| Message ID | 20241009092850.197575-18-nikunj@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add Secure TSC support for SNP guests | expand |
On 10/9/24 04:28, Nikunj A Dadhania wrote: > SecureTSC enabled guests should use TSC as the only clock source, abort > the guest when clock source switches to hypervisor controlled kvmclock. > > Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> > --- > arch/x86/kernel/kvmclock.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c > index 5cd3717e103b..552c28cda874 100644 > --- a/arch/x86/kernel/kvmclock.c > +++ b/arch/x86/kernel/kvmclock.c > @@ -22,6 +22,7 @@ > #include <asm/x86_init.h> > #include <asm/kvmclock.h> > #include <asm/timer.h> > +#include <asm/sev.h> > > static int kvmclock __initdata = 1; > static int kvmclock_vsyscall __initdata = 1; > @@ -155,6 +156,13 @@ static void enable_kvm_sc_work(struct work_struct *work) > { > u8 flags; > > + /* > + * For guest with SecureTSC enabled, TSC should be the only clock source. s/For guest/For a guest/ s/TSC should/The TSC should/ > + * Abort the guest when kvmclock is selected as the clock source. > + */ > + if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) > + snp_abort(); Can a message be issued here? Also, you could use sev_es_terminate() to provide a specific Linux reason code, e.g.: sev_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC_KVMCLOCK); or whatever name you want to use for this situation. Thanks, Tom > + > old_pv_sched_clock = static_call_query(pv_sched_clock); > flags = pvclock_read_flags(&hv_clock_boot[0].pvti); > kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
On 10/11/2024 1:19 AM, Tom Lendacky wrote: > On 10/9/24 04:28, Nikunj A Dadhania wrote: >> SecureTSC enabled guests should use TSC as the only clock source, abort >> the guest when clock source switches to hypervisor controlled kvmclock. >> >> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> >> --- >> arch/x86/kernel/kvmclock.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c >> index 5cd3717e103b..552c28cda874 100644 >> --- a/arch/x86/kernel/kvmclock.c >> +++ b/arch/x86/kernel/kvmclock.c >> @@ -22,6 +22,7 @@ >> #include <asm/x86_init.h> >> #include <asm/kvmclock.h> >> #include <asm/timer.h> >> +#include <asm/sev.h> >> >> static int kvmclock __initdata = 1; >> static int kvmclock_vsyscall __initdata = 1; >> @@ -155,6 +156,13 @@ static void enable_kvm_sc_work(struct work_struct *work) >> { >> u8 flags; >> >> + /* >> + * For guest with SecureTSC enabled, TSC should be the only clock source. > > s/For guest/For a guest/ > s/TSC should/The TSC should/ Ok > >> + * Abort the guest when kvmclock is selected as the clock source. >> + */ >> + if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) >> + snp_abort(); > > Can a message be issued here? > > Also, you could use sev_es_terminate() to provide a specific Linux > reason code, e.g.: > > sev_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC_KVMCLOCK); > > or whatever name you want to use for this situation. Sure, will add. Regards Nikunj
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 5cd3717e103b..552c28cda874 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -22,6 +22,7 @@ #include <asm/x86_init.h> #include <asm/kvmclock.h> #include <asm/timer.h> +#include <asm/sev.h> static int kvmclock __initdata = 1; static int kvmclock_vsyscall __initdata = 1; @@ -155,6 +156,13 @@ static void enable_kvm_sc_work(struct work_struct *work) { u8 flags; + /* + * For guest with SecureTSC enabled, TSC should be the only clock source. + * Abort the guest when kvmclock is selected as the clock source. + */ + if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) + snp_abort(); + old_pv_sched_clock = static_call_query(pv_sched_clock); flags = pvclock_read_flags(&hv_clock_boot[0].pvti); kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
SecureTSC enabled guests should use TSC as the only clock source, abort the guest when clock source switches to hypervisor controlled kvmclock. Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> --- arch/x86/kernel/kvmclock.c | 8 ++++++++ 1 file changed, 8 insertions(+)