* Rework almost all of KVM's exports to expose symbols only to KVM's x86
vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko.
x86:
* Rework almost all of KVM x86's exports to expose symbols only to KVM's
vendor modules, i.e. to kvm-{amd,intel}.ko.
* Add support for virtualizing Control-flow Enforcement Technology (CET) on
Intel (Shadow Stacks and Indirect Branch Tracking) and AMD (Shadow Stacks).
It's worth noting that while SHSTK and IBT can be enabled separately in CPUID,
it is not really possible to virtualize them separately. Therefore, Intel
processors will really allow both SHSTK and IBT under the hood if either is
made visible in the guest's CPUID. The alternative would be to intercept
XSAVES/XRSTORS, which is not feasible for performance reasons.
* Fix a variety of fuzzing WARNs all caused by checking L1 intercepts when
completing userspace I/O. KVM has already committed to allowing L2 to
to perform I/O at that point.
* Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the MSR is
supposed to exist for v2 PMUs.
* Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs.
* Add support for the immediate forms of RDMSR and WRMSRNS, sans full
emulator support (KVM should never need to emulate the MSRs outside of
forced emulation and other contrived testing scenarios).
* Clean up the MSR APIs in preparation for CET and FRED virtualization, as
well as mediated vPMU support.
* Clean up a pile of PMU code in anticipation of adding support for mediated
vPMUs.
* Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI vmexits
needed to faithfully emulate an I/O APIC for such guests.
* Many cleanups and minor fixes.
* Recover possible NX huge pages within the TDP MMU under read lock to
reduce guest jitter when restoring NX huge pages.
* Return -EAGAIN during prefault if userspace concurrently deletes/moves the
relevant memslot, to fix an issue where prefaulting could deadlock with the
memslot update.
x86 (AMD):
* Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is supported.
* Require a minimum GHCB version of 2 when starting SEV-SNP guests via
KVM_SEV_INIT2 so that invalid GHCB versions result in immediate errors
instead of latent guest failures.
* Add support for SEV-SNP's CipherText Hiding, an opt-in feature that prevents
unauthorized CPU accesses from reading the ciphertext of SNP guest private
memory, e.g. to attempt an offline attack. This feature splits the shared
SEV-ES/SEV-SNP ASID space into separate ranges for SEV-ES and SEV-SNP guests,
therefore a new module parameter is needed to control the number of ASIDs
that can be used for VMs with CipherText Hiding vs. how many can be used to
run SEV-ES guests.
* Add support for Secure TSC for SEV-SNP guests, which prevents the untrusted
host from tampering with the guest's TSC frequency, while still allowing the
the VMM to configure the guest's TSC frequency prior to launch.
* Validate the XCR0 provided by the guest (via the GHCB) to avoid bugs
resulting from bogus XCR0 values.
* Save an SEV guest's policy if and only if LAUNCH_START fully succeeds to
avoid leaving behind stale state (thankfully not consumed in KVM).
* Explicitly reject non-positive effective lengths during SNP's LAUNCH_UPDATE
instead of subtly relying on guest_memfd to deal with them.
* Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the host's
desired TSC_AUX, to fix a bug where KVM was keeping a different vCPU's
TSC_AUX in the host MSR until return to userspace.
KVM (Intel):
* Preparation for FRED support.
* Don't retry in TDX's anti-zero-step mitigation if the target memslot is
invalid, i.e. is being deleted or moved, to fix a deadlock scenario similar
to the aforementioned prefaulting case.
* Misc bugfixes and minor cleanups.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull x86 kvm updates from Paolo Bonzini:
"Generic:
- Rework almost all of KVM's exports to expose symbols only to KVM's
x86 vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko
x86:
- Rework almost all of KVM x86's exports to expose symbols only to
KVM's vendor modules, i.e. to kvm-{amd,intel}.ko
- Add support for virtualizing Control-flow Enforcement Technology
(CET) on Intel (Shadow Stacks and Indirect Branch Tracking) and AMD
(Shadow Stacks).
