Haitao Shan
2011-Sep-16 00:46 UTC
[Xen-devel] [PATCH] Fix PV CPUID virtualization of XSave
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@intel.com>
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++ )
+ {
+ 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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Jan Beulich
2011-Sep-16 07:13 UTC
Re: [Xen-devel] [PATCH] Fix PV CPUID virtualization of XSave
>>> On 16.09.11 at 02:46, Haitao Shan <maillists.shan@gmail.com> 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@intel.com> > > 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; > }_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Haitao Shan
2011-Sep-18 09:49 UTC
Re: [Xen-devel] [PATCH] Fix PV CPUID virtualization of XSave
2011/9/16 Jan Beulich <JBeulich@suse.com>:>>>> On 16.09.11 at 02:46, Haitao Shan <maillists.shan@gmail.com> 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@intel.com> >> >> 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)? > > JanNice 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; >> } > > > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Haitao Shan
2011-Sep-19 13:37 UTC
Re: [Xen-devel] [PATCH] Fix PV CPUID virtualization of XSave
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@intel.com>
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@gmail.com>:> 2011/9/16 Jan Beulich <JBeulich@suse.com>:
>>>>> On 16.09.11 at 02:46, Haitao Shan
<maillists.shan@gmail.com> 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@intel.com>
>>>
>>> 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;
>>> }
>>
>>
>>
>>
>
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