43708 Commits

Author SHA1 Message Date
Paolo Bonzini
4a5fd41995 KVM SVM changes for 6.4:
- Add support for virtual NMIs
 
  - Fixes for edge cases related to virtual interrupts
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmRGuLISHHNlYW5qY0Bn
 b29nbGUuY29tAAoJEGCRIgFNDBL5NOMQAKy1Od54yzQsIKyAZZJVfOEm7N5VLQgz
 +jLilXgHd8dm/g0g/KVCDPFoZ/ut2Tf5Dn4WwyoPWOpgGsOyTwdDIJabf9rustkA
 goZFcfUXz+P1nangTidrj6CFYgGmVS13Uu//H19X4bSzT+YifVevJ4QkRVElj9Mh
 VBUeXppC/gMGBZ9tKEzl+AU3FwJ58cB88q4boovBFYiDdciv/fF86t02Lc+dCIX1
 6hTcOAnjAcp3eJY0wPQJUAEScufDKcMf6tSrsB/yWXv9KB9ANXFNXry8/+lW/Ux/
 oOUmUVdRXrrsRUqtYk9+KuMoIN7CL1SBV0RCm5ApqwqwnTVdHS+odHU3c2s7E/uU
 QXIW4vwSne3W9Y4YApDgFjwDwmzY85dvblWlWBnR2LW2I3Or48xK+S8LpWG+lj6l
 EDf7RzeqAipJ1qUq6qDYJlyg/YsyYlcoErtra423skg38HBWxQXdqkVIz3SYdKjA
 0OcBQIRI28KzJDn1gU6P3Q0Wr/cKsx9EGy6+jWBhf4Yf3eHP7+3WUTrg/Up0q8ny
 0j/+cbe5kBb6k2T9y2X6jm6TVbPV5FyMBOF/UxmqEbRLmxXjBe8tMnFwV+qN871I
 gk5HTSIkX39GU9kNA3h5HoWjdNeRfhazKR9ZVrELVc1zjHnGLthXBPZbIAUsPPMx
 vgM6jf8NwLXZ
 =9xNX
 -----END PGP SIGNATURE-----

Merge tag 'kvm-x86-svm-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.4:

 - Add support for virtual NMIs

 - Fixes for edge cases related to virtual interrupts
2023-04-26 15:56:27 -04:00
Paolo Bonzini
c21775ae02 KVM selftests, and an AMX/XCR0 bugfix, for 6.4:
- Don't advertisze XTILE_CFG in KVM_GET_SUPPORTED_CPUID if XTILE_DATA is
    not being reported due to userspace not opting in via prctl()
 
  - Overhaul the AMX selftests to improve coverage and cleanup the test
 
  - Misc cleanups
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmRGt50SHHNlYW5qY0Bn
 b29nbGUuY29tAAoJEGCRIgFNDBL5MskP/2PhSrdgHxCwfpqpdVe/q5OWwFuhn3wG
 f5QKMpEBg4wJFeIE3eGJEaDlg776nWtWDNgUmqdjoZ8vyyadkPX9CV2Y2Hq0M7Tw
 d0gKPjQrz2BavyDYoPNfs4pfshs4EvDTswBkhdAt8KTZhGZosJOywQIp61V3ePqr
 1rDP6C4+CmwTRAK0f7egslyJ2pZXiUcvhITvzx8XhIAQh6nEK4gUZ/l3hLmg38kD
 Af23kiLnP8lHUUx4BQtRAnTw0SZXJ8DcKtoFkzEH8mdj4g6EqXpxy48zuyZcqWVi
 4XIFr+WECPsV5gdqWN9rMDqIG2ib+2heKDmcdUptcVuvr1ktv0reQybmgVck4CKX
 fTAdu86/LBaQmIHwNHaNFPwdUby4QQZ8ajafPC62oc+B6N1lQg8bbCwnvO6KGlGl
 FaQTnzaZq7ft4tfQRXOMu1AbLZLK7dIqJHHhxR3MkBkd4MAcZ1bVKkvlJLqsOKNw
 TEsreXErY7AsegZK73Rn4IN/CJGBof5bZ2NIchmiN+0UfMsd9zGn66Als6oRNh4E
 tRUhFONPIEmydy9UB50qe6b98ElB6R++opZbvkVW2hy8lMy3iJrCvUbOs1nx3wbn
 cxvIuTfw/dAFf70S03/zudf7lYHs2wKV1rrIAebyTd4NnvWdVB8OaSHgZswMgVjb
 UzzQfnQ+u9so
 =BY10
 -----END PGP SIGNATURE-----

Merge tag 'kvm-x86-selftests-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM selftests, and an AMX/XCR0 bugfix, for 6.4:

 - 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()

 - Overhaul the AMX selftests to improve coverage and cleanup the test

 - Misc cleanups
2023-04-26 15:56:01 -04:00
Paolo Bonzini
48b1893ae3 KVM x86 PMU changes for 6.4:
- 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, and 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
 
  - Misc cleanups and fixes
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmRGtd4SHHNlYW5qY0Bn
 b29nbGUuY29tAAoJEGCRIgFNDBL5Z9kP/i3WZ40hevvQvB/5cEpxxmxYDwCYnnjM
 hiQgK5jT4SrMTmVjLgkNdI2PogQoS4CX+GC7lcA9bvse84hjuPvgOflb2B+p2UQi
 Ytbr9g/tfKNIpnKIk9mcPcSObN9vm2Kgt7n28rtPrHWj89eQzgc66eijqdpKBLxA
 c3crVR8krwYAQK0tmzHq1+H6hB369YbHAHyTTRRI/bNWnqKblnvUbt0NL2aBusa9
 rNMaOdRtinLpy2dmuX/b3japRB8QTnlf7zpPIF4cBEhbYXy5woClZpf1D2fCA6Er
 XFbEoYawMVd9UeJYbW4z5yErLT83eYoGp4U0eFXWp6fvh8nZlgCGvBKE9g4mmqwj
 aSLaTR5eVN2qlw6jXVeg3unCo8Eyl36AwYwve2L6sFmBvZvNV5iz2eQ7rrOe4oE3
 dnTUaLQ8I2SVg04MbYmCq5W+frTL/I7kqNpbccL1Z3R5WO4y5gz63mug6NfLIvhR
 t45TAIaifxBfcXQsBZM3v2KUK/xQrD3AbJmFKh54L2CKqiGaNWsMLX+6NZ7LZWgf
 8rEqsVkkQDgF7z8eXai4TR26nYfSX6g9gDqtOH73L87aJ7PJk5cRoDWQ1sWs1e/l
 4HA/L0Bo/3pnKAa0ZWxJOixmzqY49gNQf3dj8gt3jk3y2ijbAivshiSpPBmIxn0u
 QLeOf/LGvipl
 =m18F
 -----END PGP SIGNATURE-----

