>>> On 16.09.11 at 02:46, Haitao Shan <maillists.shan@xxxxxxxxx> wrote:
> Hi, Keir,
>
> The patch will fix XSave CPUID virtualization for PV guests. The XSave
> area size returned by CPUID leaf D is changed dynamically depending on
> the XCR0. Tools/libxc only assigns a static value. The fix will adjust
> xsave area size during runtime.
>
> Note: This fix is already in HVM cpuid virtualization. And Dom0 is not
> affected, either.
>
> Signed-off-by: Shan Haitao <haitao.shan@xxxxxxxxx>
>
> Shan Haitao
>
> diff -r 5fe770c8a8a3 xen/arch/x86/traps.c
> --- a/xen/arch/x86/traps.c Tue Sep 06 15:49:40 2011 +0100
> +++ b/xen/arch/x86/traps.c Wed Sep 07 02:09:12 2011 +0800
> @@ -770,6 +770,30 @@ static void pv_cpuid(struct cpu_user_reg
> {
> if ( !cpuid_hypervisor_leaves(a, c, &a, &b, &c, &d) )
> domain_cpuid(current->domain, a, c, &a, &b, &c, &d);
> +
> + switch ( a )
> + {
> + case 0xd:
> + {
> + unsigned int sub_leaf, _eax, _ebx, _ecx, _edx;
> + /* EBX value of main leaf 0 depends on enabled xsave features
> */
> + if ( c == 0 && current->arch.xcr0 )
> + {
> + /* reset EBX to default value first */
> + b = XSTATE_AREA_MIN_SIZE;
> + for ( sub_leaf = 2; sub_leaf < 64; sub_leaf++ )
Shouldn't the upper bound be 63 here (as bit 63 serves a different
purpose, and if that bit was set code changes would be required in
various other places)?
Jan
> + {
> + if ( !(current->arch.xcr0 & (1ULL << sub_leaf)) )
> + continue;
> + domain_cpuid(current->domain, a, c, &_eax, &_ebx, &_ecx,
> + &_edx);
> + if ( (_eax + _ebx) > b )
> + b = _eax + _ebx;
> + }
> + }
> + break;
> + }
> + }
> goto out;
> }
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