] In this description we assume that the interrupt is a physical host
interrupt forwarded to the guest e.g. by vfio. Potentially the same
issue may occur also with a purely virtual interrupt from an
emulated device, e.g. if the guest handles this interrupt, again, as
a oneshot interrupt.
Signed-off-by: Dmytro Maluka <dmy@semihalf.com>
Link: https://lore.kernel.org/kvm/31420943-8c5f-125c-a5ee-d2fde2700083@semihalf.com/
Link: https://lore.kernel.org/lkml/87o7wrug0w.wl-maz@kernel.org/
Message-Id: <20230322204344.50138-3-dmy@semihalf.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
||
|
Dmytro Maluka
|
d583fbd706 |
KVM: irqfd: Make resampler_list an RCU list
It is useful to be able to do read-only traversal of the list of all the registered irqfd resamplers without locking the resampler_lock mutex. In particular, we are going to traverse it to search for a resampler registered for the given irq of an irqchip, and that will be done with an irqchip spinlock (ioapic->lock) held, so it is undesirable to lock a mutex in this context. So turn this list into an RCU list. For protecting the read side, reuse kvm->irq_srcu which is already used for protecting a number of irq related things (kvm->irq_routing, irqfd->resampler->list, kvm->irq_ack_notifier_list, kvm->arch.mask_notifier_list). Signed-off-by: Dmytro Maluka <dmy@semihalf.com> Message-Id: <20230322204344.50138-2-dmy@semihalf.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
Jun Miao
|
b0d237087c |
KVM: Fix comments that refer to the non-existent install_new_memslots()
Fix stale comments that were left behind when install_new_memslots() was
replaced by kvm_swap_active_memslots() as part of the scalable memslots
rework.
Fixes:
|
||
Valentin Schneider
|
4c8c3c7f70 |
treewide: Trace IPIs sent via smp_send_reschedule()
To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.
Changes to include the declaration of the tracepoint were driven by the
following coccinelle script:
@func_use@
@@
smp_send_reschedule(...);
@include@
@@
#include <trace/events/ipi.h>
@no_include depends on func_use && !include@
@@
#include <...>
+
+ #include <trace/events/ipi.h>
[csky bits]
[riscv bits]
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230307143558.294354-6-vschneid@redhat.com
|
||
Li kunyu
|
14aa40a1d0 |
kvm: kvm_main: Remove unnecessary (void*) conversions
void * pointer assignment does not require a forced replacement. Signed-off-by: Li kunyu <kunyu@nfschina.com> Link: https://lore.kernel.org/r/20221213080236.3969-1-kunyu@nfschina.com Signed-off-by: Sean Christopherson <seanjc@google.com> |
||
Thomas Huth
|
f15ba52bfa |
KVM: Standardize on "int" return types instead of "long" in kvm_main.c
KVM functions use "long" return values for functions that are wired up to "struct file_operations", but otherwise use "int" return values for functions that can return 0/-errno in order to avoid unintentional divergences between 32-bit and 64-bit kernels. Some code still uses "long" in unnecessary spots, though, which can cause a little bit of confusion and unnecessary size casts. Let's change these spots to use "int" types, too. Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <20230208140105.655814-6-thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
|
Paolo Bonzini
|
33436335e9 |
KVM/riscv changes for 6.3
- Fix wrong usage of PGDIR_SIZE to check page sizes - Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() - Redirect illegal instruction traps to guest - SBI PMU support for guest -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEZdn75s5e6LHDQ+f/rUjsVaLHLAcFAmPifFIACgkQrUjsVaLH LAcEyxAAinMBaBhiPmwWZQvcCzh/UFmJo8BQCwAPuwoc/a4ZGAR7ylzd0oJilP8M wSgX6Ad8XF+CEW2VpxW9nwyi41N25ep1Lrf8vOaWy9L9QNUo0t15WrCIbXT2p399 HrK9fz7HHKKIMsJy+rYb9EepdmMf55xtr1Y/EjyvhoDQbrEMlKsAODYz/SUoriQG Tn3cCYBzLdvzDzu0xXM9v+nsetWXdajK/v4je+mE3NQceXhePAO4oVWP4IpnoROd ZQm3evvVdf0WtKG9curxwMB7jjBqDBFrcLYl0qHGa7pi2o5PzVM7esgaV47KwetH IgA/Mrf1IfzpgM7VYDDax5wUHlKj63KisqU0J8rU3PUloQXaWqv7+ho51t9GzZ/i 9x4uyO/evVntgyTw6HCbqmQJDgEtJiG1ydrR/ydBMYHLnh7LPY2UpKgcqmirtbkK 1/DYDp84vikQ5VW1hc8IACdoBShh9Moh4xsEStzkTrIeHcZCjtORXUh8UIPZ0Mu2 7Mnkktu9I55SLwA3rwH/EYT1ISrOV1G+q3wfqgeLpn8YUWwCIiqWQ5Ur0/WSMJse uJ3HedZDzj9T4n4khX+mKEYh6joAafQZag+4TID2lRSwd0S/mpeC22hYrViMdDmq yhE+JNin/sz4AVaHNzGwfqk2NC2RFl9aRn2X0xTwyBubif9pKMQ= =spUL -----END PGP SIGNATURE----- Merge tag 'kvm-riscv-6.3-1' of https://github.com/kvm-riscv/linux into HEAD KVM/riscv changes for 6.3 - Fix wrong usage of PGDIR_SIZE to check page sizes - Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() - Redirect illegal instruction traps to guest - SBI PMU support for guest |
||
|
Sean Christopherson
|
b1cb1fac22 |
KVM: Destroy target device if coalesced MMIO unregistration fails
Destroy and free the target coalesced MMIO device if unregistering said
device fails. As clearly noted in the code, kvm_io_bus_unregister_dev()
does not destroy the target device.
