Re: [GIT PULL] KVM: x86: Misc changes for 7.2

[Paolo Bonzini]

On Fri, Jun 12, 2026 at 2:48 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> By patch count, the register API cleanup dominates, but the most notable change
> here is the SNP and TDX hypercall return code handling from Vishal+Sagi.  To
> allow userspace to tell the guest to "retry", the changes interpret the return
> code from userspace as an errno value, and explicitly recognize only EAGAIN and
> EINVAL.  All other errnos are now reserved.  This is a change in uABI, but as
> far as we know, it won't break any VMMs that support SNP or TDX
>
> The following changes since commit b7fbe9a1bf9ee6c967ef77d366ca58c35fcf1887:
>
>   Merge branch 'kvm-apx-prepare' into HEAD (2026-05-13 12:38:31 -0400)
>
> are available in the Git repository at:
>
>   https://github.com/kvm-x86/linux.git tags/kvm-x86-misc-7.2
>
> for you to fetch changes up to 65aa483f32ec674f0506658329d43403cafe5eb0:
>
>   Documentation: KVM: Synchronize x86 VM types (2026-06-08 09:20:19 -0700)
>
> ----------------------------------------------------------------
> KVM misc x86 changes for 7.2
>
>  - Handle EXIT_FASTPATH_EXIT_USERSPACE in vendor code to ensure vendor code
>    gets a chance to handle things like reaping the PML buffer.
>
>  - Ensure KVM's copy of CR0 and CR3 are up-to-date on SVM prior to invoking
>    fastpath handlers.
>
>  - Update KVM's view of PV async enabling if and only if the MSR write fully
>    succeeds.
>
>  - Fix a variety of issues where the emulator doesn't honor guest-debug state,
>    and clean up related code along the way.
>
>  - Synthesize EPT Violation and #NPF "error code" bits when injecting faults
>    into L1 that didn't originate in hardware (in which case the VMCS/VMCB
>    doesn't hold relevant information).
>
>  - Add support for virtualizing (well, emulating) AMD's flavor of CPL>0 CPUID
>    faulting.
>
>  - Clean up the GPR APIs so that KVM's use of "raw" is consistent, and fix a
>    variety of minor bugs along the way.
>
>  - Fix an OOB memory access due to not checking the VP ID when handling a
>    Hyper-V PV TLB flush for L2.
>
>  - Fix a bug in the mediated PMU's handling of fixed counters that allowed the
>    guest to bypass the PMU event filter.
>
>  - Allow userspace to return EAGAIN when handling SNP and TDX hypercalls, so
>    the KVM can forward a "retry" status code to the guest, and reserve all
>    unused error codes for future usage.
>
>  - Misc fixes and cleanups.
>
> ----------------------------------------------------------------

Pulled, thanks.