Merge tag 'kvm-x86-pmu-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM x86 PMU changes for 6.4:

 - 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, and 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

 - Misc cleanups and fixes
2023-04-26 15:53:36 -04:00
Paolo Bonzini
807b758496 KVM x86 MMU changes for 6.4:
- Tweak FNAME(sync_spte) to avoid unnecessary writes+flushes when the
    guest is only adding new PTEs
 
  - Overhaul .sync_page() and .invlpg() to share the .sync_page()
    implementation, i.e. 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()
 
  - Misc cleanups
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmRGsvASHHNlYW5qY0Bn
 b29nbGUuY29tAAoJEGCRIgFNDBL5XnoP/0D8rQmrA0xPHK81zYS1E71tsR/itO/T
 CQMSB4PhEqvcRUaWOuhLBRUW+noWzaOkjkMYK2uoPTdtme7v9+Ar7EtfrWYHrBWD
 IxHCAymo3a5dQPUc3Nb77u6HjRAOokPSqSz5jE4qAjlniW09feruro2Phi+BTme4
 JjxTc/7Oh0Fu26+mK7mJHiw3fV1x3YznnnRPrKGrVQes5L6ozNICkUZ6nvuJUVMk
 lTNHNQbG8PqJZnfWG7VIKRn1vdfXwEfnvyucGVEqFfPLkOXqJHyqMVmIOtvsH7C5
 l8j36+lBZwtFh2jk2EsXOTb6sS7l1MSvyHLlbaJaqqffP+77Hf1n0fROur0k9Yse
 jJJejJWxZ/SvjMt/bOA+4ybGafZH0lt20DsDWnat5GSQ1EVT1CInN2p8OY8pdecR
 QOJBqnNUOykC7/Pyad+IxTxwrOSNCYh+5aYG8AdGquZvNUEwjffVJqrmxDvklY8Z
 DTYwGKgNY7NsP/dV0WYYElsAuHiKwiDZL15KftiQebO1fPcZDpTzDo83/8UMfGxh
 yegngcNX9Qi7lWtLkUMy8A99UvejM0QrS/Zt8v1zjlQ8PjreZLLBWsNpe0ufIMRk
 31ZAC2OS4Koi3wZ54tA7Z1Kh11meGhAk5Ti7sNke0rDqB9UMmj6UKw121cSRvW7q
 W6O4U3YeGpKx
 =zb4u
 -----END PGP SIGNATURE-----

Merge tag 'kvm-x86-mmu-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM x86 MMU changes for 6.4:

 - Tweak FNAME(sync_spte) to avoid unnecessary writes+flushes when the
   guest is only adding new PTEs

 - Overhaul .sync_page() and .invlpg() to share the .sync_page()
   implementation, i.e. 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()

 - Misc cleanups
2023-04-26 15:50:01 -04:00
Paolo Bonzini
a1c288f87d 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
 
  - Misc cleanups
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCgAwFiEEMHr+pfEFOIzK+KY1YJEiAU0MEvkFAmRGr2sSHHNlYW5qY0Bn
 b29nbGUuY29tAAoJEGCRIgFNDBL5b80P/2ayACpc7iV2DysXkrxOdn1JmMu9BeHd
 3oMb7bydf79LMNAO+NKPqVjo74yZ/Lh8UyufJGgF3HnSCdumx5Iklyx6/2PUHu/I
 8xT1H7VlIGQMcNy0G4hMus34ZcafJl4y+BXgMEqEErLcy3n598UvFGJ+C0/4lnux
 2Gk7dLASHq/mVVKReBM/kD4RhCVy5Venz6zkk9KbwDLHAmfejVK5bSqDYAnO1WtV
 IBWetxlVyMZCnfPV2drhzgNVwiHvYvCaMBW+cUk5cH8Z2r0VZVDERmc1D4/rd04t
 xs9lMk6CdNU7REQfblA0xMgeO/dNAXq5Fs4FfcM8OTBZU32KKafPhgW1uj2Sv+9l
 nbb1XxZ7C0EcBhKVbUD6zRl05vjHwxlRgoi0yWUqERthFKNXHV42JJgaNn4fxDYS
 tOBKBNkM9z6tCGN2aZv6GwhsEyY2y7oLdbZUGK9/FM3mF1VBASms1BTwokJXTxCD
 pkOpAGeN5hxOlC4/wl6iHJTrz9oaJUj5E5kMD1oK6oQJgnnfqH0kVTG/ui/OUtJg
 8N3amYO/d7InFvuE0f9R6TqZVhTN2QefHmNJaEldsmYp1NMI8Ep8JIhQKRA2LZVE
 CGRxyrPj5CESerAItAI6tshEre5W8aScEzhpmd6HgHmahhQJsCEj+3q/J8FPWLG/
 iQ3GnggrklfU
 =qj7D
 -----END PGP SIGNATURE-----

Merge tag 'kvm-x86-misc-6.4' of https://github.com/kvm-x86/linux into HEAD

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

 - Misc cleanups
2023-04-26 15:49:23 -04:00
Paolo Bonzini
4f382a79a6 KVM/arm64 updates for 6.4
- 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.
 -----BEGIN PGP SIGNATURE-----
 
 iQJDBAABCgAtFiEEn9UcU+C1Yxj9lZw9I9DQutE9ekMFAmRCZIwPHG1hekBrZXJu
 ZWwub3JnAAoJECPQ0LrRPXpDoZ8P/ioXAdDbAE4hTuyD2YdKJ3IGWN3pg52Z7xc2
 rBXXFrbK9+n9FEc3AVdHoGsRPDP0Ynl+apj+aB0Klr/Fl0KKqac+W0ARX9rn1mI1
 HjeygFPaGnXjMUp0BjeSLS+g3b0gebELJ6R1QEe1/MIPb8Se7M1y3ZpMWdhe0PPL
 vyzw3LZq2OAlLgWKZhAfhh03qdr2kqJxypYs6nMrcexfn8dXT78dsYKW1nXmqKcE
 61Gg23MDPUoexYpUhm+ym5t8hltoI1di8faPmxEpaFzpSDyAg8V5vo6LiW9jn3cf
 RX0Sikk1laiRAhVbbIFCKC148vFyKxum3scpKyb91Qc+sK1kmIcxvEqlc6SfG9je
 +5ndZwAfXtW6SMSOyX8y5fXbee7M0sx3n3le9BNgwXfmLWg/GHXJ544dJgVIlf/e
 0Z+8QnP1IUDfARR/b2FlW7A7XLzNHQzO379ekcAdUptbGwlS9CrW6SJ83QR7K6fB
 bh0aSSELKsD7pX8wnNyNACvmz2zL12ITlDKdZWUr8MSxyTjgVy7s0BDsQT3sbrA1
 1sH++RvUWfC2k7tVT3vjZFzUDlPw3bnZmo5YMWRTMbXEdr1V5rDw5F5IXit13KeT
 8bk0hnJgnLmyoX2A17v5dkFMIKD7p13tqDRdfFcn0ru63HIKxgkS3ITkDmsAQELK
 DHT7RBE0
 =Bhta
 -----END PGP SIGNATURE-----

Merge tag 'kvmarm-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 6.4

- 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.
2023-04-26 15:46:52 -04:00
Marc Zyngier
6dcf7316e0 Merge branch kvm-arm64/smccc-filtering into kvmarm-master/next
* kvm-arm64/smccc-filtering:
  : .
  : SMCCC call filtering and forwarding to userspace, courtesy of
  : Oliver Upton. From the cover letter:
  :
  : "The Arm SMCCC is rather prescriptive in regards to the allocation of
  : SMCCC function ID ranges. Many of the hypercall ranges have an
  : associated specification from Arm (FF-A, PSCI, SDEI, etc.) with some
  : room for vendor-specific implementations.
  :
  : The ever-expanding SMCCC surface leaves a lot of work within KVM for
  : providing new features. Furthermore, KVM implements its own
  : vendor-specific ABI, with little room for other implementations (like
  : Hyper-V, for example). Rather than cramming it all into the kernel we
  : should provide a way for userspace to handle hypercalls."
  : .
  KVM: selftests: Fix spelling mistake "KVM_HYPERCAL_EXIT_SMC" -> "KVM_HYPERCALL_EXIT_SMC"
  KVM: arm64: Test that SMC64 arch calls are reserved
  KVM: arm64: Prevent userspace from handling SMC64 arch range
  KVM: arm64: Expose SMC/HVC width to userspace
  KVM: selftests: Add test for SMCCC filter
  KVM: selftests: Add a helper for SMCCC calls with SMC instruction
  KVM: arm64: Let errors from SMCCC emulation to reach userspace
  KVM: arm64: Return NOT_SUPPORTED to guest for unknown PSCI version
  KVM: arm64: Introduce support for userspace SMCCC filtering
  KVM: arm64: Add support for KVM_EXIT_HYPERCALL
  KVM: arm64: Use a maple tree to represent the SMCCC filter
  KVM: arm64: Refactor hvc filtering to support different actions
  KVM: arm64: Start handling SMCs from EL1
  KVM: arm64: Rename SMC/HVC call handler to reflect reality
  KVM: arm64: Add vm fd device attribute accessors
  KVM: arm64: Add a helper to check if a VM has ran once
  KVM: x86: Redefine 'longmode' as a flag for KVM_EXIT_HYPERCALL

Signed-off-by: Marc Zyngier <maz@kernel.org>
2023-04-21 09:44:32 +01:00
Sean Christopherson
55cd57b596 KVM: x86: Filter out XTILE_CFG if XTILE_DATA isn't permitted
Filter out XTILE_CFG from the supported XCR0 reported to userspace if the
current process doesn't have access to XTILE_DATA.  Attempting to set
XTILE_CFG in XCR0 will #GP if XTILE_DATA is also not set, and so keeping
XTILE_CFG as supported results in explosions if userspace feeds
KVM_GET_SUPPORTED_CPUID back into KVM and the guest doesn't sanity check
CPUID.

Fixes: 445ecdf79be0 ("kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID")
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Tested-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230405004520.421768-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-11 10:19:03 -07:00
Aaron Lewis
6be3ae45f5 KVM: x86: Add a helper to handle filtering of unpermitted XCR0 features
Add a helper, kvm_get_filtered_xcr0(), to dedup code that needs to account
for XCR0 features that require explicit opt-in on a per-process basis.  In
addition to documenting when KVM should/shouldn't consult
xstate_get_guest_group_perm(), the helper will also allow sanitizing the
filtered XCR0 to avoid enumerating architecturally illegal XCR0 values,
e.g. XTILE_CFG without XTILE_DATA.

No functional changes intended.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
[sean: rename helper, move to x86.h, massage changelog]
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Tested-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230405004520.421768-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-11 10:19:03 -07:00
Sean Christopherson
cf9f4c0eb1 KVM: x86/mmu: Refresh CR0.WP prior to checking for emulated permission faults
Refresh the MMU's snapshot of the vCPU's CR0.WP prior to checking for
permission faults when emulating a guest memory access and CR0.WP may be
guest owned.  If the guest toggles only CR0.WP and triggers emulation of
a supervisor write, e.g. when KVM is emulating UMIP, KVM may consume a
stale CR0.WP, i.e. use stale protection bits metadata.

