111 Commits

Author SHA1 Message Date
Wei Wang
e2e83a73d7 docs: kvm: fix WARNINGs from api.rst
Use the api number 134 for KVM_GET_XSAVE2, instead of 42, which has been
used by KVM_GET_XSAVE.
Also, fix the WARNINGs of the underlines being too short.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Message-Id: <20220120045003.315177-1-wei.w.wang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-20 12:13:35 -05:00
Guang Zeng
be50b2065d kvm: x86: Add support for getting/setting expanded xstate buffer
With KVM_CAP_XSAVE, userspace uses a hardcoded 4KB buffer to get/set
xstate data from/to KVM. This doesn't work when dynamic xfeatures
(e.g. AMX) are exposed to the guest as they require a larger buffer
size.

Introduce a new capability (KVM_CAP_XSAVE2). Userspace VMM gets the
required xstate buffer size via KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2).
KVM_SET_XSAVE is extended to work with both legacy and new capabilities
by doing properly-sized memdup_user() based on the guest fpu container.
KVM_GET_XSAVE is kept for backward-compatible reason. Instead,
KVM_GET_XSAVE2 is introduced under KVM_CAP_XSAVE2 as the preferred
interface for getting xstate buffer (4KB or larger size) from KVM
(Link: https://lkml.org/lkml/2021/12/15/510)

Also, update the api doc with the new KVM_GET_XSAVE2 ioctl.

Signed-off-by: Guang Zeng <guang.zeng@intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-19-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-14 13:44:41 -05:00
Jing Liu
445ecdf79b kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID
KVM_GET_SUPPORTED_CPUID should not include any dynamic xstates in
CPUID[0xD] if they have not been requested with prctl. Otherwise
a process which directly passes KVM_GET_SUPPORTED_CPUID to
KVM_SET_CPUID2 would now fail even if it doesn't intend to use a
dynamically enabled feature. Userspace must know that prctl is
required and allocate >4K xstate buffer before setting any dynamic
bit.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-5-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07 13:33:04 -05:00
David Woodhouse
14243b3871 KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery
This adds basic support for delivering 2 level event channels to a guest.

Initially, it only supports delivery via the IRQ routing table, triggered
by an eventfd. In order to do so, it has a kvm_xen_set_evtchn_fast()
function which will use the pre-mapped shared_info page if it already
exists and is still valid, while the slow path through the irqfd_inject
workqueue will remap the shared_info page if necessary.

It sets the bits in the shared_info page but not the vcpu_info; that is
deferred to __kvm_xen_has_interrupt() which raises the vector to the
appropriate vCPU.

Add a 'verbose' mode to xen_shinfo_test while adding test cases for this.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211210163625.2886-5-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07 10:44:45 -05:00
David Woodhouse
1cfc9c4b9d KVM: x86/xen: Maintain valid mapping of Xen shared_info page
Use the newly reinstated gfn_to_pfn_cache to maintain a kernel mapping
of the Xen shared_info page so that it can be accessed in atomic context.

Note that we do not participate in dirty tracking for the shared info
page and we do not explicitly mark it dirty every single tim we deliver
an event channel interrupts. We wouldn't want to do that even if we *did*
have a valid vCPU context with which to do so.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211210163625.2886-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-07 10:44:45 -05:00
Janis Schoetterl-Glausch
49ae248b61 KVM: s390: Fix names of skey constants in api documentation
They are defined in include/uapi/linux/kvm.h as
KVM_S390_GET_SKEYS_NONE and KVM_S390_SKEYS_MAX, but the
api documetation talks of KVM_S390_GET_KEYS_NONE and
KVM_S390_SKEYS_ALLOC_MAX respectively.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20211118102522.569660-1-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2021-12-07 09:35:32 +00:00
Peter Gonda
b56639318b KVM: SEV: Add support for SEV intra host migration
For SEV to work with intra host migration, contents of the SEV info struct
such as the ASID (used to index the encryption key in the AMD SP) and
the list of memory regions need to be transferred to the target VM.
This change adds a commands for a target VMM to get a source SEV VM's sev
info.

Signed-off-by: Peter Gonda <pgonda@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Message-Id: <20211021174303.385706-3-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-11 10:35:27 -05:00
Oliver Upton
c68dc1b577 KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK
Handling the migration of TSCs correctly is difficult, in part because
Linux does not provide userspace with the ability to retrieve a (TSC,
realtime) clock pair for a single instant in time. In lieu of a more
convenient facility, KVM can report similar information in the kvm_clock
structure.

Provide userspace with a host TSC & realtime pair iff the realtime clock
is based on the TSC. If userspace provides KVM_SET_CLOCK with a valid
realtime value, advance the KVM clock by the amount of elapsed time. Do
not step the KVM clock backwards, though, as it is a monotonic
oscillator.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210916181538.968978-5-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-18 14:43:44 -04:00
Anup Patel
da40d85805 RISC-V: KVM: Document RISC-V specific parts of KVM API
Document RISC-V specific parts of the KVM API, such as:
 - The interrupt numbers passed to the KVM_INTERRUPT ioctl.
 - The states supported by the KVM_{GET,SET}_MP_STATE ioctls.
 - The registers supported by the KVM_{GET,SET}_ONE_REG interface
   and the encoding of those register ids.
 - The exit reason KVM_EXIT_RISCV_SBI for SBI calls forwarded to
   userspace tool.