BUG: memory leak
unreferenced object 0xffff888112a54880 (size 64):
comm "syz-executor.2", pid 5258, jiffies 4297861402 (age 14.129s)
hex dump (first 32 bytes):
38 c7 67 15 00 c9 ff ff 38 c7 67 15 00 c9 ff ff 8.g.....8.g.....
e0 c7 e1 83 ff ff ff ff 00 30 67 15 00 c9 ff ff .........0g.....
backtrace:
[<0000000006995a8a>] kmalloc include/linux/slab.h:556 [inline]
[<0000000006995a8a>] kzalloc include/linux/slab.h:690 [inline]
[<0000000006995a8a>] kvm_vm_ioctl_register_coalesced_mmio+0x8e/0x3d0 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:150
[<00000000022550c2>] kvm_vm_ioctl+0x47d/0x1600 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3323
[<000000008a75102f>] vfs_ioctl fs/ioctl.c:46 [inline]
[<000000008a75102f>] file_ioctl fs/ioctl.c:509 [inline]
[<000000008a75102f>] do_vfs_ioctl+0xbab/0x1160 fs/ioctl.c:696
[<0000000080e3f669>] ksys_ioctl+0x76/0xa0 fs/ioctl.c:713
[<0000000059ef4888>] __do_sys_ioctl fs/ioctl.c:720 [inline]
[<0000000059ef4888>] __se_sys_ioctl fs/ioctl.c:718 [inline]
[<0000000059ef4888>] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
[<000000006444fa05>] do_syscall_64+0x9f/0x4e0 arch/x86/entry/common.c:290
[<000000009a4ed50b>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
BUG: leak checking failed
Fixes:
|
||
|
Paolo Bonzini
|
dc7c31e922 |
Merge branch 'kvm-v6.2-rc4-fixes' into HEAD
ARM: * Fix the PMCR_EL0 reset value after the PMU rework * Correctly handle S2 fault triggered by a S1 page table walk by not always classifying it as a write, as this breaks on R/O memslots * Document why we cannot exit with KVM_EXIT_MMIO when taking a write fault from a S1 PTW on a R/O memslot * Put the Apple M2 on the naughty list for not being able to correctly implement the vgic SEIS feature, just like the M1 before it * Reviewer updates: Alex is stepping down, replaced by Zenghui x86: * Fix various rare locking issues in Xen emulation and teach lockdep to detect them * Documentation improvements * Do not return host topology information from KVM_GET_SUPPORTED_CPUID |
||
|
Linus Torvalds
|
7bf70dbb18 |
VFIO fixes for v6.2-rc6
- Honor reserved regions when testing for IOMMU find grained super
page support, avoiding a regression on s390 for a firmware device
where the existence of the mapping, even if unused can trigger
an error state. (Niklas Schnelle)
- Fix a deadlock in releasing KVM references by using the alternate
.release() rather than .destroy() callback for the kvm-vfio device.
(Yi Liu)
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Merge tag 'vfio-v6.2-rc6' of https://github.com/awilliam/linux-vfio
Pull VFIO fixes from Alex Williamson:
- Honor reserved regions when testing for IOMMU find grained super page
support, avoiding a regression on s390 for a firmware device where
the existence of the mapping, even if unused can trigger an error
state. (Niklas Schnelle)
- Fix a deadlock in releasing KVM references by using the alternate
.release() rather than .destroy() callback for the kvm-vfio device.
