TL;DR: KVM's AVIC and optimized APIC map code doesn't correctly handle
various edge cases that are architecturally legal(ish), but are unlikely
to occur in most real world scenarios.
I have tested this heavily with KUT, but I haven't booted Windows and
don't have access to x2AVIC, so additional testing would be much
appreciated.
v3:
- Collect reviews. [Paolo]
- Drop "partial" x2APIC inhibit and instead delete the memslot.
[Maxim, Suravee]
- Skip logical mode updates for x2APIC, which just reuses the
phys_map with some clever logic. [Suravee]
- Add a fix for "nodecode write" traps. [Alejandro]
v2:
- https://lore.kernel.org/all/20220903002254.2411750-1-seanjc@xxxxxxxxxx
- Collect reviews. [Li, Maxim]
- Disable only MMIO access when x2APIC is enabled (instead of disabling
all of AVIC). [Maxim]
- Inhibit AVIC when logical IDs are aliased. [Maxim]
- Tweak name of set_virtual_apic_mode() hook. [Maxim]
- Straight up revert logical ID fastpath mess. [Maxim]
- Reword changelog about skipping vCPU during logical setup. [Maxim]
- Fix LDR updates on AVIC. [Maxim?]
- Fix a nasty ISR caching bug.
- Flush TLB when activating AVIC.
v1: https://lore.kernel.org/all/20220831003506.4117148-1-seanjc@xxxxxxxxxx
Sean Christopherson (27):
KVM: x86: Blindly get current x2APIC reg value on "nodecode write"
traps
KVM: x86: Purge "highest ISR" cache when updating APICv state
KVM: SVM: Flush the "current" TLB when activating AVIC
KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid
target
KVM: x86: Don't inhibit APICv/AVIC if xAPIC ID mismatch is due to
32-bit ID
KVM: x86: Move APIC access page helper to common x86 code
KVM: x86: Inhibit APIC memslot if x2APIC and AVIC are enabled
KVM: SVM: Don't put/load AVIC when setting virtual APIC mode
KVM: SVM: Replace "avic_mode" enum with "x2avic_enabled" boolean
KVM: SVM: Compute dest based on sender's x2APIC status for AVIC kick
Revert "KVM: SVM: Use target APIC ID to complete x2AVIC IRQs when
possible"
KVM: SVM: Document that vCPU ID == APIC ID in AVIC kick fastpatch
KVM: SVM: Add helper to perform final AVIC "kick" of single vCPU
KVM: x86: Explicitly skip optimized logical map setup if vCPU's LDR==0
KVM: x86: Explicitly track all possibilities for APIC map's logical
modes
KVM: x86: Skip redundant x2APIC logical mode optimized cluster setup
KVM: x86: Disable APIC logical map if logical ID covers multiple MDAs
KVM: x86: Disable APIC logical map if vCPUs are aliased in logical
mode
KVM: x86: Honor architectural behavior for aliased 8-bit APIC IDs
KVM: x86: Inhibit APICv/AVIC if the optimized physical map is disabled
KVM: SVM: Inhibit AVIC if vCPUs are aliased in logical mode
KVM: SVM: Always update local APIC on writes to logical dest register
KVM: SVM: Update svm->ldr_reg cache even if LDR is "bad"
KVM: SVM: Require logical ID to be power-of-2 for AVIC entry
KVM: SVM: Handle multiple logical targets in AVIC kick fastpath
KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps
Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on
a running vcpu"
Suravee Suthikulpanit (1):
KVM: SVM: Fix x2APIC Logical ID calculation for
avic_kick_target_vcpus_fast
Documentation/virt/kvm/x86/errata.rst | 11 +
arch/x86/include/asm/kvm_host.h | 51 +++-
arch/x86/kvm/lapic.c | 224 +++++++++++++---
arch/x86/kvm/lapic.h | 2 +
arch/x86/kvm/svm/avic.c | 363 ++++++++++++--------------
arch/x86/kvm/svm/svm.c | 4 +-
arch/x86/kvm/svm/svm.h | 11 +-
arch/x86/kvm/vmx/vmx.c | 36 +--
arch/x86/kvm/x86.c | 7 +
9 files changed, 426 insertions(+), 283 deletions(-)
base-commit: 372d07084593dc7a399bf9bee815711b1fb1bcf2
--
2.37.3.968.ga6b4b080e4-goog
