On 24/01/2024 3:27 pm, Jan Beulich wrote:
> ... if available only, of course.
>
> Signed-off-by: Jan Beulich <[email protected]>
>
> --- a/xen/arch/x86/cpu/common.c
> +++ b/xen/arch/x86/cpu/common.c
> @@ -406,9 +406,15 @@ void __init early_cpu_init(bool verbose)
> paddr_bits -= (ebx >> 6) & 0x3f;
> }
>
> - if (!(c->x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)))
> + if (!(c->x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON))) {
> + uint64_t smi_count;
> +
> park_offline_cpus = opt_mce;
>
> + if (!verbose && !rdmsr_safe(MSR_SMI_COUNT, smi_count))
> + setup_force_cpu_cap(X86_FEATURE_SMI_COUNT);
> + }
> +
I know you're re-using an existing condition, but I think it's more
likely that it's Intel-only than common to VIA and Shanghai.
Also, why is gated on verbose?
(I think I can see why this is rhetorical question, and I expect you can
guess what the feedback will be.)
> initialize_cpu_data(0);
> }
>
> --- a/xen/arch/x86/include/asm/cpufeatures.h
> +++ b/xen/arch/x86/include/asm/cpufeatures.h
> @@ -24,7 +24,7 @@ XEN_CPUFEATURE(APERFMPERF, X86_SY
> XEN_CPUFEATURE(MFENCE_RDTSC, X86_SYNTH( 9)) /* MFENCE synchronizes
> RDTSC */
> XEN_CPUFEATURE(XEN_SMEP, X86_SYNTH(10)) /* SMEP gets used by Xen
> itself */
> XEN_CPUFEATURE(XEN_SMAP, X86_SYNTH(11)) /* SMAP gets used by Xen
> itself */
> -/* Bit 12 unused. */
> +XEN_CPUFEATURE(SMI_COUNT, X86_SYNTH(12)) /* MSR_SMI_COUNT exists */
> XEN_CPUFEATURE(IND_THUNK_LFENCE, X86_SYNTH(13)) /* Use IND_THUNK_LFENCE */
> XEN_CPUFEATURE(IND_THUNK_JMP, X86_SYNTH(14)) /* Use IND_THUNK_JMP */
> XEN_CPUFEATURE(SC_NO_BRANCH_HARDEN, X86_SYNTH(15)) /* (Disable) Conditional
> branch hardening */
> --- a/xen/arch/x86/include/asm/msr-index.h
> +++ b/xen/arch/x86/include/asm/msr-index.h
> @@ -28,6 +28,8 @@
> #define TEST_CTRL_SPLITLOCK_DETECT (_AC(1, ULL) << 29)
> #define TEST_CTRL_SPLITLOCK_DISABLE (_AC(1, ULL) << 31)
>
> +#define MSR_SMI_COUNT 0x00000034
> +
> #define MSR_INTEL_CORE_THREAD_COUNT 0x00000035
> #define MSR_CTC_THREAD_MASK 0x0000ffff
> #define MSR_CTC_CORE_MASK _AC(0xffff0000, U)
> --- a/xen/arch/x86/nmi.c
> +++ b/xen/arch/x86/nmi.c
> @@ -589,9 +589,20 @@ static void cf_check do_nmi_stats(unsign
> unsigned int cpu;
> bool pend, mask;
>
> - printk("CPU\tNMI\n");
> + printk("CPU\tNMI%s\n", boot_cpu_has(X86_FEATURE_SMI_COUNT) ? "\tSMI" :
> "");
> for_each_online_cpu ( cpu )
> - printk("%3u\t%3u\n", cpu, per_cpu(nmi_count, cpu));
> + {
> + printk("%3u\t%3u", cpu, per_cpu(nmi_count, cpu));
> + if ( boot_cpu_has(X86_FEATURE_SMI_COUNT) )
> + {
> + unsigned int smi_count, dummy;
> +
> + rdmsr(MSR_SMI_COUNT, smi_count, dummy);
> + printk("\t%3u\n", smi_count);
This reads MSR_SMI_COUNT repeatedly on the same CPU.
You'll need to IPI all CPUs to dump the count into a per-cpu variable.
~Andrew
