diff options
| author | Ravi Bangoria <[email protected]> | 2024-05-31 04:46:44 +0000 |
|---|---|---|
| committer | Paolo Bonzini <[email protected]> | 2024-06-03 13:07:18 -0400 |
| commit | b7e4be0a224fe5c6be30c1c8bdda8d2317ad6ba4 (patch) | |
| tree | 5f97963333ec76d6a6e233b0fc667749f73ff872 /tools/perf/util/trace-event-scripting.c | |
| parent | d922056215617eedfbdbc29fe49953423686fe5e (diff) | |
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 <[email protected]>
Signed-off-by: Nikunj A Dadhania <[email protected]>
Signed-off-by: Ravi Bangoria <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Diffstat (limited to 'tools/perf/util/trace-event-scripting.c')
0 files changed, 0 insertions, 0 deletions