CC: Jonathan Corbet <corbet@lwn.net>
CC: linux-doc@vger.kernel.org
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-10-04 16:12:34 +05:30
Linus Torvalds
192ad3c27a ARM:
- Page ownership tracking between host EL1 and EL2
 
 - Rely on userspace page tables to create large stage-2 mappings
 
 - Fix incompatibility between pKVM and kmemleak
 
 - Fix the PMU reset state, and improve the performance of the virtual PMU
 
 - Move over to the generic KVM entry code
 
 - Address PSCI reset issues w.r.t. save/restore
 
 - Preliminary rework for the upcoming pKVM fixed feature
 
 - A bunch of MM cleanups
 
 - a vGIC fix for timer spurious interrupts
 
 - Various cleanups
 
 s390:
 
 - enable interpretation of specification exceptions
 
 - fix a vcpu_idx vs vcpu_id mixup
 
 x86:
 
 - fast (lockless) page fault support for the new MMU
 
 - new MMU now the default
 
 - increased maximum allowed VCPU count
 
 - allow inhibit IRQs on KVM_RUN while debugging guests
 
 - let Hyper-V-enabled guests run with virtualized LAPIC as long as they
   do not enable the Hyper-V "AutoEOI" feature
 
 - fixes and optimizations for the toggling of AMD AVIC (virtualized LAPIC)
 
 - tuning for the case when two-dimensional paging (EPT/NPT) is disabled
 
 - bugfixes and cleanups, especially with respect to 1) vCPU reset and
   2) choosing a paging mode based on CR0/CR4/EFER
 
 - support for 5-level page table on AMD processors
 
 Generic:
 
 - MMU notifier invalidation callbacks do not take mmu_lock unless necessary
 
 - improved caching of LRU kvm_memory_slot
 
 - support for histogram statistics
 
 - add statistics for halt polling and remote TLB flush requests
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "ARM:
   - Page ownership tracking between host EL1 and EL2
   - Rely on userspace page tables to create large stage-2 mappings
   - Fix incompatibility between pKVM and kmemleak
   - Fix the PMU reset state, and improve the performance of the virtual
     PMU
   - Move over to the generic KVM entry code
   - Address PSCI reset issues w.r.t. save/restore
   - Preliminary rework for the upcoming pKVM fixed feature
   - A bunch of MM cleanups
   - a vGIC fix for timer spurious interrupts
   - Various cleanups

  s390:
   - enable interpretation of specification exceptions
   - fix a vcpu_idx vs vcpu_id mixup

  x86:
   - fast (lockless) page fault support for the new MMU
   - new MMU now the default
   - increased maximum allowed VCPU count
   - allow inhibit IRQs on KVM_RUN while debugging guests
   - let Hyper-V-enabled guests run with virtualized LAPIC as long as
     they do not enable the Hyper-V "AutoEOI" feature
   - fixes and optimizations for the toggling of AMD AVIC (virtualized
     LAPIC)
   - tuning for the case when two-dimensional paging (EPT/NPT) is
     disabled
   - bugfixes and cleanups, especially with respect to vCPU reset and
     choosing a paging mode based on CR0/CR4/EFER
   - support for 5-level page table on AMD processors

  Generic:
   - MMU notifier invalidation callbacks do not take mmu_lock unless
     necessary
   - improved caching of LRU kvm_memory_slot
   - support for histogram statistics
   - add statistics for halt polling and remote TLB flush requests"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (210 commits)
  KVM: Drop unused kvm_dirty_gfn_invalid()
  KVM: x86: Update vCPU's hv_clock before back to guest when tsc_offset is adjusted
  KVM: MMU: mark role_regs and role accessors as maybe unused
  KVM: MIPS: Remove a "set but not used" variable
  x86/kvm: Don't enable IRQ when IRQ enabled in kvm_wait
  KVM: stats: Add VM stat for remote tlb flush requests
  KVM: Remove unnecessary export of kvm_{inc,dec}_notifier_count()
  KVM: x86/mmu: Move lpage_disallowed_link further "down" in kvm_mmu_page
  KVM: x86/mmu: Relocate kvm_mmu_page.tdp_mmu_page for better cache locality
  Revert "KVM: x86: mmu: Add guest physical address check in translate_gpa()"
  KVM: x86/mmu: Remove unused field mmio_cached in struct kvm_mmu_page
  kvm: x86: Increase KVM_SOFT_MAX_VCPUS to 710
  kvm: x86: Increase MAX_VCPUS to 1024
  kvm: x86: Set KVM_MAX_VCPU_ID to 4*KVM_MAX_VCPUS
  KVM: VMX: avoid running vmx_handle_exit_irqoff in case of emulation
  KVM: x86/mmu: Don't freak out if pml5_root is NULL on 4-level host
  KVM: s390: index kvm->arch.idle_mask by vcpu_idx
  KVM: s390: Enable specification exception interpretation
  KVM: arm64: Trim guest debug exception handling
  KVM: SVM: Add 5-level page table support for SVM
  ...
2021-09-07 13:40:51 -07:00
Linus Torvalds
4ac6d90867 Yet another set of documentation changes:
- A reworking of PDF generation to yield better results for documents
    using CJK fonts in particular.
 
  - A new set of translations into traditional Chinese, a dialect for which
    I am assured there is a community of interested readers.
 
  - A lot more regular Chinese translation work as well.
 
 ...plus the usual assortment of updates, fixes, typo tweaks, etc.
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Merge tag 'docs-5.15' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "Yet another set of documentation changes:

   - A reworking of PDF generation to yield better results for documents
     using CJK fonts in particular.

   - A new set of translations into traditional Chinese, a dialect for
     which I am assured there is a community of interested readers.

   - A lot more regular Chinese translation work as well.