(Yi Liu)
* tag 'vfio-v6.2-rc6' of https://github.com/awilliam/linux-vfio:
kvm/vfio: Fix potential deadlock on vfio group_lock
vfio/type1: Respect IOMMU reserved regions in vfio_test_domain_fgsp()
|
||
Yi Liu
|
51cdc8bc12 |
kvm/vfio: Fix potential deadlock on vfio group_lock
Currently it is possible that the final put of a KVM reference comes from
vfio during its device close operation. This occurs while the vfio group
lock is held; however, if the vfio device is still in the kvm device list,
then the following call chain could result in a deadlock:
VFIO holds group->group_lock/group_rwsem
-> kvm_put_kvm
-> kvm_destroy_vm
-> kvm_destroy_devices
-> kvm_vfio_destroy
-> kvm_vfio_file_set_kvm
-> vfio_file_set_kvm
-> try to hold group->group_lock/group_rwsem
The key function is the kvm_destroy_devices() which triggers destroy cb
of kvm_device_ops. It calls back to vfio and try to hold group_lock. So
if this path doesn't call back to vfio, this dead lock would be fixed.
Actually, there is a way for it. KVM provides another point to free the
kvm-vfio device which is the point when the device file descriptor is
closed. This can be achieved by providing the release cb instead of the
destroy cb. Also rename kvm_vfio_destroy() to be kvm_vfio_release().
/*
* Destroy is responsible for freeing dev.
*
* Destroy may be called before or after destructors are called
* on emulated I/O regions, depending on whether a reference is
* held by a vcpu or other kvm component that gets destroyed
* after the emulated I/O.
*/
void (*destroy)(struct kvm_device *dev);
/*
* Release is an alternative method to free the device. It is
* called when the device file descriptor is closed. Once
* release is called, the destroy method will not be called
* anymore as the device is removed from the device list of
* the VM. kvm->lock is held.
*/
void (*release)(struct kvm_device *dev);
Fixes:
|
||
David Woodhouse
|
42a90008f8 |
KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering rule
Documentation/virt/kvm/locking.rst tells us that kvm->lock is taken outside vcpu->mutex. But that doesn't actually happen very often; it's only in some esoteric cases like migration with AMD SEV. This means that lockdep usually doesn't notice, and doesn't do its job of keeping us honest. Ensure that lockdep *always* knows about the ordering of these two locks, by briefly taking vcpu->mutex in kvm_vm_ioctl_create_vcpu() while kvm->lock is held. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20230111180651.14394-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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9f1a4c0048 |
KVM: Clean up error labels in kvm_init()
Convert the last two "out" lables to "err" labels now that the dust has settled, i.e. now that there are no more planned changes to the order of things in kvm_init(). Use "err" instead of "out" as it's easier to describe what failed than it is to describe what needs to be unwound, e.g. if allocating a per-CPU kick mask fails, KVM needs to free any masks that were allocated, and of course needs to unwind previous operations. Reported-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-51-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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441f7bfa99 |
KVM: Opt out of generic hardware enabling on s390 and PPC
Allow architectures to opt out of the generic hardware enabling logic, and opt out on both s390 and PPC, which don't need to manually enable virtualization as it's always on (when available). In addition to letting s390 and PPC drop a bit of dead code, this will hopefully also allow ARM to clean up its related code, e.g. ARM has its own per-CPU flag to track which CPUs have enable hardware due to the need to keep hardware enabled indefinitely when pKVM is enabled. Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-50-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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35774a9f94 |
KVM: Register syscore (suspend/resume) ops early in kvm_init()
Register the suspend/resume notifier hooks at the same time KVM registers its reboot notifier so that all the code in kvm_init() that deals with enabling/disabling hardware is bundled together. Opportunstically move KVM's implementations to reside near the reboot notifier code for the same reason. Bunching the code together will allow architectures to opt out of KVM's generic hardware enable/disable logic with minimal #ifdeffery. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-49-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Isaku Yamahata
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e6fb7d6eb4 |
KVM: Make hardware_enable_failed a local variable in the "enable all" path
Rework detecting hardware enabling errors to use a local variable in the "enable all" path to track whether or not enabling was successful across all CPUs. Using a global variable complicates paths that enable hardware only on the current CPU, e.g. kvm_resume() and kvm_online_cpu(). Opportunistically add a WARN if hardware enabling fails during kvm_resume(), KVM is all kinds of hosed if CPU0 fails to enable hardware. The WARN is largely futile in the current code, as KVM BUG()s on spurious faults on VMX instructions, e.g. attempting to run a vCPU on CPU if hardware enabling fails will explode. ------------[ cut here ]------------ kernel BUG at arch/x86/kvm/x86.c:508! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 1009 Comm: CPU 4/KVM Not tainted 6.1.0-rc1+ #11 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kvm_spurious_fault+0xa/0x10 Call Trace: vmx_vcpu_load_vmcs+0x192/0x230 [kvm_intel] vmx_vcpu_load+0x16/0x60 [kvm_intel] kvm_arch_vcpu_load+0x32/0x1f0 vcpu_load+0x2f/0x40 kvm_arch_vcpu_ioctl_run+0x19/0x9d0 kvm_vcpu_ioctl+0x271/0x660 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x2b/0x50 entry_SYSCALL_64_after_hwframe+0x46/0xb0 But, the WARN may provide a breadcrumb to understand what went awry, and someday KVM may fix one or both of those bugs, e.g. by finding a way to eat spurious faults no matter the context (easier said than done due to side effects of certain operations, e.g. Intel's VMCLEAR). Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> [sean: rebase, WARN on failure in kvm_resume()] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-48-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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37d2588185 |
