[PATCH] kvm: fix wrong exception emulation in check_rdtsc

From: Hou Wenlong
Date: Tue Aug 17 2021 - 23:36:41 EST


According to Intel's SDM Vol2 and AMD's APM Vol3, when
CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
level 0 should trigger a #GP.

Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
Signed-off-by: Hou Wenlong <houwenlong93@xxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2837110e66ed..c589ac832265 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4206,7 +4206,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
u64 cr4 = ctxt->ops->get_cr(ctxt, 4);

if (cr4 & X86_CR4_TSD && ctxt->ops->cpl(ctxt))
- return emulate_ud(ctxt);
+ return emulate_gp(ctxt, 0);

return X86EMUL_CONTINUE;
}
--
2.31.1