On Thu, May 12, 2011 at 09:23:45AM -0400, Avi Kivity wrote:
> Instead of blacklisting known-unsupported cpuid leaves, whitelist known-
> supported leaves. This is more conservative and prevents us from reporting
> features we don't support. Also whitelist a few more leaves while at it.
Good improvement, some small annotations inline.
>
> Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
> ---
>
> Joerg, if you can review the AMD bits... I was somewhat dazed and confused
> when I got there (but tried to continue).
>
> arch/x86/kvm/x86.c | 37 +++++++++++++++++++++++++++++++++++--
> 1 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 77c9d867..78149d3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2283,6 +2283,13 @@ static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> entry->flags = 0;
> }
>
> +static bool supported_xcr0_bit(unsigned bit)
> +{
> + u64 mask = ((u64)1 << bit);
> +
> + return mask & (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) & host_xcr0;
> +}
> +
> #define F(x) bit(X86_FEATURE_##x)
>
> static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> @@ -2393,6 +2400,8 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> }
> break;
> }
> + case 9:
> + break;
> case 0xb: {
> int i, level_type;
>
> @@ -2414,7 +2423,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
>
> entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> for (i = 1; *nent < maxnent && i < 64; ++i) {
> - if (entry[i].eax == 0)
> + if (entry[i].eax == 0 || !supported_xcr0_bit(i))
> continue;
> do_cpuid_1_ent(&entry[i], function, i);
> entry[i].flags |=
> @@ -2451,6 +2460,24 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> entry->ecx &= kvm_supported_word6_x86_features;
> cpuid_mask(&entry->ecx, 6);
> break;
> + case 0x80000008: {
> + u8 g_phys_as = entry->eax >> 16;
> + u8 virt_as = max(entry->eax >> 8, 48U);
Shouldn't that be 'max((entry->eax >> 8) & 0xff, 48U)'? Seems safer when
the entry->eax contains a non-zero g_phys value.
> + u8 phys_as = entry->eax;
> +
> + if (!g_phys_as)
> + g_phys_as = phys_as;
> + entry->eax = g_phys_as | (virt_as << 8);
It is optional, but since we support nesting we can also encode
g_phys_as in bits 23:16.
> + entry->ebx = entry->edx = 0;
> + break;
> + }
> + case 0x80000019:
> + entry->ecx = entry->edx = 0;
> + break;
> + case 0x8000001a:
> + break;
> + case 0x8000001d:
> + break;
> /*Add support for Centaur's CPUID instruction*/
> case 0xC0000000:
> /*Just support up to 0xC0000004 now*/
> @@ -2460,10 +2487,16 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> entry->edx &= kvm_supported_word5_x86_features;
> cpuid_mask(&entry->edx, 5);
> break;
> + case 3: /* Processor serial number */
> + case 5: /* MONITOR/MWAIT */
> + case 6: /* Thermal management */
> + case 0xA: /* Architectural Performance Monitoring */
> + case 0x80000007: /* Advanced power management */
> case 0xC0000002:
> case 0xC0000003:
> case 0xC0000004:
> - /*Now nothing to do, reserved for the future*/
> + default:
> + entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
> break;
> }
>
> --
> 1.7.4.3
>
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