It is worth noting that while SHSTK and IBT can be enabled
separately in CPUID, it is not really possible to virtualize them
separately. Therefore, Intel processors will really allow both
SHSTK and IBT under the hood if either is made visible in the
guest's CPUID. The alternative would be to intercept
XSAVES/XRSTORS, which is not feasible for performance reasons
- Fix a variety of fuzzing WARNs all caused by checking L1 intercepts
when completing userspace I/O. KVM has already committed to
allowing L2 to to perform I/O at that point
- Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the
MSR is supposed to exist for v2 PMUs
- Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs
- Add support for the immediate forms of RDMSR and WRMSRNS, sans full
emulator support (KVM should never need to emulate the MSRs outside
of forced emulation and other contrived testing scenarios)
- Clean up the MSR APIs in preparation for CET and FRED
virtualization, as well as mediated vPMU support
- Clean up a pile of PMU code in anticipation of adding support for
mediated vPMUs
- Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI
vmexits needed to faithfully emulate an I/O APIC for such guests
- Many cleanups and minor fixes
- Recover possible NX huge pages within the TDP MMU under read lock
to reduce guest jitter when restoring NX huge pages
- Return -EAGAIN during prefault if userspace concurrently
deletes/moves the relevant memslot, to fix an issue where
prefaulting could deadlock with the memslot update
x86 (AMD):
- Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is
supported
- Require a minimum GHCB version of 2 when starting SEV-SNP guests
via KVM_SEV_INIT2 so that invalid GHCB versions result in immediate
errors instead of latent guest failures
- Add support for SEV-SNP's CipherText Hiding, an opt-in feature that
prevents unauthorized CPU accesses from reading the ciphertext of
SNP guest private memory, e.g. to attempt an offline attack. This
feature splits the shared SEV-ES/SEV-SNP ASID space into separate
ranges for SEV-ES and SEV-SNP guests, therefore a new module
parameter is needed to control the number of ASIDs that can be used
for VMs with CipherText Hiding vs. how many can be used to run
SEV-ES guests
- Add support for Secure TSC for SEV-SNP guests, which prevents the
untrusted host from tampering with the guest's TSC frequency, while
still allowing the the VMM to configure the guest's TSC frequency
prior to launch
- Validate the XCR0 provided by the guest (via the GHCB) to avoid
bugs resulting from bogus XCR0 values
- Save an SEV guest's policy if and only if LAUNCH_START fully
succeeds to avoid leaving behind stale state (thankfully not
consumed in KVM)
- Explicitly reject non-positive effective lengths during SNP's
LAUNCH_UPDATE instead of subtly relying on guest_memfd to deal with
them
- Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the
host's desired TSC_AUX, to fix a bug where KVM was keeping a
different vCPU's TSC_AUX in the host MSR until return to userspace
KVM (Intel):
- Preparation for FRED support
- Don't retry in TDX's anti-zero-step mitigation if the target
memslot is invalid, i.e. is being deleted or moved, to fix a
deadlock scenario similar to the aforementioned prefaulting case
- Misc bugfixes and minor cleanups"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
KVM: x86: Export KVM-internal symbols for sub-modules only
KVM: x86: Drop pointless exports of kvm_arch_xxx() hooks
KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c
KVM: Export KVM-internal symbols for sub-modules only
KVM: s390/vfio-ap: Use kvm_is_gpa_in_memslot() instead of open coded equivalent
KVM: VMX: Make CR4.CET a guest owned bit
KVM: selftests: Verify MSRs are (not) in save/restore list when (un)supported
KVM: selftests: Add coverage for KVM-defined registers in MSRs test
KVM: selftests: Add KVM_{G,S}ET_ONE_REG coverage to MSRs test
KVM: selftests: Extend MSRs test to validate vCPUs without supported features
KVM: selftests: Add support for MSR_IA32_{S,U}_CET to MSRs test
KVM: selftests: Add an MSR test to exercise guest/host and read/write
KVM: x86: Define AMD's #HV, #VC, and #SX exception vectors
KVM: x86: Define Control Protection Exception (#CP) vector
KVM: x86: Add human friendly formatting for #XM, and #VE
KVM: SVM: Enable shadow stack virtualization for SVM
KVM: SEV: Synchronize MSR_IA32_XSS from the GHCB when it's valid
KVM: SVM: Pass through shadow stack MSRs as appropriate
KVM: SVM: Update dump_vmcb with shadow stack save area additions
KVM: nSVM: Save/load CET Shadow Stack state to/from vmcb12/vmcb02
...
256e341706