On Tue, Nov 28, 2023 at 5:02 AM Nikunj A Dadhania <nikunj@xxxxxxx> 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 | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c > index ccb0915e84e1..6d9ef5897421 100644 > --- a/arch/x86/kernel/sev-shared.c > +++ b/arch/x86/kernel/sev-shared.c > @@ -991,6 +991,16 @@ 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; Is this not a cc_platform_has situation? I don't recall how the conversation shook out for TDX's forcing X86_FEATURE_TSC_RELIABLE versus having a cc_attr_secure_tsc > + > ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0); > if (ret != ES_OK) > return ret; > -- > 2.34.1 > -- -Dionna Glaze, PhD (she/her)