Paolo

> Carlos López (2):
>       KVM: x86: Take PIC lock on KVM_GET_IRQCHIP path
>       Documentation: KVM: Synchronize x86 VM types
>
> Ethan Yang (1):
>       KVM: x86: Don't leave APF half-enabled on bad APF data GPA
>
> Hou Wenlong (7):
>       KVM: x86: Capture "struct x86_exception" in inject_emulated_exception()
>       KVM: x86: Set guest DR6 by kvm_queue_exception_p() in instruction emulation
>       KVM: x86: Honor KVM_GUESTDBG_USE_HW_BP when emulating MOV DR (in emulator)
>       KVM: x86: Honor KVM_GUESTDBG_USE_HW_BP when checking for code breakpoints in emulation
>       KVM: x86: Move KVM_GUESTDBG_SINGLESTEP handling into kvm_inject_emulated_db()
>       KVM: selftests: Verify guest debug DR7.GD checking during instruction emulation
>       KVM: selftests: Verify VMX's GUEST_PENDING_DBG_EXCEPTIONS.BS Consistency Check
>
> Hyunwoo Kim (1):
>       KVM: x86: hyper-v: Bound the bank index when querying sparse banks
>
> Jim Mattson (4):
>       KVM: x86: Prioritize CPUID faulting over CPUID VM-exits in nested VMX
>       KVM: x86: Remove supports_cpuid_fault() helper
>       KVM: x86: Virtualize AMD CPUID faulting
>       KVM: selftests: Update hwcr_msr_test for CPUID faulting bit
>
> Kai Huang (1):
>       KVM: x86: Use <linux/lockdep.h> for lockdep header inclusion
>
> Kevin Cheng (4):
>       KVM: x86: Widen x86_exception's error_code to 64 bits
>       KVM: SVM: Fix nested NPF injection of PFERR_GUEST_{PAGE,FINAL}_MASK bits
>       KVM: VMX: Synthesize nested EPT violation GVA_IS_VALID/GVA_TRANSLATED bits
>       KVM: selftests: Add nested page fault injection test
>
> Krzysztof Kozlowski (1):
>       MAINTAINERS: KVM: Include maintainer profile
>
> Li RongQing (3):
>       KVM: x86: Fix wrong return value type in guest_cpuid_has()
>       KVM: x86: Use fls() instead of ffs() for rmaps histogram bucketing
>       KVM: x86: ioapic: Use old_dest_mode consistently in ioapic_write_indirect()
>
> Sagi Shahar (1):
>       KVM: SEV: Restrict userspace return codes for KVM_HC_MAP_GPA_RANGE
>
> Sean Christopherson (28):
>       KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits
>       KVM: SVM: Refresh vcpu->arch.cr{0,3} prior to invoking fastpath handler
>       KVM: x86: Drop superfluous caching of KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT
>       KVM: x86: Drop superfluous caching of KVM_ASYNC_PF_SEND_ALWAYS
>       KVM: VMX: Refresh GUEST_PENDING_DBG_EXCEPTIONS.BS on all injected #DBs
>       KVM: x86: Drop kvm_vcpu_do_singlestep() now that it's been gutted
>       KVM: selftests: Add all (known) EFLAGS bit definitions
>       KVM: x86: Remove unused X86EMUL_MODE_HOST define
>       KVM: x86: Tell ->inject_page_fault() whether or a fault came from hardware
>       KVM: x86: Consolidate CPUID fault handling for emulator and interception logic
>       KVM: SVM: Truncate INVLPGA address in compatibility mode
>       KVM: x86/xen: Bug the VM if 32-bit KVM observes a 64-bit mode hypercall
>       KVM: x86/xen: Don't truncate RAX when handling hypercall from protected guest
>       KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode
>       KVM: x86: Trace hypercall register *after* truncating values for 32-bit
>       KVM: x86: Rename kvm_cache_regs.h => regs.h
>       KVM: x86: Move inlined GPR, CR, and DR helpers from x86.h to regs.h
>       KVM: x86: Add mode-aware versions of kvm_<reg>_{read,write}() helpers
>       KVM: x86: Drop non-raw kvm_<reg>_write() helpers
>       KVM: nSVM: Use kvm_rax_read() now that it's mode-aware
>       Revert "KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode"
>       KVM: x86: Harden is_64_bit_hypercall() against bugs on 32-bit kernels
>       KVM: x86: Move update_cr8_intercept() to lapic.c
>       KVM: x86: Move async #PF helpers to x86.h (as inlines)
>       KVM: x86: Drop defunct vcpu_tsc_khz() declaration
>       KVM: x86: Remove defunct kvm_load_segment_descriptor() declaration.
>       KVM: x86/pmu: Use hardware value when reprogramming for FIXED_CTR_CTRL changes
>       KVM: selftests: Add regression test for mediated PMU fixed counter filter bug
>
> Vishal Annapurve (2):
>       KVM: x86: Treat KVM's virtual PMU as disabled for TDX VMs
>       KVM: TDX: Allow userspace to return errors to guest for MAPGPA
>
>  Documentation/virt/kvm/api.rst                     |   5 +
>  MAINTAINERS                                        |   1 +
>  arch/x86/include/asm/kvm_host.h                    |  27 +-
>  arch/x86/include/asm/msr-index.h                   |   1 +
>  arch/x86/kvm/cpuid.c                               |  21 +-
>  arch/x86/kvm/cpuid.h                               |  20 +-
>  arch/x86/kvm/debugfs.c                             |   2 +-
>  arch/x86/kvm/emulate.c                             |  22 +-
>  arch/x86/kvm/hyperv.c                              |  26 +-
>  arch/x86/kvm/hyperv.h                              |   4 +-
>  arch/x86/kvm/ioapic.c                              |   2 +-
>  arch/x86/kvm/irq.c                                 |   4 +
>  arch/x86/kvm/kvm_emulate.h                         |  17 +-
>  arch/x86/kvm/lapic.c                               |  28 +-
>  arch/x86/kvm/lapic.h                               |   1 +
>  arch/x86/kvm/mmu.h                                 |   2 +-
>  arch/x86/kvm/mmu/mmu.c                             |   2 +-
>  arch/x86/kvm/mmu/paging_tmpl.h                     |  36 +-
>  arch/x86/kvm/{kvm_cache_regs.h => regs.h}          | 198 +++++++++--
>  arch/x86/kvm/smm.c                                 |   2 +-
>  arch/x86/kvm/svm/nested.c                          |  46 ++-
>  arch/x86/kvm/svm/sev.c                             |  12 +-
>  arch/x86/kvm/svm/svm.c                             |  34 +-
>  arch/x86/kvm/svm/svm.h                             |   2 +-
>  arch/x86/kvm/vmx/nested.c                          |  39 ++-
>  arch/x86/kvm/vmx/nested.h                          |   2 +-
>  arch/x86/kvm/vmx/pmu_intel.c                       |  10 +-
>  arch/x86/kvm/vmx/sgx.c                             |   6 +-
>  arch/x86/kvm/vmx/tdx.c                             |  52 ++-
>  arch/x86/kvm/vmx/vmx.c                             |  40 ++-
>  arch/x86/kvm/vmx/vmx.h                             |   2 +-
>  arch/x86/kvm/x86.c                                 | 374 +++++++++------------
>  arch/x86/kvm/x86.h                                 | 134 ++------
>  arch/x86/kvm/xen.c                                 |  39 ++-
>  tools/testing/selftests/kvm/Makefile.kvm           |   1 +
>  .../testing/selftests/kvm/include/x86/processor.h  |  29 +-
>  tools/testing/selftests/kvm/lib/x86/processor.c    |   2 +-
>  tools/testing/selftests/kvm/lib/x86/vmx.c          |   2 +-
>  tools/testing/selftests/kvm/x86/debug_regs.c       |  88 ++++-
>  tools/testing/selftests/kvm/x86/hwcr_msr_test.c    |   9 +-
>  .../selftests/kvm/x86/nested_tdp_fault_test.c      | 313 +++++++++++++++++
>  .../selftests/kvm/x86/pmu_event_filter_test.c      |   6 +
>  42 files changed, 1116 insertions(+), 547 deletions(-)
>  rename arch/x86/kvm/{kvm_cache_regs.h => regs.h} (59%)
>  create mode 100644 tools/testing/selftests/kvm/x86/nested_tdp_fault_test.c
>