KVM: Use a per-CPU variable to track which CPUs have enabled virtualization
Use a per-CPU variable instead of a shared bitmap to track which CPUs
have successfully enabled virtualization hardware. Using a per-CPU bool
avoids the need for an additional allocation, and arguably yields easier
to read code. Using a bitmap would be advantageous if KVM used it to
avoid generating IPIs to CPUs that failed to enable hardware, but that's
an extreme edge case and not worth optimizing, and the low level helpers
would still want to keep their individual checks as attempting to enable
virtualization hardware when it's already enabled can be problematic,
e.g. Intel's VMXON will fault.
Opportunistically change the order in hardware_enable_nolock() to set
the flag if and only if hardware enabling is successful, instead of
speculatively setting the flag and then clearing it on failure.
Add a comment explaining that the check in hardware_disable_nolock()
isn't simply paranoia. Waaay back when, commit
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Isaku Yamahata
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667a83bf6a |
KVM: Remove on_each_cpu(hardware_disable_nolock) in kvm_exit()
Drop the superfluous invocation of hardware_disable_nolock() during kvm_exit(), as it's nothing more than a glorified nop. KVM automatically disables hardware on all CPUs when the last VM is destroyed, and kvm_exit() cannot be called until the last VM goes away as the calling module is pinned by an elevated refcount of the fops associated with /dev/kvm. This holds true even on x86, where the caller of kvm_exit() is not kvm.ko, but is instead a dependent module, kvm_amd.ko or kvm_intel.ko, as kvm_chardev_ops.owner is set to the module that calls kvm_init(), not hardcoded to the base kvm.ko module. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> [sean: rework changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-46-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Isaku Yamahata
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0bf50497f0 |
KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock
Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock now that KVM hooks CPU hotplug during the ONLINE phase, which can sleep. Previously, KVM hooked the STARTING phase, which is not allowed to sleep and thus could not take kvm_lock (a mutex). This effectively allows the task that's initiating hardware enabling/disabling to preempted and/or migrated. Note, the Documentation/virt/kvm/locking.rst statement that kvm_count_lock is "raw" because hardware enabling/disabling needs to be atomic with respect to migration is wrong on multiple fronts. First, while regular spinlocks can be preempted, the task holding the lock cannot be migrated. Second, preventing migration is not required. on_each_cpu() disables preemption, which ensures that cpus_hardware_enabled correctly reflects hardware state. The task may be preempted/migrated between bumping kvm_usage_count and invoking on_each_cpu(), but that's perfectly ok as kvm_usage_count is still protected, e.g. other tasks that call hardware_enable_all() will be blocked until the preempted/migrated owner exits its critical section. KVM does have lockless accesses to kvm_usage_count in the suspend/resume flows, but those are safe because all tasks must be frozen prior to suspending CPUs, and a task cannot be frozen while it holds one or more locks (userspace tasks are frozen via a fake signal). Preemption doesn't need to be explicitly disabled in the hotplug path. The hotplug thread is pinned to the CPU that's being hotplugged, and KVM only cares about having a stable CPU, i.e. to ensure hardware is enabled on the correct CPU. Lockep, i.e. check_preemption_disabled(), plays nice with this state too, as is_percpu_thread() is true for the hotplug thread. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-45-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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2c106f2900 |
KVM: Ensure CPU is stable during low level hardware enable/disable
Use the non-raw smp_processor_id() in the low hardware enable/disable helpers as KVM absolutely relies on the CPU being stable, e.g. KVM would end up with incorrect state if the task were migrated between accessing cpus_hardware_enabled and actually enabling/disabling hardware. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-44-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Chao Gao
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e4aa7f88af |
KVM: Disable CPU hotplug during hardware enabling/disabling
Disable CPU hotplug when enabling/disabling hardware to prevent the
corner case where if the following sequence occurs:
1. A hotplugged CPU marks itself online in cpu_online_mask
2. The hotplugged CPU enables interrupt before invoking KVM's ONLINE
callback
3 hardware_{en,dis}able_all() is invoked on another CPU
the hotplugged CPU will be included in on_each_cpu() and thus get sent
through hardware_{en,dis}able_nolock() before kvm_online_cpu() is called.
