[GIT PULL] KVM: x86: SVM changes for 7.1 (short version)

[Sean Christopherson]

This is (obviously) the partial version of the SVM changes.

The highlight is here is the AVIC IRQ window fixes and optimizations.  The OSVW
changes aren't motivated by anything beyond a "someone is wrong on the internet!"
type reaction.

The following changes since commit 11439c4635edd669ae435eec308f4ab8a0804808:

  Linux 7.0-rc2 (2026-03-01 15:39:31 -0800)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-svm-partial-7.1

for you to fetch changes up to a56444d5e7387effbc61d6b98fe5d68897017fc9:

  KVM: SVM: Skip OSVW MSR reads if current CPU doesn't support the feature (2026-03-03 12:23:26 -0800)

----------------------------------------------------------------
KVM SVM changes for 7.1 (short version)

 - Fix and optimize IRQ window inhibit handling for AVIC (the tracking needs to
   be per-vCPU, e.g. so that KVM doesn't prematurely re-enable AVIC if multiple
   vCPUs have to-be-injected IRQs).

 - Fix an undefined behavior warning where a crafty userspace can read the
   "avic" module param before it's fully initialized.

 - Fix a (likely benign) bug in the "OS-visible workarounds" handling, where
   KVM could clobber state when enabling virtualization on multiple CPUs in
   parallel, and clean up and optimize the code.

----------------------------------------------------------------
Gal Pressman (1):
      KVM: SVM: Fix UBSAN warning when reading avic parameter

Li RongQing (1):
      KVM: SVM: Mark module parameters as __ro_after_init for security and performance

Sean Christopherson (9):
      KVM: SVM: Fix clearing IRQ window inhibit with nested guests
      KVM: SVM: Fix IRQ window inhibit handling across multiple vCPUs
      KVM: SVM: Optimize IRQ window inhibit handling
      KVM: Isolate apicv_update_lock and apicv_nr_irq_window_req in a cacheline
      KVM: SVM: Serialize updates to global OS-Visible Workarounds variables
      KVM: SVM: Skip OSVW MSR reads if KVM is treating all errata as present
      KVM: SVM: Extract OS-visible workarounds setup to helper function
      KVM: SVM: Skip OSVW variable updates if current CPU's errata are a subset
      KVM: SVM: Skip OSVW MSR reads if current CPU doesn't support the feature

 arch/x86/include/asm/kvm_host.h |  29 ++++++-
 arch/x86/kvm/svm/avic.c         |  17 ++++-
 arch/x86/kvm/svm/sev.c          |   8 +-
 arch/x86/kvm/svm/svm.c          | 164 ++++++++++++++++++++++++----------------
 arch/x86/kvm/svm/svm.h          |   1 +
 arch/x86/kvm/x86.c              |  45 ++++++++++-
 6 files changed, 188 insertions(+), 76 deletions(-)