Note, KVM passes through CR0.WP if and only if EPT is enabled as CR0.WP
is part of the MMU role for legacy shadow paging, and SVM (NPT) doesn't
support per-bit interception controls for CR0.  Don't bother checking for
EPT vs. NPT as the "old == new" check will always be true under NPT, i.e.
the only cost is the read of vcpu->arch.cr4 (SVM unconditionally grabs CR0
from the VMCB on VM-Exit).

Reported-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lkml.kernel.org/r/677169b4-051f-fcae-756b-9a3e1bb9f8fe%40grsecurity.net
Fixes: fb509f76acc8 ("KVM: VMX: Make CR0.WP a guest owned bit")
Tested-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20230405002608.418442-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-10 15:25:36 -07:00
Sean Christopherson
9ed3bf4112 KVM: x86/mmu: Move filling of Hyper-V's TLB range struct into Hyper-V code
Refactor Hyper-V's range-based TLB flushing API to take a gfn+nr_pages
pair instead of a struct, and bury said struct in Hyper-V specific code.

Passing along two params generates much better code for the common case
where KVM is _not_ running on Hyper-V, as forwarding the flush on to
Hyper-V's hv_flush_remote_tlbs_range() from kvm_flush_remote_tlbs_range()
becomes a tail call.

Cc: David Matlack <dmatlack@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20230405003133.419177-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-10 15:17:29 -07:00
Sean Christopherson
8a1300ff95 KVM: x86: Rename Hyper-V remote TLB hooks to match established scheme
Rename the Hyper-V hooks for TLB flushing to match the naming scheme used
by all the other TLB flushing hooks, e.g. in kvm_x86_ops, vendor code,
arch hooks from common code, etc.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20230405003133.419177-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-10 15:17:29 -07:00
Aaron Lewis
dfdeda67ea KVM: x86/pmu: Prevent the PMU from counting disallowed events
When counting "Instructions Retired" (0xc0) in a guest, KVM will
occasionally increment the PMU counter regardless of if that event is
being filtered. This is because some PMU events are incremented via
kvm_pmu_trigger_event(), which doesn't know about the event filter. Add
the event filter to kvm_pmu_trigger_event(), so events that are
disallowed do not increment their counters.

Fixes: 9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions")
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230307141400.1486314-2-aaronlewis@google.com
[sean: prepend "pmc" to the new function]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-07 09:24:16 -07:00
Like Xu
4fa5843d81 KVM: x86/pmu: Fix a typo in kvm_pmu_request_counter_reprogam()
Fix a "reprogam" => "reprogram" typo in kvm_pmu_request_counter_reprogam().

Fixes: 68fb4757e867 ("KVM: x86/pmu: Defer reprogram_counter() to kvm_pmu_handle_event()")
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230310113349.31799-1-likexu@tencent.com
[sean: trim the changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-07 09:07:41 -07:00
Like Xu
649bccd7fa KVM: x86/pmu: Rewrite reprogram_counters() to improve performance
A valid pmc is always tested before using pmu->reprogram_pmi. Eliminate
this part of the redundancy by setting the counter's bitmask directly,
and in addition, trigger KVM_REQ_PMU only once to save more cpu cycles.

Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230214050757.9623-4-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 16:04:31 -07:00
Sean Christopherson
8bca8c5ce4 KVM: VMX: Refactor intel_pmu_{g,}set_msr() to align with other helpers
Invert the flows in intel_pmu_{g,s}et_msr()'s case statements so that
they follow the kernel's preferred style of:

        if (<not valid>)
                return <error>

        <commit change>
        return <success>

which is also the style used by every other {g,s}et_msr() helper (except
AMD's PMU variant, which doesn't use a switch statement).

Modify the "set" paths with costly side effects, i.e. that reprogram
counters, to skip only the side effects, i.e. to perform reserved bits
checks even if the value is unchanged.  None of the reserved bits checks
are expensive, so there's no strong justification for skipping them, and
guarding only the side effect makes it slightly more obvious what is being
skipped and why.

No functional change intended (assuming no reserved bit bugs).

Link: https://lkml.kernel.org/r/Y%2B6cfen%2FCpO3%2FdLO%40google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 16:03:20 -07:00
Like Xu
cdd2fbf636 KVM: x86/pmu: Rename pmc_is_enabled() to pmc_is_globally_enabled()
The name of function pmc_is_enabled() is a bit misleading. A PMC can
be disabled either by PERF_CLOBAL_CTRL or by its corresponding EVTSEL.
Append global semantics to its name.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230214050757.9623-2-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 15:57:19 -07:00
Sean Christopherson
957d0f70e9 KVM: x86/pmu: Zero out LBR capabilities during PMU refresh
Zero out the LBR capabilities during PMU refresh to avoid exposing LBRs
to the guest against userspace's wishes. If userspace modifies the
guest's CPUID model or invokes KVM_CAP_PMU_CAPABILITY to disable vPMU
after an initial KVM_SET_CPUID2, but before the first KVM_RUN, KVM will
retain the previous LBR info due to bailing before refreshing the LBR
descriptor.

Note, this is a very theoretical bug, there is no known use case where a
VMM would deliberately enable the vPMU via KVM_SET_CPUID2, and then later
disable the vPMU.

Link: https://lore.kernel.org/r/20230311004618.920745-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:58:43 -07:00
Sean Christopherson
3a6de51a43 KVM: x86/pmu: WARN and bug the VM if PMU is refreshed after vCPU has run
Now that KVM disallows changing feature MSRs, i.e. PERF_CAPABILITIES,
after running a vCPU, WARN and bug the VM if the PMU is refreshed after
the vCPU has run.

Note, KVM has disallowed CPUID updates after running a vCPU since commit
feb627e8d6f6 ("KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN"), i.e.
PERF_CAPABILITIES was the only remaining way to trigger a PMU refresh
after KVM_RUN.

Cc: Like Xu <like.xu.linux@gmail.com>
Link: https://lore.kernel.org/r/20230311004618.920745-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:58:43 -07:00
Sean Christopherson
0094f62c7e KVM: x86: Disallow writes to immutable feature MSRs after KVM_RUN
Disallow writes to feature MSRs after KVM_RUN to prevent userspace from
changing the vCPU model after running the vCPU.  Similar to guest CPUID,
KVM uses feature MSRs to configure intercepts, determine what operations
are/aren't allowed, etc.  Changing the capabilities while the vCPU is
active will at best yield unpredictable guest behavior, and at worst
could be dangerous to KVM.