  ... plus the usual assortment of updates, fixes, typo tweaks, etc"

* tag 'docs-5.15' of git://git.lwn.net/linux: (55 commits)
  docs: sphinx-requirements: Move sphinx_rtd_theme to top
  docs: pdfdocs: Enable language-specific font choice of zh_TW translations
  docs: pdfdocs: Teach xeCJK about character classes of quotation marks
  docs: pdfdocs: Permit AutoFakeSlant for CJK fonts
  docs: pdfdocs: One-half spacing for CJK translations
  docs: pdfdocs: Add conf.py local to translations for ascii-art alignment
  docs: pdfdocs: Preserve inter-phrase space in Korean translations
  docs: pdfdocs: Choose Serif font as CJK mainfont if possible
  docs: pdfdocs: Add CJK-language-specific font settings
  docs: pdfdocs: Refactor config for CJK document
  scripts/kernel-doc: Override -Werror from KCFLAGS with KDOC_WERROR
  docs/zh_CN: Add zh_CN/accounting/psi.rst
  doc: align Italian translation
  Documentation/features/vm: riscv supports THP now
  docs/zh_CN: add infiniband user_verbs translation
  docs/zh_CN: add infiniband user_mad translation
  docs/zh_CN: add infiniband tag_matching translation
  docs/zh_CN: add infiniband sysfs translation
  docs/zh_CN: add infiniband opa_vnic translation
  docs/zh_CN: add infiniband ipoib translation
  ...
2021-09-01 18:49:47 -07:00
Maxim Levitsky
61e5f69ef0 KVM: x86: implement KVM_GUESTDBG_BLOCKIRQ
KVM_GUESTDBG_BLOCKIRQ will allow KVM to block all interrupts
while running.

This change is mostly intended for more robust single stepping
of the guest and it has the following benefits when enabled:

* Resuming from a breakpoint is much more reliable.
  When resuming execution from a breakpoint, with interrupts enabled,
  more often than not, KVM would inject an interrupt and make the CPU
  jump immediately to the interrupt handler and eventually return to
  the breakpoint, to trigger it again.

  From the user point of view it looks like the CPU never executed a
  single instruction and in some cases that can even prevent forward
  progress, for example, when the breakpoint is placed by an automated
  script (e.g lx-symbols), which does something in response to the
  breakpoint and then continues the guest automatically.
  If the script execution takes enough time for another interrupt to
  arrive, the guest will be stuck on the same breakpoint RIP forever.

* Normal single stepping is much more predictable, since it won't
  land the debugger into an interrupt handler.

* RFLAGS.TF has less chance to be leaked to the guest:

  We set that flag behind the guest's back to do single stepping
  but if single step lands us into an interrupt/exception handler
  it will be leaked to the guest in the form of being pushed
  to the stack.
  This doesn't completely eliminate this problem as exceptions
  can still happen, but at least this reduces the chances
  of this happening.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210811122927.900604-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-20 16:06:37 -04:00
Jing Zhang
0176ec5129 KVM: stats: Update doc for histogram statistics
Add documentations for linear and logarithmic histogram statistics.

Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210802165633.1866976-3-jingzhangos@google.com>
[Small changes to the phrasing. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-20 16:06:32 -04:00
Mauro Carvalho Chehab
3b1c8c5682 docs: virt: kvm: api.rst: replace some characters
The conversion tools used during DocBook/LaTeX/html/Markdown->ReST
conversion and some cut-and-pasted text contain some characters that
aren't easily reachable on standard keyboards and/or could cause
troubles when parsed by the documentation build system.

Replace the occurences of the following characters:

	- U+00a0 (' '): NO-BREAK SPACE
	  as it can cause lines being truncated on PDF output

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Message-Id: <ff70cb42d63f3a1da66af1b21b8d038418ed5189.1626947264.git.mchehab+huawei@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-07-26 08:26:06 -04:00
Vitaly Kuznetsov
0e691ee7b5 KVM: Documentation: Fix KVM_CAP_ENFORCE_PV_FEATURE_CPUID name
'KVM_CAP_ENFORCE_PV_CPUID' doesn't match the define in
include/uapi/linux/kvm.h.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210722092628.236474-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-07-26 08:24:30 -04:00
Mauro Carvalho Chehab
b426d9d78e docs: virt: kvm: api.rst: replace some characters
The conversion tools used during DocBook/LaTeX/html/Markdown->ReST
conversion and some cut-and-pasted text contain some characters that
aren't easily reachable on standard keyboards and/or could cause
troubles when parsed by the documentation build system.

Replace the occurences of the following characters:

	- U+00a0 (' '): NO-BREAK SPACE
	  as it can cause lines being truncated on PDF output

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/ff70cb42d63f3a1da66af1b21b8d038418ed5189.1626947264.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-07-25 14:35:46 -06:00
Ioana Ciornei
a9fd134be7 docs: kvm: properly format code blocks and lists
Add a '::' so that a code block is interpreted properly and also add a
blank line before the start of a list.

Fixes: fdc09ddd4064 ("KVM: stats: Add documentation for binary statistics interface")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20210722100356.635078-4-ciorneiioana@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-07-25 14:34:33 -06:00
Ioana Ciornei
8b9671643d docs: kvm: fix build warnings
Fix some small build warnings. The title underline was too short in some
cases and a code block was not indented.

Documentation/virt/kvm/api.rst:7216: WARNING: Title underline too short.

Fixes: 6dba94035203 ("KVM: x86: Introduce KVM_GET_SREGS2 / KVM_SET_SREGS2")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20210722100356.635078-3-ciorneiioana@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-07-25 14:34:33 -06:00
Linus Torvalds
233a806b00 This was a reasonably active cycle for documentation; this pull includes:
- Some kernel-doc cleanups.  That script is still regex onslaught from
    hell, but it has gotten a little better.
 
  - Improvements to the checkpatch docs, which are also used by the tool
    itself.
 
  - A major update to the pathname lookup documentation.
 
