[2/3] KVM: x86: Propagate AMD's IbrsSameMode to the guest

Commit Message

Yosry Ahmed Feb. 21, 2025, 4:33 p.m. UTC

If IBRS provides same mode (kernel/user or host/guest) protection on the
host, then by definition it also provides same mode protection in the
guest. In fact, all different modes from the guest's perspective are the
same mode from the host's perspective anyway.

Propagate IbrsSameMode to the guests.

Signed-off-by: Yosry Ahmed <[e-mail]>
---
 arch/x86/kvm/cpuid.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index edef30359c198..05d7bbfbb8885 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1103,6 +1103,7 @@  void kvm_set_cpu_caps(void)
 		F(AMD_SSB_NO),
 		F(AMD_STIBP),
 		F(AMD_STIBP_ALWAYS_ON),
+		F(AMD_IBRS_SAME_MODE),
 		F(AMD_PSFD),
 		F(AMD_IBPB_RET),
 	);