Allow writing the current value, e.g. so that userspace can blindly set
all MSRs when emulating RESET, and unconditionally allow writes to
MSR_IA32_UCODE_REV so that userspace can emulate patch loads.

Special case the VMX MSRs to keep the generic list small, i.e. so that
KVM can do a linear walk of the generic list without incurring meaningful
overhead.

Cc: Like Xu <like.xu.linux@gmail.com>
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:23 -07:00
Sean Christopherson
9eb6ba31db KVM: x86: Generate set of VMX feature MSRs using first/last definitions
Add VMX MSRs to the runtime list of feature MSRs by iterating over the
range of emulated MSRs instead of manually defining each MSR in the "all"
list.  Using the range definition reduces the cost of emulating a new VMX
MSR, e.g. prevents forgetting to add an MSR to the list.

Extracting the VMX MSRs from the "all" list, which is a compile-time
constant, also shrinks the list to the point where the compiler can
heavily optimize code that iterates over the list.

No functional change intended.

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:23 -07:00
Sean Christopherson
5757f5b956 KVM: x86: Add macros to track first...last VMX feature MSRs
Add macros to track the range of VMX feature MSRs that are emulated by
KVM to reduce the maintenance cost of extending the set of emulated MSRs.

Note, KVM doesn't necessarily emulate all known/consumed VMX MSRs, e.g.
PROCBASED_CTLS3 is consumed by KVM to enable IPI virtualization, but is
not emulated as KVM doesn't emulate/virtualize IPI virtualization for
nested guests.

No functional change intended.

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:22 -07:00
Sean Christopherson
fb3146b4dc KVM: x86: Add a helper to query whether or not a vCPU has ever run
Add a helper to query if a vCPU has run so that KVM doesn't have to open
code the check on last_vmentry_cpu being set to a magic value.

No functional change intended.

Suggested-by: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Like Xu <like.xu.linux@gmail.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:22 -07:00
Sean Christopherson
b1932c5c19 KVM: x86: Rename kvm_init_msr_list() to clarify it inits multiple lists
Rename kvm_init_msr_list() to kvm_init_msr_lists() to clarify that it
initializes multiple lists: MSRs to save, emulated MSRs, and feature MSRs.

No functional change intended.

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:22 -07:00
Sean Christopherson
400d213228 KVM: SVM: Return the local "r" variable from svm_set_msr()
Rename "r" to "ret" and actually return it from svm_set_msr() to reduce
the probability of repeating the mistake of commit 723d5fb0ffe4 ("kvm:
svm: Add IA32_FLUSH_CMD guest support"), which set "r" thinking that it
would be propagated to the caller.

Alternatively, the declaration of "r" could be moved into the handling of
MSR_TSC_AUX, but that risks variable shadowing in the future.  A wrapper
for kvm_set_user_return_msr() would allow eliding a local variable, but
that feels like delaying the inevitable.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:37 -04:00
Sean Christopherson
da3db168fb KVM: x86: Virtualize FLUSH_L1D and passthrough MSR_IA32_FLUSH_CMD
Virtualize FLUSH_L1D so that the guest can use the performant L1D flush
if one of the many mitigations might require a flush in the guest, e.g.
Linux provides an option to flush the L1D when switching mms.

Passthrough MSR_IA32_FLUSH_CMD for write when it's supported in hardware
and exposed to the guest, i.e. always let the guest write it directly if
FLUSH_L1D is fully supported.

Forward writes to hardware in host context on the off chance that KVM
ends up emulating a WRMSR, or in the really unlikely scenario where
userspace wants to force a flush.  Restrict these forwarded WRMSRs to
the known command out of an abundance of caution.  Passing through the
MSR means the guest can throw any and all values at hardware, but doing
so in host context is arguably a bit more dangerous.

Link: https://lkml.kernel.org/r/CALMp9eTt3xzAEoQ038bJQ9LN0ZOXrSWsN7xnNUD%2B0SS%3DWwF7Pg%40mail.gmail.com
Link: https://lore.kernel.org/all/20230201132905.549148-2-eesposit@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:37 -04:00
Sean Christopherson
903358c7ed KVM: x86: Move MSR_IA32_PRED_CMD WRMSR emulation to common code
Dedup the handling of MSR_IA32_PRED_CMD across VMX and SVM by moving the
logic to kvm_set_msr_common().  Now that the MSR interception toggling is
handled as part of setting guest CPUID, the VMX and SVM paths are
identical.

Opportunistically massage the code to make it a wee bit denser.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20230322011440.2195485-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:36 -04:00
Sean Christopherson
bff903e8cd KVM: SVM: Passthrough MSR_IA32_PRED_CMD based purely on host+guest CPUID
Passthrough MSR_IA32_PRED_CMD based purely on whether or not the MSR is
supported and enabled, i.e. don't wait until the first write.  There's no
benefit to deferred passthrough, and the extra logic only adds complexity.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:36 -04:00
Sean Christopherson
9a4c485013 KVM: VMX: Passthrough MSR_IA32_PRED_CMD based purely on host+guest CPUID
Passthrough MSR_IA32_PRED_CMD based purely on whether or not the MSR is
supported and enabled, i.e. don't wait until the first write.  There's no
benefit to deferred passthrough, and the extra logic only adds complexity.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20230322011440.2195485-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:36 -04:00
Sean Christopherson
52887af565 KVM: x86: Revert MSR_IA32_FLUSH_CMD.FLUSH_L1D enabling
Revert the recently added virtualizing of MSR_IA32_FLUSH_CMD, as both
the VMX and SVM are fatally buggy to guests that use MSR_IA32_FLUSH_CMD or
MSR_IA32_PRED_CMD, and because the entire foundation of the logic is
flawed.

The most immediate problem is an inverted check on @cmd that results in
rejecting legal values.  SVM doubles down on bugs and drops the error,
i.e. silently breaks all guest mitigations based on the command MSRs.

The next issue is that neither VMX nor SVM was updated to mark
MSR_IA32_FLUSH_CMD as being a possible passthrough MSR,
which isn't hugely problematic, but does break MSR filtering and triggers
a WARN on VMX designed to catch this exact bug.

The foundational issues stem from the MSR_IA32_FLUSH_CMD code reusing
logic from MSR_IA32_PRED_CMD, which in turn was likely copied from KVM's
support for MSR_IA32_SPEC_CTRL.  The copy+paste from MSR_IA32_SPEC_CTRL
was misguided as MSR_IA32_PRED_CMD (and MSR_IA32_FLUSH_CMD) is a
write-only MSR, i.e. doesn't need the same "deferred passthrough"
shenanigans as MSR_IA32_SPEC_CTRL.

Revert all MSR_IA32_FLUSH_CMD enabling in one fell swoop so that there is
no point where KVM advertises, but does not support, L1D_FLUSH.

This reverts commits 45cf86f26148e549c5ba4a8ab32a390e4bde216e,
723d5fb0ffe4c02bd4edf47ea02c02e454719f28, and
a807b78ad04b2eaa348f52f5cc7702385b6de1ee.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lkml.kernel.org/r/20230317190432.GA863767%40dev-arch.thelio-3990X
Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Mathias Krause <minipli@grsecurity.net>
Message-Id: <20230322011440.2195485-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:35 -04:00
Sean Christopherson
098f4c061e KVM: x86/pmu: Disallow legacy LBRs if architectural LBRs are available
Disallow enabling LBR support if the CPU supports architectural LBRs.
Traditional LBR support is absent on CPU models that have architectural
LBRs, and KVM doesn't yet support arch LBRs, i.e. KVM will pass through
non-existent MSRs if userspace enables LBRs for the guest.

Cc: stable@vger.kernel.org
Cc: Yang Weijiang <weijiang.yang@intel.com>
Cc: Like Xu <like.xu.linux@gmail.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Fixes: be635e34c284 ("KVM: vmx/pmu: Expose LBR_FMT in the MSR_IA32_PERF_CAPABILITIES")
Tested-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230128001427.2548858-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-05 17:00:17 -07:00
Tom Rix
944a8dad8b KVM: x86: set "mitigate_smt_rsb" storage-class-specifier to static
smatch reports
arch/x86/kvm/x86.c:199:20: warning: symbol
  'mitigate_smt_rsb' was not declared. Should it be static?

This variable is only used in one file so it should be static.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230404010141.1913667-1-trix@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-05 16:47:35 -07:00
Like Xu
7e768ce827 KVM: x86/pmu: Zero out pmu->all_valid_pmc_idx each time it's refreshed
The kvm_pmu_refresh() may be called repeatedly (e.g. configure guest
CPUID repeatedly or update MSR_IA32_PERF_CAPABILITIES) and each
call will use the last pmu->all_valid_pmc_idx value, with the residual
bits introducing additional overhead later in the vPMU emulation.

Fixes: b35e5548b411 ("KVM: x86/vPMU: Add lazy mechanism to release perf_event per vPMC")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230404071759.75376-1-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-05 16:33:10 -07:00
Oliver Upton
e65733b5c5 KVM: x86: Redefine 'longmode' as a flag for KVM_EXIT_HYPERCALL
The 'longmode' field is a bit annoying as it blows an entire __u32 to
represent a boolean value. Since other architectures are looking to add
support for KVM_EXIT_HYPERCALL, now is probably a good time to clean it
up.

Redefine the field (and the remaining padding) as a set of flags.
Preserve the existing ABI by using bit 0 to indicate if the guest was in
long mode and requiring that the remaining 31 bits must be zero.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230404154050.2270077-2-oliver.upton@linux.dev
2023-04-05 12:07:41 +01:00
Vipin Sharma
40fa907e5a KVM: x86/mmu: Merge all handle_changed_pte*() functions
Merge __handle_changed_pte() and handle_changed_spte_acc_track() into a
single function, handle_changed_pte(), as the two are always used
together.  Remove the existing handle_changed_pte(), as it's just a
wrapper that calls __handle_changed_pte() and
handle_changed_spte_acc_track().

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:31 -07:00
Vipin Sharma
1f9973456e KVM: x86/mmu: Remove handle_changed_spte_dirty_log()
Remove handle_changed_spte_dirty_log() as there is no code flow which
sets 4KiB SPTE writable and hit this path. This function marks the page
dirty in a memslot only if new SPTE is 4KiB in size and writable.

Current users of handle_changed_spte_dirty_log() are:
1. set_spte_gfn() - Create only non writable SPTEs.
2. write_protect_gfn() - Change an SPTE to non writable.
3. zap leaf and roots APIs - Everything is 0.
4. handle_removed_pt() - Sets SPTEs to REMOVED_SPTE
5. tdp_mmu_link_sp() - Makes non leaf SPTEs.

There is also no path which creates a writable 4KiB without going
through make_spte() and this functions takes care of marking SPTE dirty
in the memslot if it is PT_WRITABLE.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: add blurb to __handle_changed_spte()'s comment]
Link: https://lore.kernel.org/r/20230321220021.2119033-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
0b7cc2547d KVM: x86/mmu: Remove "record_acc_track" in __tdp_mmu_set_spte()
Remove bool parameter "record_acc_track" from __tdp_mmu_set_spte() and
refactor the code. This variable is always set to true by its caller.

Remove single and double underscore prefix from tdp_mmu_set_spte()
related APIs:
1. Change __tdp_mmu_set_spte() to tdp_mmu_set_spte()
2. Change _tdp_mmu_set_spte() to tdp_mmu_iter_set_spte()

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20230321220021.2119033-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
891f115960 KVM: x86/mmu: Bypass __handle_changed_spte() when aging TDP MMU SPTEs
Drop everything except the "tdp_mmu_spte_changed" tracepoint part of
__handle_changed_spte() when aging SPTEs in the TDP MMU, as clearing the
accessed status doesn't affect the SPTE's shadow-present status, whether
or not the SPTE is a leaf, or change the PFN.  I.e. none of the functional
updates handled by __handle_changed_spte() are relevant.

