On Wed, Nov 01, 2017 at 04:16:08PM -0500, Brijesh Singh wrote:
> A SEV-enabled guest must use ASIDs from the defined subset, while non-SEV
> guests can use the remaining ASID range. The range of allowed SEV guest
> ASIDs is [1 - CPUID_8000_001F[ECX][31:0]].
> 
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: Paolo Bonzini <[email protected]>
> Cc: "Radim Krčmář" <[email protected]>
> Cc: Joerg Roedel <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: Tom Lendacky <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Improvements-by: Borislav Petkov <[email protected]>
> Signed-off-by: Brijesh Singh <[email protected]>
> Reviewed-by: Borislav Petkov <[email protected]>
> ---
>  arch/x86/kvm/svm.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index be2e98c01b22..d4b62536e305 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -323,6 +323,8 @@ enum {
>  
>  #define VMCB_AVIC_APIC_BAR_MASK              0xFFFFFFFFFF000ULL
>  
> +static unsigned int max_sev_asid;
> +
>  static inline void mark_all_dirty(struct vmcb *vmcb)
>  {
>       vmcb->control.clean = 0;
> @@ -787,7 +789,7 @@ static int svm_hardware_enable(void)
>       sd->asid_generation = 1;
>       sd->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1;
>       sd->next_asid = sd->max_asid + 1;
> -     sd->min_asid = 1;
> +     sd->min_asid = max_sev_asid + 1;
>  
>       gdt = get_current_gdt_rw();
>       sd->tss_desc = (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS);
> @@ -1054,6 +1056,15 @@ static int avic_ga_log_notifier(u32 ga_tag)
>       return 0;
>  }
>  
> +/*
> + * Get the maximum number of encrypted guests:
> + *  Fn8001_001F[ECX][31:0]: Number of supported guests.
> + */
> +static __init void sev_hardware_setup(void)
> +{
> +     max_sev_asid = cpuid_ecx(0x8000001F);
> +}
> +
>  static __init int svm_hardware_setup(void)
>  {
>       int cpu;
> @@ -1084,6 +1095,16 @@ static __init int svm_hardware_setup(void)
>               kvm_tsc_scaling_ratio_frac_bits = 32;
>       }
>  
> +     if (sev) {
> +             if (boot_cpu_has(X86_FEATURE_SEV) &&
> +                 IS_ENABLED(CONFIG_KVM_AMD_SEV)) {
> +                     sev_hardware_setup();
> +                     pr_info("SEV supported\n");
> +             } else {
> +                     sev = false;
> +             }
> +     }

Btw, upon a second look, this hunk should go with the previous patch.
This patch deals with ASID ranges, as the commit message states.

-- 
Regards/Gruss,
    Boris.

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