start_secondary { ...
set_cpu_online(smp_processor_id(), true); <- 1
...
local_irq_enable(); <- 2
...
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); <- 3
}
KVM currently fudges around this race by keeping track of which CPUs have
done hardware enabling (see commit
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Chao Gao
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aaf12a7b43 |
KVM: Rename and move CPUHP_AP_KVM_STARTING to ONLINE section
The CPU STARTING section doesn't allow callbacks to fail. Move KVM's hotplug callback to ONLINE section so that it can abort onlining a CPU in certain cases to avoid potentially breaking VMs running on existing CPUs. For example, when KVM fails to enable hardware virtualization on the hotplugged CPU. Place KVM's hotplug state before CPUHP_AP_SCHED_WAIT_EMPTY as it ensures when offlining a CPU, all user tasks and non-pinned kernel tasks have left the CPU, i.e. there cannot be a vCPU task around. So, it is safe for KVM's CPU offline callback to disable hardware virtualization at that point. Likewise, KVM's online callback can enable hardware virtualization before any vCPU task gets a chance to run on hotplugged CPUs. Drop kvm_x86_check_processor_compatibility()'s WARN that IRQs are disabled, as the ONLINE section runs with IRQs disabled. The WARN wasn't intended to be a requirement, e.g. disabling preemption is sufficient, the IRQ thing was purely an aggressive sanity check since the helper was only ever invoked via SMP function call. Rename KVM's CPU hotplug callbacks accordingly. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Reviewed-by: Yuan Yao <yuan.yao@intel.com> [sean: drop WARN that IRQs are disabled] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-42-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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81a1cf9f89 |
KVM: Drop kvm_arch_check_processor_compat() hook
Drop kvm_arch_check_processor_compat() and its support code now that all architecture implementations are nops. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Acked-by: Anup Patel <anup@brainfault.org> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20221130230934.1014142-33-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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a578a0a9e3 |
KVM: Drop kvm_arch_{init,exit}() hooks
Drop kvm_arch_init() and kvm_arch_exit() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-30-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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63a1bd8ad1 |
KVM: Drop arch hardware (un)setup hooks
Drop kvm_arch_hardware_setup() and kvm_arch_hardware_unsetup() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Sean Christopherson
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73b8dc0413 |
KVM: Teardown VFIO ops earlier in kvm_exit()
Move the call to kvm_vfio_ops_exit() further up kvm_exit() to try and
bring some amount of symmetry to the setup order in kvm_init(), and more
importantly so that the arch hooks are invoked dead last by kvm_exit().
This will allow arch code to move away from the arch hooks without any
change in ordering between arch code and common code in kvm_exit().
That kvm_vfio_ops_exit() is called last appears to be 100% arbitrary. It
was bolted on after the fact by commit
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Sean Christopherson
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c9650228ef |
KVM: Allocate cpus_hardware_enabled after arch hardware setup
Allocate cpus_hardware_enabled after arch hardware setup so that arch "init" and "hardware setup" are called back-to-back and thus can be combined in a future patch. cpus_hardware_enabled is never used before kvm_create_vm(), i.e. doesn't have a dependency with hardware setup and only needs to be allocated before /dev/kvm is exposed to userspace. Free the object before the arch hooks are invoked to maintain symmetry, and so that arch code can move away from the hooks without having to worry about ordering changes. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Yuan Yao <yuan.yao@intel.com> Message-Id: <20221130230934.1014142-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |