linux

iv/linux

History

Ravi Bangoria b7e4be0a22 KVM: SEV-ES: Delegate LBR virtualization to the processor

As documented in APM[1], LBR Virtualization must be enabled for SEV-ES
guests. Although KVM currently enforces LBRV for SEV-ES guests, there
are multiple issues with it:

o MSR_IA32_DEBUGCTLMSR is still intercepted. Since MSR_IA32_DEBUGCTLMSR
  interception is used to dynamically toggle LBRV for performance reasons,
  this can be fatal for SEV-ES guests. For ex SEV-ES guest on Zen3:

  [guest ~]# wrmsr 0x1d9 0x4
  KVM: entry failed, hardware error 0xffffffff
  EAX=00000004 EBX=00000000 ECX=000001d9 EDX=00000000

  Fix this by never intercepting MSR_IA32_DEBUGCTLMSR for SEV-ES guests.
  No additional save/restore logic is required since MSR_IA32_DEBUGCTLMSR
  is of swap type A.

o KVM will disable LBRV if userspace sets MSR_IA32_DEBUGCTLMSR before the
  VMSA is encrypted. Fix this by moving LBRV enablement code post VMSA
  encryption.

[1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June
     2023, Vol 2, 15.35.2 Enabling SEV-ES.
     https://bugzilla.kernel.org/attachment.cgi?id=304653

Fixes: 376c6d285017 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading")
Co-developed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Message-ID: <20240531044644.768-4-ravi.bangoria@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2024-06-03 13:07:18 -04:00

avic.c

x86: KVM: SVM: add support for Invalid IPI Vector interception

2023-10-12 11:08:59 -04:00

hyperv.c

KVM: nSVM: hyper-v: Enable L2 TLB flush

2022-11-18 12:59:18 -05:00

hyperv.h

KVM: x86: Make Hyper-V emulation optional

2023-12-07 09:34:57 -08:00

nested.c

KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe