On 7/31/24 10:08, 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> > Tested-by: Peter Gonda <pgonda@xxxxxxxxxx> Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx> > --- > arch/x86/coco/sev/shared.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arch/x86/coco/sev/shared.c b/arch/x86/coco/sev/shared.c > index 71de53194089..c2a9e2ada659 100644 > --- a/arch/x86/coco/sev/shared.c > +++ b/arch/x86/coco/sev/shared.c > @@ -1140,6 +1140,16 @@ 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. > + * This file is included from kernel/sev.c and boot/compressed/sev.c, > + * use sev_status here as cc_platform_has() is not available when > + * compiling boot/compressed/sev.c. > + */ > + if (sev_status & MSR_AMD64_SNP_SECURE_TSC) > + return ES_VMM_ERROR; > + > ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0); > if (ret != ES_OK) > return ret;