  - Elimination of :doc: markup, since our automarkup magic can create
    references from filenames without all the extra noise.
 
  - The flurry of Chinese translation activity continues.
 
 Plus, of course, the usual collection of updates, typo fixes, and warning
 fixes.
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Merge tag 'docs-5.14' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "This was a reasonably active cycle for documentation; this includes:

   - Some kernel-doc cleanups. That script is still regex onslaught from
     hell, but it has gotten a little better.

   - Improvements to the checkpatch docs, which are also used by the
     tool itself.

   - A major update to the pathname lookup documentation.

   - Elimination of :doc: markup, since our automarkup magic can create
     references from filenames without all the extra noise.

   - The flurry of Chinese translation activity continues.

  Plus, of course, the usual collection of updates, typo fixes, and
  warning fixes"

* tag 'docs-5.14' of git://git.lwn.net/linux: (115 commits)
  docs: path-lookup: use bare function() rather than literals
  docs: path-lookup: update symlink description
  docs: path-lookup: update get_link() ->follow_link description
  docs: path-lookup: update WALK_GET, WALK_PUT desc
  docs: path-lookup: no get_link()
  docs: path-lookup: update i_op->put_link and cookie description
  docs: path-lookup: i_op->follow_link replaced with i_op->get_link
  docs: path-lookup: Add macro name to symlink limit description
  docs: path-lookup: remove filename_mountpoint
  docs: path-lookup: update do_last() part
  docs: path-lookup: update path_mountpoint() part
  docs: path-lookup: update path_to_nameidata() part
  docs: path-lookup: update follow_managed() part
  docs: Makefile: Use CONFIG_SHELL not SHELL
  docs: Take a little noise out of the build process
  docs: x86: avoid using ReST :doc:`foo` markup
  docs: virt: kvm: s390-pv-boot.rst: avoid using ReST :doc:`foo` markup
  docs: userspace-api: landlock.rst: avoid using ReST :doc:`foo` markup
  docs: trace: ftrace.rst: avoid using ReST :doc:`foo` markup
  docs: trace: coresight: coresight.rst: avoid using ReST :doc:`foo` markup
  ...
2021-06-28 16:53:05 -07:00
Paolo Bonzini
b8917b4ae4 KVM/arm64 updates for v5.14.
- Add MTE support in guests, complete with tag save/restore interface
 - Reduce the impact of CMOs by moving them in the page-table code
 - Allow device block mappings at stage-2
 - Reduce the footprint of the vmemmap in protected mode
 - Support the vGIC on dumb systems such as the Apple M1
 - Add selftest infrastructure to support multiple configuration
   and apply that to PMU/non-PMU setups
 - Add selftests for the debug architecture
 - The usual crop of PMU fixes
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Merge tag 'kvmarm-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for v5.14.

- Add MTE support in guests, complete with tag save/restore interface
- Reduce the impact of CMOs by moving them in the page-table code
- Allow device block mappings at stage-2
- Reduce the footprint of the vmemmap in protected mode
- Support the vGIC on dumb systems such as the Apple M1
- Add selftest infrastructure to support multiple configuration
  and apply that to PMU/non-PMU setups
- Add selftests for the debug architecture
- The usual crop of PMU fixes
2021-06-25 11:24:24 -04:00
Aaron Lewis
19238e75bd kvm: x86: Allow userspace to handle emulation errors
Add a fallback mechanism to the in-kernel instruction emulator that
allows userspace the opportunity to process an instruction the emulator
was unable to.  When the in-kernel instruction emulator fails to process
an instruction it will either inject a #UD into the guest or exit to
userspace with exit reason KVM_INTERNAL_ERROR.  This is because it does
not know how to proceed in an appropriate manner.  This feature lets
userspace get involved to see if it can figure out a better path
forward.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20210510144834.658457-2-aaronlewis@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-24 18:00:48 -04:00
Sean Christopherson
63f5a1909f KVM: x86: Alert userspace that KVM_SET_CPUID{,2} after KVM_RUN is broken
Warn userspace that KVM_SET_CPUID{,2} after KVM_RUN "may" cause guest
instability.  Initialize last_vmentry_cpu to -1 and use it to detect if
the vCPU has been run at least once when its CPUID model is changed.

KVM does not correctly handle changes to paging related settings in the
guest's vCPU model after KVM_RUN, e.g. MAXPHYADDR, GBPAGES, etc...  KVM
could theoretically zap all shadow pages, but actually making that happen
is a mess due to lock inversion (vcpu->mutex is held).  And even then,
updating paging settings on the fly would only work if all vCPUs are
stopped, updated in concert with identical settings, then restarted.

To support running vCPUs with different vCPU models (that affect paging),
KVM would need to track all relevant information in kvm_mmu_page_role.
Note, that's the _page_ role, not the full mmu_role.  Updating mmu_role
isn't sufficient as a vCPU can reuse a shadow page translation that was
created by a vCPU with different settings and thus completely skip the
reserved bit checks (that are tied to CPUID).

Tracking CPUID state in kvm_mmu_page_role is _extremely_ undesirable as
it would require doubling gfn_track from a u16 to a u32, i.e. would
increase KVM's memory footprint by 2 bytes for every 4kb of guest memory.
E.g. MAXPHYADDR (6 bits), GBPAGES, AMD vs. INTEL = 1 bit, and SEV C-BIT
would all need to be tracked.