Losing __handle_changed_spte()'s sanity checks does mean that a bug could
theoretical go unnoticed, but that scenario is extremely unlikely, e.g.
would effectively require a misconfigured MMU or a locking bug elsewhere.

Link: https://lore.kernel.org/all/Y9HcHRBShQgjxsQb@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
6141df067d KVM: x86/mmu: Drop unnecessary dirty log checks when aging TDP MMU SPTEs
Drop the unnecessary call to handle dirty log updates when aging TDP MMU
SPTEs, as neither clearing the Accessed bit nor marking a SPTE for access
tracking can _set_ the Writable bit, i.e. can't trigger marking a gfn
dirty in its memslot.  The access tracking path can _clear_ the Writable
bit, e.g. if the XCHG races with fast_page_fault() and writes the stale
value without the Writable bit set, but clearing the Writable bit outside
of mmu_lock is not allowed, i.e. access tracking can't spuriously set the
Writable bit.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
[sean: split to separate patch, apply to dirty path, write changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
7ee131e3a3 KVM: x86/mmu: Clear only A-bit (if enabled) when aging TDP MMU SPTEs
Use tdp_mmu_clear_spte_bits() when clearing the Accessed bit in TDP MMU
SPTEs so as to use an atomic-AND instead of XCHG to clear the A-bit.
Similar to the D-bit story, this will allow KVM to bypass
__handle_changed_spte() by ensuring only the A-bit is modified.

Link: https://lore.kernel.org/all/Y9HcHRBShQgjxsQb@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: massage changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
e73008705d KVM: x86/mmu: Remove "record_dirty_log" in __tdp_mmu_set_spte()
Remove bool parameter "record_dirty_log" from __tdp_mmu_set_spte() and
refactor the code as this variable is always set to true by its caller.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20230321220021.2119033-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
1e0f42985f KVM: x86/mmu: Bypass __handle_changed_spte() when clearing TDP MMU dirty bits
Drop everything except marking the PFN dirty and the relevant tracepoint
parts of __handle_changed_spte() when clearing the dirty status of gfns in
the TDP MMU.  Clearing only the Dirty (or Writable) bit doesn't affect
the SPTEs shadow-present status, whether or not the SPTE is a leaf, or
change the SPTE's PFN.  I.e. other than marking the PFN dirty, none of the
functional updates handled by __handle_changed_spte() are relevant.

Losing __handle_changed_spte()'s sanity checks does mean that a bug could
theoretical go unnoticed, but that scenario is extremely unlikely, e.g.
would effectively require a misconfigured or a locking bug elsewhere.

Opportunistically remove a comment blurb from __handle_changed_spte()
about all modifications to TDP MMU SPTEs needing to invoke said function,
that "rule" hasn't been true since fast page fault support was added for
the TDP MMU (and perhaps even before).

Tested on a VM (160 vCPUs, 160 GB memory) and found that performance of
clear dirty log stage improved by ~40% in dirty_log_perf_test (with the
full optimization applied).

Before optimization:
--------------------
Iteration 1 clear dirty log time: 3.638543593s
Iteration 2 clear dirty log time: 3.145032742s
Iteration 3 clear dirty log time: 3.142340358s
Clear dirty log over 3 iterations took 9.925916693s. (Avg 3.308638897s/iteration)

After optimization:
-------------------
Iteration 1 clear dirty log time: 2.318988110s
Iteration 2 clear dirty log time: 1.794470164s
Iteration 3 clear dirty log time: 1.791668628s
Clear dirty log over 3 iterations took 5.905126902s. (Avg 1.968375634s/iteration)

Link: https://lore.kernel.org/all/Y9hXmz%2FnDOr1hQal@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: split the switch to atomic-AND to a separate patch]
Link: https://lore.kernel.org/r/20230321220021.2119033-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
cf05e8c732 KVM: x86/mmu: Drop access tracking checks when clearing TDP MMU dirty bits
Drop the unnecessary call to handle access-tracking changes when clearing
the dirty status of TDP MMU SPTEs.  Neither the Dirty bit nor the Writable
bit has any impact on the accessed state of a page, i.e. clearing only
the aforementioned bits doesn't make an accessed SPTE suddently not
accessed.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
[sean: split to separate patch, write changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
89c313f20c KVM: x86/mmu: Atomically clear SPTE dirty state in the clear-dirty-log flow
Optimize the clearing of dirty state in TDP MMU SPTEs by doing an
atomic-AND (on SPTEs that have volatile bits) instead of the full XCHG
that currently ends up being invoked (see kvm_tdp_mmu_write_spte()).
Clearing _only_ the bit in question will allow KVM to skip the many
irrelevant checks in __handle_changed_spte() by avoiding any collateral
damage due to the XCHG writing all SPTE bits, e.g. the XCHG could race
with fast_page_fault() setting the W-bit and the CPU setting the D-bit,
and thus incorrectly drop the CPU's D-bit update.

Link: https://lore.kernel.org/all/Y9hXmz%2FnDOr1hQal@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
[sean: split the switch to atomic-AND to a separate patch]
Link: https://lore.kernel.org/r/20230321220021.2119033-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
697c89bed9 KVM: x86/mmu: Consolidate Dirty vs. Writable clearing logic in TDP MMU
Deduplicate the guts of the TDP MMU's clearing of dirty status by
snapshotting whether to check+clear the Dirty bit vs. the Writable bit,
which is the only difference between the two flavors of dirty tracking.

Note, kvm_ad_enabled() is just a wrapper for shadow_accessed_mask, i.e.
is constant after kvm-{intel,amd}.ko is loaded.

Link: https://lore.kernel.org/all/Yz4Qi7cn7TWTWQjj@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
[sean: split to separate patch, apply to dirty log, write changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
5982a53926 KVM: x86/mmu: Use kvm_ad_enabled() to determine if TDP MMU SPTEs need wrprot
Use the constant-after-module-load kvm_ad_enabled() to check if SPTEs in
the TDP MMU need to be write-protected when clearing accessed/dirty status
instead of manually checking every SPTE.  The per-SPTE A/D enabling is
specific to nested EPT MMUs, i.e. when KVM is using EPT A/D bits but L1 is
not, and so cannot happen in the TDP MMU (which is non-nested only).

