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[PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable

Zhao Liu posted 20 patches 3 months, 2 weeks ago
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Zhao Liu <zhao1.liu@intel.com>, Marcelo Tosatti <mtosatti@redhat.com>
There is a newer version of this series
[PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
Posted by Zhao Liu 3 months, 2 weeks ago 
Cet-u and cet-s are supervisor xstates. Their states are saved/loaded by
saving/loading related CET MSRs. And there's a vmsd "vmstate_cet" to
migrate these MSRs.

Thus, it's safe to mark them as migratable.

Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 target/i386/cpu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 0bb65e8c5321..c08066a338a3 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1522,7 +1522,8 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK |
             XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK |
             XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK |
-            XSTATE_PKRU_MASK | XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
+            XSTATE_PKRU_MASK | XSTATE_CET_U_MASK | XSTATE_CET_S_MASK |
+            XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
             XSTATE_XTILE_DATA_MASK,
     },
     [FEAT_XSAVE_XCR0_HI] = {
-- 
2.34.1
Re: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
Posted by Chao Gao 3 months, 1 week ago 
On Fri, Oct 24, 2025 at 02:56:28PM +0800, Zhao Liu wrote:
>Cet-u and cet-s are supervisor xstates. Their states are saved/loaded by
>saving/loading related CET MSRs. And there's a vmsd "vmstate_cet" to
>migrate these MSRs.
>
>Thus, it's safe to mark them as migratable.
>
>Tested-by: Farrah Chen <farrah.chen@intel.com>
>Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
>---
> target/i386/cpu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>index 0bb65e8c5321..c08066a338a3 100644
>--- a/target/i386/cpu.c
>+++ b/target/i386/cpu.c
>@@ -1522,7 +1522,8 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>         .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK |
>             XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK |
>             XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK |
>-            XSTATE_PKRU_MASK | XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
>+            XSTATE_PKRU_MASK | XSTATE_CET_U_MASK | XSTATE_CET_S_MASK |
>+            XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
>             XSTATE_XTILE_DATA_MASK,

Supervisor states are enumerated via CPUID[EAX=0xd,ECX=1].ECX/EDX while user
states are enumerated via CPUID[EAX=0xd,ECX=0].EAX/EDX. So, maybe we need to 
two new feature words?

>     },
>     [FEAT_XSAVE_XCR0_HI] = {
>-- 
>2.34.1
>
Re: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
Posted by Zhao Liu 3 months, 1 week ago 
On Wed, Oct 29, 2025 at 02:10:08PM +0800, Chao Gao wrote:
> Date: Wed, 29 Oct 2025 14:10:08 +0800
> From: Chao Gao <chao.gao@intel.com>
> Subject: Re: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as
>  migratable
> 
> On Fri, Oct 24, 2025 at 02:56:28PM +0800, Zhao Liu wrote:
> >Cet-u and cet-s are supervisor xstates. Their states are saved/loaded by
> >saving/loading related CET MSRs. And there's a vmsd "vmstate_cet" to
> >migrate these MSRs.
> >
> >Thus, it's safe to mark them as migratable.
> >
> >Tested-by: Farrah Chen <farrah.chen@intel.com>
> >Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> >---
> > target/i386/cpu.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> >diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> >index 0bb65e8c5321..c08066a338a3 100644
> >--- a/target/i386/cpu.c
> >+++ b/target/i386/cpu.c
> >@@ -1522,7 +1522,8 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> >         .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK |
> >             XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK |
> >             XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK |
> >-            XSTATE_PKRU_MASK | XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
> >+            XSTATE_PKRU_MASK | XSTATE_CET_U_MASK | XSTATE_CET_S_MASK |
> >+            XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
> >             XSTATE_XTILE_DATA_MASK,
> 
> Supervisor states are enumerated via CPUID[EAX=0xd,ECX=1].ECX/EDX while user
> states are enumerated via CPUID[EAX=0xd,ECX=0].EAX/EDX. So, maybe we need to 
> two new feature words?

Yes, I added the mask into wrong place...

Regards,
Zhao
Re: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
Posted by Zhao Liu 3 months, 2 weeks ago 
On Fri, Oct 24, 2025 at 02:56:28PM +0800, Zhao Liu wrote:
> Date: Fri, 24 Oct 2025 14:56:28 +0800
> From: Zhao Liu <zhao1.liu@intel.com>
> Subject: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
> X-Mailer: git-send-email 2.34.1
> 
> Cet-u and cet-s are supervisor xstates. Their states are saved/loaded by
> saving/loading related CET MSRs. And there's a vmsd "vmstate_cet" to
> migrate these MSRs.
> 
> Thus, it's safe to mark them as migratable.
> 
> Tested-by: Farrah Chen <farrah.chen@intel.com>
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>  target/i386/cpu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 0bb65e8c5321..c08066a338a3 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1522,7 +1522,8 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>          .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK |
>              XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK |
>              XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK |
> -            XSTATE_PKRU_MASK | XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
> +            XSTATE_PKRU_MASK | XSTATE_CET_U_MASK | XSTATE_CET_S_MASK |

CET-U & CET-S should be added to FEAT_XSAVE_XSS_LO.

> +            XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
>              XSTATE_XTILE_DATA_MASK,
>      },
>      [FEAT_XSAVE_XCR0_HI] = {
> -- 
> 2.34.1
>
Re: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
Posted by Chao Gao 3 months, 1 week ago 
On Mon, Oct 27, 2025 at 07:34:56PM +0800, Zhao Liu wrote:
>On Fri, Oct 24, 2025 at 02:56:28PM +0800, Zhao Liu wrote:
>> Date: Fri, 24 Oct 2025 14:56:28 +0800
>> From: Zhao Liu <zhao1.liu@intel.com>
>> Subject: [PATCH v3 16/20] i386/cpu: Mark cet-u & cet-s xstates as migratable
>> X-Mailer: git-send-email 2.34.1
>> 
>> Cet-u and cet-s are supervisor xstates. Their states are saved/loaded by
>> saving/loading related CET MSRs. And there's a vmsd "vmstate_cet" to
>> migrate these MSRs.
>> 
>> Thus, it's safe to mark them as migratable.
>> 
>> Tested-by: Farrah Chen <farrah.chen@intel.com>
>> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
>> ---
>>  target/i386/cpu.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index 0bb65e8c5321..c08066a338a3 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -1522,7 +1522,8 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>>          .migratable_flags = XSTATE_FP_MASK | XSTATE_SSE_MASK |
>>              XSTATE_YMM_MASK | XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK |
>>              XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | XSTATE_Hi16_ZMM_MASK |
>> -            XSTATE_PKRU_MASK | XSTATE_ARCH_LBR_MASK | XSTATE_XTILE_CFG_MASK |
>> +            XSTATE_PKRU_MASK | XSTATE_CET_U_MASK | XSTATE_CET_S_MASK |
>
>CET-U & CET-S should be added to FEAT_XSAVE_XSS_LO.

Yes. XSTATE_ARCH_LBR_MASK as well.

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