linux/virt
Paolo Bonzini a104e0a305 KVM SVM changes for 6.18
- 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 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.
 
  - Mitigate the potential for TOCTOU bugs when accessing GHCB fields by
    wrapping all accesses via READ_ONCE().
 
  - Validate the XCR0 provided by the guest (via the GHCB) to avoid tracking a
    bogous XCR0 value in KVM's software model.
 
  - 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 do the "heavy" lifting.
 
  - 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 could clobber a different vCPU's
    TSC_AUX due to hardware not matching the value cached in the user-return MSR
    infrastructure.
 
  - Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is supported,
    and clean up the AVIC initialization code along the way.
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Merge tag 'kvm-x86-svm-6.18' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.18

 - 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 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.

 - Mitigate the potential for TOCTOU bugs when accessing GHCB fields by
   wrapping all accesses via READ_ONCE().

 - Validate the XCR0 provided by the guest (via the GHCB) to avoid tracking a
   bogous XCR0 value in KVM's software model.

 - 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 do the "heavy" lifting.

 - 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 could clobber a different vCPU's
   TSC_AUX due to hardware not matching the value cached in the user-return MSR
   infrastructure.

 - Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is supported,
   and clean up the AVIC initialization code along the way.
History 2025-09-30 13:34:12 -04:00
..
kvm KVM SVM changes for 6.18 2025-09-30 13:34:12 -04:00
lib irqbypass: Require producers to pass in Linux IRQ number during registration 2025-06-20 13:52:41 -07:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00