Keep the original code as sanity checks buried under MMU_WARN_ON().
MMU_WARN_ON() is more or less useless at the moment, but there are plans
to change that.

Link: https://lore.kernel.org/all/Yz4Qi7cn7TWTWQjj@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
[sean: split to separate patch, apply to dirty path, write changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Vipin Sharma
41e07665f1 KVM: x86/mmu: Add a helper function to check if an SPTE needs atomic write
Move conditions in kvm_tdp_mmu_write_spte() to check if an SPTE should
be written atomically or not to a separate function.

This new function, kvm_tdp_mmu_spte_need_atomic_write(),  will be used
in future commits to optimize clearing bits in SPTEs.

Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Link: https://lore.kernel.org/r/20230321220021.2119033-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 12:37:30 -07:00
Xinghui Li
c0d0ce9b5a KVM: SVM: Remove a duplicate definition of VMCB_AVIC_APIC_BAR_MASK
VMCB_AVIC_APIC_BAR_MASK is defined twice with the same value in svm.h,
which is meaningless. Delete the duplicate one.

Fixes: 391503528257 ("KVM: x86: SVM: move avic definitions from AMD's spec to svm.h")
Signed-off-by: Xinghui Li <korantli@tencent.com>
Reviewed-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230403095200.1391782-1-korantwork@gmail.com
[sean: tweak shortlog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-04 11:08:12 -07:00
Linus Torvalds
974fc94336 - Properly clear perf event status tracking in the AMD perf event
overflow handler
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmQgQDAACgkQEsHwGGHe
 VUo1OA//YfWLXnc9CBN1S8EefXj0oHHogj3jkVMQLfWOoYmaknaXIHsOg8g4Kihs
 liUZO0tGWD4WdiUe/GpWmC0KIMtuZ8I1o0ML7LLdxpfexZbMLdlaqUHO68rlHDXt
 /nJ1mmcA3MJTkdDePIjpI1b8TM+4L8XWzi4XRxMXVbhquuQXGkcqWacq0/rh/0et
 /5iqzp88varuAwSHTrmX12keYEtRLsfL8+fy5WdQX7L9i1oiSU41IsZ95/wMmjbE
 +Y7t/EFKiIVH9+JdeM78HLAem+hIXZByNay6E6p+SveNtcjW1QRVviQ+QZ+c71hh
 0PQgeuJzArd0NRG7TWLUktCuONj6LZZ7E3apQyzXTPcg6H/IX9JeQv1dR9UGyjx7
 mAyrCSS9KzPiydiQLGlOQJeXCRwlNbo7fJKfX/uiCYErEhokQXztbLdHV3G/J/4v
 nuBQ2t50ZYLWbQoTZ8IOncrwTgDw7lSU8opNaE6G3P8Ut7BXy3f55YMRwKLg0WO7
 9X9AYhCMCtUeLwrTHX1SwPZToDI0huCJNTPy94ioSpGSU951CvgXCzX/ZPOsAFjs
 ndw3TQlI3xDGJETa2Q1fev08UjSHOieFlX5MQ+zLSIf6cSy4s7DeeOOBLXZouKnc
 jTx+31U1lhGTsqb43ac18CNjpslu67GnyCpzMjy3UymohQzV/nE=
 =dK66
 -----END PGP SIGNATURE-----

Merge tag 'perf_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fix from Borislav Petkov:

 - Properly clear perf event status tracking in the AMD perf event
   overflow handler

* tag 'perf_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd/core: Always clear status for idx
2023-03-26 09:13:35 -07:00
Linus Torvalds
986c63741d - Add a AMX ptrace self test
- Prevent a false-positive warning when retrieving the (invalid) address of
   dynamic FPU features in their init state which are not saved in
   init_fpstate at all
 
 - Randomize per-CPU entry areas only when KASLR is enabled
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmQgPFAACgkQEsHwGGHe
 VUrAfA//QyZE5JnH0Ber3upRlZ/dPSNKIaOX6DMLshGj7QDqs2utTnjc4pwaqGWD
 OWpPuAJvOo2+NsN4nfB12venasIzseXDBBhEw6a5kYx73QmFbZ4XswFBLl2Eh8we
 cFbqU4B8SQvFQaahZ4kRRHpsmNGEPYRvgh2lBjcKUJBUaCuu6KoqE9+I3t173Obc
 sPfkXmhintDjYIjKfllN78rsBq4uCCaOVu5u299ZFMdBakRtx0M7U3547+4hwoE3
 txP+VK+TPs8e64XJtCTem1br8HXNt/W5pC4IoQPnH8V+FLhUp1iIz6FpVHnJ7VMD
 9c8VL7e8BNXhKkQn8sSkSVUZV3xNP7n4MbKKbba3f6EWPZnI28WQ3w09LUte/1aa
 hHEHyjMVyJfUiAcfuE1gZflG1+TqT8GkQJ+hqG9+/iSCWftOMuhfsKCROCLGhltJ
 yYBoyR2ZC1ErSLIOvgYAEUIeZ9FkzreOU0Pit6P/5qaPu+EXw3uDzoZB0WQH40Z5
 PQwz04/s3idPwbfCZDOyNc7QZwxbGu1ESkdiTtCJmbBLW0MkWiBCnf/qZsK7PdD1
 Q2qmx86ewIo6QipJpGK9pqWuzwFYNEJJHn3P7T1CcYQnQb+61m+b6WeYozQCgyMF
 0dII6JulW98/WzjVgH6zUA0a0dicO7FM9H6iEGqlIcvxv0PuM7M=
 =eZTj
 -----END PGP SIGNATURE-----

Merge tag 'x86_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Add a AMX ptrace self test

 - Prevent a false-positive warning when retrieving the (invalid)
   address of dynamic FPU features in their init state which are not
   saved in init_fpstate at all

 - Randomize per-CPU entry areas only when KASLR is enabled

* tag 'x86_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  selftests/x86/amx: Add a ptrace test
  x86/fpu/xstate: Prevent false-positive warning in __copy_xstate_uabi_buf()
  x86/mm: Do not shuffle CPU entry areas without KASLR
2023-03-26 09:01:24 -07:00