In practice, there is no remotely sane use case for changing any paging
related CPUID entries on the fly, so just sweep it under the rug (after
yelling at userspace).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-24 18:00:36 -04:00
Jing Zhang
fdc09ddd40 KVM: stats: Add documentation for binary statistics interface
This new API provides a file descriptor for every VM and VCPU to read
KVM statistics data in binary format.
It is meant to provide a lightweight, flexible, scalable and efficient
lock-free solution for user space telemetry applications to pull the
statistics data periodically for large scale systems. The pulling
frequency could be as high as a few times per second.
The statistics descriptors are defined by KVM in kernel and can be
by userspace to discover VM/VCPU statistics during the one-time setup
stage.
The statistics data itself could be read out by userspace telemetry
periodically without any extra parsing or setup effort.
There are a few existed interface protocols and definitions, but no
one can fulfil all the requirements this interface implemented as
below:
1. During high frequency periodic stats reading, there should be no
   extra efforts except the stats data read itself.
2. Support stats annotation, like type (cumulative, instantaneous,
   peak, histogram, etc) and unit (counter, time, size, cycles, etc).
3. The stats data reading should be free of lock/synchronization. We
   don't care about the consistency between all the stats data. All
   stats data can not be read out at exactly the same time. We really
   care about the change or trend of the stats data. The lock-free
   solution is not just for efficiency and scalability, also for the
   stats data accuracy and usability. For example, in the situation
   that all the stats data readings are protected by a global lock,
   if one VCPU died somehow with that lock held, then all stats data
   reading would be blocked, then we have no way from stats data that
   which VCPU has died.
4. The stats data reading workload can be handed over to other
   unprivileged process.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210618222709.1858088-6-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-24 18:00:23 -04:00
Paolo Bonzini
c3ab0e28a4 Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEAD
- Support for the H_RPT_INVALIDATE hypercall

- Conversion of Book3S entry/exit to C

- Bug fixes
2021-06-23 07:30:41 -04:00
Bharata B Rao
b87cc116c7 KVM: PPC: Book3S HV: Add KVM_CAP_PPC_RPT_INVALIDATE capability
Now that we have H_RPT_INVALIDATE fully implemented, enable
support for the same via KVM_CAP_PPC_RPT_INVALIDATE KVM capability

Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210621085003.904767-6-bharata@linux.ibm.com
2021-06-22 23:38:28 +10:00
Steven Price
04c02c201d KVM: arm64: Document MTE capability and ioctl
A new capability (KVM_CAP_ARM_MTE) identifies that the kernel supports
granting a guest access to the tags, and provides a mechanism for the
VMM to enable it.

A new ioctl (KVM_ARM_MTE_COPY_TAGS) provides a simple way for a VMM to
access the tags of a guest without having to maintain a PROT_MTE mapping
in userspace. The above capability gates access to the ioctl.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210621111716.37157-7-steven.price@arm.com
2021-06-22 14:08:07 +01:00
Ashish Kalra
0dbb112304 KVM: X86: Introduce KVM_HC_MAP_GPA_RANGE hypercall
This hypercall is used by the SEV guest to notify a change in the page
encryption status to the hypervisor. The hypercall should be invoked
only when the encryption attribute is changed from encrypted -> decrypted
and vice versa. By default all guest pages are considered encrypted.

The hypercall exits to userspace to manage the guest shared regions and
integrate with the userspace VMM's migration code.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <90778988e1ee01926ff9cac447aacb745f954c8c.1623174621.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 14:25:39 -04:00
Maxim Levitsky
6dba940352 KVM: x86: Introduce KVM_GET_SREGS2 / KVM_SET_SREGS2
This is a new version of KVM_GET_SREGS / KVM_SET_SREGS.

It has the following changes:
   * Has flags for future extensions
   * Has vcpu's PDPTRs, allowing to save/restore them on migration.
   * Lacks obsolete interrupt bitmap (done now via KVM_SET_VCPU_EVENTS)

New capability, KVM_CAP_SREGS2 is added to signal
the userspace of this ioctl.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210607090203.133058-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:47 -04:00
Vitaly Kuznetsov
644f706719 KVM: x86: hyper-v: Introduce KVM_CAP_HYPERV_ENFORCE_CPUID
Modeled after KVM_CAP_ENFORCE_PV_FEATURE_CPUID, the new capability allows
for limiting Hyper-V features to those exposed to the guest in Hyper-V
CPUIDs (0x40000003, 0x40000004, ...).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210521095204.2161214-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-17 13:09:38 -04:00
Mauro Carvalho Chehab
0a5fab9f08 docs: virt: api.rst: fix a pointer to SGX documentation
The document which describes the SGX kernel architecture was added at
commit 3fa97bf00126 ("Documentation/x86: Document SGX kernel architecture")

but the reference at virt/kvm/api.rst is pointing to some
non-existing document.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/138c24633c6e4edf862a2b4d77033c603fc10406.1621413933.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-20 13:44:14 -06:00
Siddharth Chandrasekaran
46a63924b0 doc/kvm: Fix wrong entry for KVM_CAP_X86_MSR_FILTER
The capability that exposes new ioctl KVM_X86_SET_MSR_FILTER to
userspace is specified incorrectly as the ioctl itself (instead of
KVM_CAP_X86_MSR_FILTER). This patch fixes it.

Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering")
Reviewed-by: Alexander Graf <graf@amazon.de>
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
Message-Id: <20210503120059.9283-1-sidcha@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-07 06:06:11 -04:00
Linus Torvalds
152d32aa84 ARM:
- Stage-2 isolation for the host kernel when running in protected mode
 
 - Guest SVE support when running in nVHE mode
 
 - Force W^X hypervisor mappings in nVHE mode
 
 - ITS save/restore for guests using direct injection with GICv4.1
 
 - nVHE panics now produce readable backtraces
 
 - Guest support for PTP using the ptp_kvm driver
 
 - Performance improvements in the S2 fault handler
 
 x86:
 
 - Optimizations and cleanup of nested SVM code
 
 - AMD: Support for virtual SPEC_CTRL
 
 - Optimizations of the new MMU code: fast invalidation,
   zap under read lock, enable/disably dirty page logging under
   read lock
 
 - /dev/kvm API for AMD SEV live migration (guest API coming soon)
 
 - support SEV virtual machines sharing the same encryption context
 
 - support SGX in virtual machines
 
 - add a few more statistics
 
 - improved directed yield heuristics
 
 - Lots and lots of cleanups
 
 Generic:
 
 - Rework of MMU notifier interface, simplifying and optimizing
 the architecture-specific code
 
 - Some selftests improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "This is a large update by KVM standards, including AMD PSP (Platform
  Security Processor, aka "AMD Secure Technology") and ARM CoreSight
  (debug and trace) changes.

  ARM:

   - CoreSight: Add support for ETE and TRBE

   - Stage-2 isolation for the host kernel when running in protected
     mode

   - Guest SVE support when running in nVHE mode

   - Force W^X hypervisor mappings in nVHE mode

   - ITS save/restore for guests using direct injection with GICv4.1

   - nVHE panics now produce readable backtraces

   - Guest support for PTP using the ptp_kvm driver

   - Performance improvements in the S2 fault handler

  x86:

   - AMD PSP driver changes

   - Optimizations and cleanup of nested SVM code

   - AMD: Support for virtual SPEC_CTRL

   - Optimizations of the new MMU code: fast invalidation, zap under
     read lock, enable/disably dirty page logging under read lock

   - /dev/kvm API for AMD SEV live migration (guest API coming soon)

   - support SEV virtual machines sharing the same encryption context

   - support SGX in virtual machines

   - add a few more statistics

   - improved directed yield heuristics

   - Lots and lots of cleanups

  Generic:

   - Rework of MMU notifier interface, simplifying and optimizing the
     architecture-specific code

   - a handful of "Get rid of oprofile leftovers" patches

   - Some selftests improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (379 commits)
  KVM: selftests: Speed up set_memory_region_test
  selftests: kvm: Fix the check of return value
  KVM: x86: Take advantage of kvm_arch_dy_has_pending_interrupt()
  KVM: SVM: Skip SEV cache flush if no ASIDs have been used
  KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids()
  KVM: SVM: Drop redundant svm_sev_enabled() helper
  KVM: SVM: Move SEV VMCB tracking allocation to sev.c
  KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup()
  KVM: SVM: Unconditionally invoke sev_hardware_teardown()
  KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported)
  KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y
  KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables
  KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features
  KVM: SVM: Move SEV module params/variables to sev.c
  KVM: SVM: Disable SEV/SEV-ES if NPT is disabled
  KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails
  KVM: SVM: Zero out the VMCB array used to track SEV ASID association
  x86/sev: Drop redundant and potentially misleading 'sev_enabled'
  KVM: x86: Move reverse CPUID helpers to separate header file
  KVM: x86: Rename GPR accessors to make mode-aware variants the defaults
  ...
2021-05-01 10:14:08 -07:00
Linus Torvalds
2f9ef0559e It's been a relatively busy cycle in docsland, though more than usually
well contained to Documentation/ itself.  Highlights include:
 
  - The Chinese translators have been busy and show no signs of stopping
    anytime soon.  Italian has also caught up.
 
  - Aditya Srivastava has been working on improvements to the kernel-doc
    script.
 
  - Thorsten continues his work on reporting-issues.rst and related
    documentation around regression reporting.
 
  - Lots of documentation updates, typo fixes, etc. as usual
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Merge tag 'docs-5.13' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle in docsland, though more than
  usually well contained to Documentation/ itself. Highlights include:

   - The Chinese translators have been busy and show no signs of
     stopping anytime soon. Italian has also caught up.

   - Aditya Srivastava has been working on improvements to the
     kernel-doc script.

   - Thorsten continues his work on reporting-issues.rst and related
     documentation around regression reporting.

   - Lots of documentation updates, typo fixes, etc. as usual"

* tag 'docs-5.13' of git://git.lwn.net/linux: (139 commits)
  docs/zh_CN: add openrisc translation to zh_CN index
  docs/zh_CN: add openrisc index.rst translation
  docs/zh_CN: add openrisc todo.rst translation
  docs/zh_CN: add openrisc openrisc_port.rst translation
  docs/zh_CN: add core api translation to zh_CN index
  docs/zh_CN: add core-api index.rst translation
  docs/zh_CN: add core-api irq index.rst translation
  docs/zh_CN: add core-api irq irqflags-tracing.rst translation
  docs/zh_CN: add core-api irq irq-domain.rst translation
  docs/zh_CN: add core-api irq irq-affinity.rst translation
  docs/zh_CN: add core-api irq concepts.rst translation
  docs: sphinx-pre-install: don't barf on beta Sphinx releases
  scripts: kernel-doc: improve parsing for kernel-doc comments syntax
  docs/zh_CN: two minor fixes in zh_CN/doc-guide/
  Documentation: dev-tools: Add Testing Overview
  docs/zh_CN: add translations in zh_CN/dev-tools/gcov
  docs: reporting-issues: make people CC the regressions list
  MAINTAINERS: add regressions mailing list
  doc:it_IT: align Italian documentation
  docs/zh_CN: sync reporting-issues.rst
  ...
2021-04-26 13:22:43 -07:00
Paolo Bonzini
f82762fb61 KVM: documentation: fix sphinx warnings
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-26 05:19:28 -04:00
Paolo Bonzini
c4f71901d5 KVM/arm64 updates for Linux 5.13
New features:
 
 - Stage-2 isolation for the host kernel when running in protected mode
 - Guest SVE support when running in nVHE mode
 - Force W^X hypervisor mappings in nVHE mode
 - ITS save/restore for guests using direct injection with GICv4.1
 - nVHE panics now produce readable backtraces
 - Guest support for PTP using the ptp_kvm driver
 - Performance improvements in the S2 fault handler
 - Alexandru is now a reviewer (not really a new feature...)
 
