Jan, Keir,
Updated patch is attached.
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>
diff -r e90438f6e6d1 xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c Wed Sep 14 11:38:13 2011 +0100
+++ b/xen/arch/x86/hvm/hvm.c Mon Sep 19 14:34:15 2011 +0800
@@ -2426,7 +2426,7 @@ void hvm_cpuid(unsigned int input, unsig
{
/* reset EBX to default value first */
*ebx = XSTATE_AREA_MIN_SIZE;
- for ( sub_leaf = 2; sub_leaf < 64; sub_leaf++ )
+ for ( sub_leaf = 2; sub_leaf < 63; sub_leaf++ )
{
if ( !(v->arch.xcr0 & (1ULL << sub_leaf)) )
continue;
diff -r e90438f6e6d1 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c Wed Sep 14 11:38:13 2011 +0100
+++ b/xen/arch/x86/traps.c Mon Sep 19 14:34:15 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 < 63; sub_leaf++ )
+ {
+ 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;
}
2011/9/18 Haitao Shan <maillists.shan@xxxxxxxxx>:
> 2011/9/16 Jan Beulich <JBeulich@xxxxxxxx>:
>>>>> 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
> Nice catch! I will update the patch. The same piece of code is
> borrowed from hvm_cpuid(), where I can change the value from 64 to 63,
> too.
>
> Shan Haitao
>
>>
>>> + {
>>> + 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;
>>> }
>>
>>
>>
>>
>
pv_xsave_cpuid_fix.patch
Description: Binary data
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