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@xxxxxxx>
> ---
> 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);