 Fixes:
 - Proper emulation of the GICR_TYPER register
 - Handle the complete set of relocation in the nVHE EL2 object
 - Get rid of the oprofile dependency in the PMU code (and of the
   oprofile body parts at the same time)
 - Debug and SPE fixes
 - Fix vcpu reset
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Merge tag 'kvmarm-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for Linux 5.13

New features:

- Stage-2 isolation for the host kernel when running in protected mode
- Guest SVE support when running in nVHE mode
- Force W^X hypervisor mappings in nVHE mode
- ITS save/restore for guests using direct injection with GICv4.1
- nVHE panics now produce readable backtraces
- Guest support for PTP using the ptp_kvm driver
- Performance improvements in the S2 fault handler
- Alexandru is now a reviewer (not really a new feature...)

Fixes:
- Proper emulation of the GICR_TYPER register
- Handle the complete set of relocation in the nVHE EL2 object
- Get rid of the oprofile dependency in the PMU code (and of the
  oprofile body parts at the same time)
- Debug and SPE fixes
- Fix vcpu reset
2021-04-23 07:41:17 -04:00
Paolo Bonzini
fd49e8ee70 Merge branch 'kvm-sev-cgroup' into HEAD 2021-04-22 13:19:01 -04:00
Nathan Tempelman
54526d1fd5 KVM: x86: Support KVM VMs sharing SEV context
Add a capability for userspace to mirror SEV encryption context from
one vm to another. On our side, this is intended to support a
Migration Helper vCPU, but it can also be used generically to support
other in-guest workloads scheduled by the host. The intention is for
the primary guest and the mirror to have nearly identical memslots.

The primary benefits of this are that:
1) The VMs do not share KVM contexts (think APIC/MSRs/etc), so they
can't accidentally clobber each other.
2) The VMs can have different memory-views, which is necessary for post-copy
migration (the migration vCPUs on the target need to read and write to
pages, when the primary guest would VMEXIT).

This does not change the threat model for AMD SEV. Any memory involved
is still owned by the primary guest and its initial state is still
attested to through the normal SEV_LAUNCH_* flows. If userspace wanted
to circumvent SEV, they could achieve the same effect by simply attaching
a vCPU to the primary VM.
This patch deliberately leaves userspace in charge of the memslots for the
mirror, as it already has the power to mess with them in the primary guest.

This patch does not support SEV-ES (much less SNP), as it does not
handle handing off attested VMSAs to the mirror.

For additional context, we need a Migration Helper because SEV PSP
migration is far too slow for our live migration on its own. Using
an in-guest migrator lets us speed this up significantly.

Signed-off-by: Nathan Tempelman <natet@google.com>
Message-Id: <20210408223214.2582277-1-natet@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-21 12:20:02 -04:00
Sean Christopherson
fe7e948837 KVM: x86: Add capability to grant VM access to privileged SGX attribute
Add a capability, KVM_CAP_SGX_ATTRIBUTE, that can be used by userspace
to grant a VM access to a priveleged attribute, with args[0] holding a
file handle to a valid SGX attribute file.

The SGX subsystem restricts access to a subset of enclave attributes to
provide additional security for an uncompromised kernel, e.g. to prevent
malware from using the PROVISIONKEY to ensure its nodes are running
inside a geniune SGX enclave and/or to obtain a stable fingerprint.

To prevent userspace from circumventing such restrictions by running an
enclave in a VM, KVM restricts guest access to privileged attributes by
default.

Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <0b099d65e933e068e3ea934b0523bab070cb8cea.1618196135.git.kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:56 -04:00
Emanuele Giuseppe Esposito
24e7475f93 doc/virt/kvm: move KVM_CAP_PPC_MULTITCE in section 8
KVM_CAP_PPC_MULTITCE is a capability, not an ioctl.
Therefore move it from section 4.97 to the new 8.31 (other capabilities).

To fill the gap, move KVM_X86_SET_MSR_FILTER (was 4.126) to
4.97, and shifted Xen-related ioctl (were 4.127 - 4.130) by
one place (4.126 - 4.129).

Also fixed minor typo in KVM_GET_MSR_INDEX_LIST ioctl description
(section 4.3).

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210316170814.64286-1-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-20 04:18:50 -04:00
Paolo Bonzini
8b13c36493 KVM: introduce KVM_CAP_SET_GUEST_DEBUG2
This capability will allow the user to know which KVM_GUESTDBG_* bits
are supported.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210401135451.1004564-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-17 08:31:02 -04:00
Marc Zyngier
d8f37d291c Merge branch 'kvm-arm64/ptp' into kvmarm-master/next
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-13 15:41:22 +01:00
Marc Zyngier
ad569b70aa Merge branch 'kvm-arm64/misc-5.13' into kvmarm-master/next
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-13 15:35:58 +01:00
Marc Zyngier
5b32a53d6d KVM: arm64: Clarify vcpu reset behaviour
Although the KVM_ARM_VCPU_INIT documentation mention that the
registers are reset to their "initial values", it doesn't
describe what these values are.

Describe this state explicitly.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-09 18:26:16 +01:00
Alexandru Elisei
feb5dc3de0 Documentation: KVM: Document KVM_GUESTDBG_USE_HW control flag for arm64
Commit 21b6f32f9471 ("KVM: arm64: guest debug, define API headers") added
the arm64 KVM_GUESTDBG_USE_HW flag for the KVM_SET_GUEST_DEBUG ioctl and
commit 834bf88726f0 ("KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG")
documented and implemented the flag functionality. Since its introduction,
at no point was the flag known by any name other than KVM_GUESTDBG_USE_HW
for the arm64 architecture, so refer to it as such in the documentation.

CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210407144857.199746-2-alexandru.elisei@arm.com
2021-04-07 16:40:02 +01:00
Jianyong Wu
3bf725699b KVM: arm64: Add support for the KVM PTP service
Implement the hypervisor side of the KVM PTP interface.

The service offers wall time and cycle count from host to guest.
The caller must specify whether they want the host's view of
either the virtual or physical counter.

Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com
2021-04-07 16:33:20 +01:00
Emanuele Giuseppe Esposito
9ce3746d64 documentation/kvm: additional explanations on KVM_SET_BOOT_CPU_ID
The ioctl KVM_SET_BOOT_CPU_ID fails when called after vcpu creation.
Add this explanation in the documentation.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210319091650.11967-1-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-19 05:31:32 -04:00
Sean Christopherson
b318e8decf KVM: x86: Protect userspace MSR filter with SRCU, and set atomically-ish
Fix a plethora of issues with MSR filtering by installing the resulting
filter as an atomic bundle instead of updating the live filter one range
at a time.  The KVM_X86_SET_MSR_FILTER ioctl() isn't truly atomic, as
the hardware MSR bitmaps won't be updated until the next VM-Enter, but
the relevant software struct is atomically updated, which is what KVM
really needs.

Similar to the approach used for modifying memslots, make arch.msr_filter
a SRCU-protected pointer, do all the work configuring the new filter
outside of kvm->lock, and then acquire kvm->lock only when the new filter
has been vetted and created.  That way vCPU readers either see the old
filter or the new filter in their entirety, not some half-baked state.

Yuan Yao pointed out a use-after-free in ksm_msr_allowed() due to a
TOCTOU bug, but that's just the tip of the iceberg...

  - Nothing is __rcu annotated, making it nigh impossible to audit the
    code for correctness.
  - kvm_add_msr_filter() has an unpaired smp_wmb().  Violation of kernel
    coding style aside, the lack of a smb_rmb() anywhere casts all code
    into doubt.
  - kvm_clear_msr_filter() has a double free TOCTOU bug, as it grabs
    count before taking the lock.
  - kvm_clear_msr_filter() also has memory leak due to the same TOCTOU bug.

The entire approach of updating the live filter is also flawed.  While
installing a new filter is inherently racy if vCPUs are running, fixing
the above issues also makes it trivial to ensure certain behavior is
deterministic, e.g. KVM can provide deterministic behavior for MSRs with
identical settings in the old and new filters.  An atomic update of the
filter also prevents KVM from getting into a half-baked state, e.g. if
installing a filter fails, the existing approach would leave the filter
in a half-baked state, having already committed whatever bits of the
filter were already processed.

[*] https://lkml.kernel.org/r/20210312083157.25403-1-yaoyuan0329os@gmail.com

Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering")
Cc: stable@vger.kernel.org
Cc: Alexander Graf <graf@amazon.com>
Reported-by: Yuan Yao <yaoyuan0329os@gmail.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210316184436.2544875-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-18 13:55:14 -04:00
Marc Zyngier
7d717558dd KVM: arm64: Reject VM creation when the default IPA size is unsupported
KVM/arm64 has forever used a 40bit default IPA space, partially
due to its 32bit heritage (where the only choice is 40bit).

However, there are implementations in the wild that have a *cough*
much smaller *cough* IPA space, which leads to a misprogramming of
VTCR_EL2, and a guest that is stuck on its first memory access
if userspace dares to ask for the default IPA setting (which most
VMMs do).

Instead, blundly reject the creation of such VM, as we can't
satisfy the requirements from userspace (with a one-off warning).
Also clarify the boot warning, and document that the VM creation
will fail when an unsupported IPA size is provided.

Although this is an ABI change, it doesn't really change much
for userspace:

- the guest couldn't run before this change, but no error was
  returned. At least userspace knows what is happening.

- a memory slot that was accepted because it did fit the default
  IPA space now doesn't even get a chance to be registered.

The other thing that is left doing is to convince userspace to
actually use the IPA space setting instead of relying on the
antiquated default.

Fixes: 233a7cb23531 ("kvm: arm64: Allow tuning the physical address size for VM")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20210311100016.3830038-2-maz@kernel.org
2021-03-12 15:42:57 +00:00
Jonathan Neuschäfer
c44456f296 docs: kvm: Fix a typo ("althought")
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20210301214722.2310911-1-j.neuschaefer@gmx.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-03-08 17:17:48 -07:00
David Woodhouse
30b5c851af KVM: x86/xen: Add support for vCPU runstate information
This is how Xen guests do steal time accounting. The hypervisor records
the amount of time spent in each of running/runnable/blocked/offline
states.

In the Xen accounting, a vCPU is still in state RUNSTATE_running while
in Xen for a hypercall or I/O trap, etc. Only if Xen explicitly schedules
does the state become RUNSTATE_blocked. In KVM this means that even when
the vCPU exits the kvm_run loop, the state remains RUNSTATE_running.

The VMM can explicitly set the vCPU to RUNSTATE_blocked by using the
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT attribute, and can also use
KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST to retrospectively add a given
amount of time to the blocked state and subtract it from the running
state.

The state_entry_time corresponds to get_kvmclock_ns() at the time the
vCPU entered the current state, and the total times of all four states
should always add up to state_entry_time.

Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20210301125309.874953-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-02 14:30:54 -05:00