On 10/30/23 01:36, Nikunj A Dadhania wrote:
The hypervisor should not be intercepting RDTSC/RDTSCP when Secure TSC
is enabled. A #VC exception will be generated if the RDTSC/RDTSCP
instructions are being intercepted. If this should occur and Secure
TSC is enabled, terminate guest execution.
Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
---
arch/x86/kernel/sev-shared.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index ccb0915e84e1..833b0ae38f0b 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -991,6 +991,13 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
bool rdtscp = (exit_code == SVM_EXIT_RDTSCP);
enum es_result ret;
+ /*
+ * RDTSC and RDTSCP should not be intercepted when Secure TSC is
+ * enabled. Terminate the SNP guest when the interception is enabled.
+ */
+ if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
If you have to use sev_status, then please document why cc_platform_has()
can't be used in the comment above.
Thanks,
Tom
+ return ES_VMM_ERROR;
+
ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0);
if (ret != ES_OK)
return ret;
