x86/sev: Ensure SVSM reserved fields are initialized to zero

[PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

Posted by Tom Lendacky 1 month, 3 weeks ago

In order to support future versions of the SVSM_CORE_PVALIDATE call,
all reserved fields within a PVALIDATE entry must be set to zero as an
SVSM should be ensuring all reserved fields are zero in order to support
future usage of reserved areas based on the protocol version.

Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/boot/startup/sev-shared.c | 1 +
 arch/x86/coco/sev/core.c           | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
index ac7dfd21ddd4..a34cd19796f9 100644
--- a/arch/x86/boot/startup/sev-shared.c
+++ b/arch/x86/boot/startup/sev-shared.c
@@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
 	pc->entry[0].page_size = RMP_PG_SIZE_4K;
 	pc->entry[0].action    = validate;
 	pc->entry[0].ignore_cf = 0;
+	pc->entry[0].rsvd      = 0;
 	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
 
 	/* Protocol 0, Call ID 1 */
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 400a6ab75d45..14ef5908fb27 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
 		pe->page_size = RMP_PG_SIZE_4K;
 		pe->action    = action;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = pfn;
 
 		pe++;
@@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
 		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
 		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = e->gfn;
 
 		pe++;

base-commit: 4c699535a3d483562354432a945a035f15dfceeb
-- 
2.46.2

Re: [sos-linux-ext-patches] [PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

Posted by Nikunj A. Dadhania 1 month, 2 weeks ago


On 8/13/2025 8:56 PM, Tom Lendacky wrote:

> In order to support future versions of the SVSM_CORE_PVALIDATE call,
> all reserved fields within a PVALIDATE entry must be set to zero as an
> SVSM should be ensuring all reserved fields are zero in order to support

Does "an SVSM" mean here an implementation like Coconut SVSM ?

> future usage of reserved areas based on the protocol version.> 
> Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/boot/startup/sev-shared.c | 1 +
>  arch/x86/coco/sev/core.c           | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
> index ac7dfd21ddd4..a34cd19796f9 100644
> --- a/arch/x86/boot/startup/sev-shared.c
> +++ b/arch/x86/boot/startup/sev-shared.c
> @@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
>  	pc->entry[0].page_size = RMP_PG_SIZE_4K;
>  	pc->entry[0].action    = validate;
>  	pc->entry[0].ignore_cf = 0;
> +	pc->entry[0].rsvd      = 0;
>  	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
>  
>  	/* Protocol 0, Call ID 1 */
> diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
> index 400a6ab75d45..14ef5908fb27 100644
> --- a/arch/x86/coco/sev/core.c
> +++ b/arch/x86/coco/sev/core.c
> @@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
>  		pe->page_size = RMP_PG_SIZE_4K;
>  		pe->action    = action;
>  		pe->ignore_cf = 0;
> +		pe->rsvd      = 0;
>  		pe->pfn       = pfn;
>  
>  		pe++;
> @@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
>  		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
>  		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
>  		pe->ignore_cf = 0;
> +		pe->rsvd      = 0;
>  		pe->pfn       = e->gfn;
>  
>  		pe++;
> 
> base-commit: 4c699535a3d483562354432a945a035f15dfceeb

Re: [sos-linux-ext-patches] [PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

Posted by Tom Lendacky 1 month, 2 weeks ago

On 8/18/25 01:16, Nikunj A. Dadhania wrote:
> On 8/13/2025 8:56 PM, Tom Lendacky wrote:
> 
>> In order to support future versions of the SVSM_CORE_PVALIDATE call,
>> all reserved fields within a PVALIDATE entry must be set to zero as an
>> SVSM should be ensuring all reserved fields are zero in order to support
> 
> Does "an SVSM" mean here an implementation like Coconut SVSM ?

Yes.

Thanks,
Tom

> 
>> future usage of reserved areas based on the protocol version.> 
>> Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>>  arch/x86/boot/startup/sev-shared.c | 1 +
>>  arch/x86/coco/sev/core.c           | 2 ++
>>  2 files changed, 3 insertions(+)
>>
>> diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
>> index ac7dfd21ddd4..a34cd19796f9 100644
>> --- a/arch/x86/boot/startup/sev-shared.c
>> +++ b/arch/x86/boot/startup/sev-shared.c
>> @@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
>>  	pc->entry[0].page_size = RMP_PG_SIZE_4K;
>>  	pc->entry[0].action    = validate;
>>  	pc->entry[0].ignore_cf = 0;
>> +	pc->entry[0].rsvd      = 0;
>>  	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
>>  
>>  	/* Protocol 0, Call ID 1 */
>> diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
>> index 400a6ab75d45..14ef5908fb27 100644
>> --- a/arch/x86/coco/sev/core.c
>> +++ b/arch/x86/coco/sev/core.c
>> @@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
>>  		pe->page_size = RMP_PG_SIZE_4K;
>>  		pe->action    = action;
>>  		pe->ignore_cf = 0;
>> +		pe->rsvd      = 0;
>>  		pe->pfn       = pfn;
>>  
>>  		pe++;
>> @@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
>>  		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
>>  		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
>>  		pe->ignore_cf = 0;
>> +		pe->rsvd      = 0;
>>  		pe->pfn       = e->gfn;
>>  
>>  		pe++;
>>
>> base-commit: 4c699535a3d483562354432a945a035f15dfceeb
>

Re: [PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

Posted by Joerg Roedel 1 month, 2 weeks ago

On Wed, Aug 13, 2025 at 10:26:59AM -0500, Tom Lendacky wrote:
> In order to support future versions of the SVSM_CORE_PVALIDATE call,
> all reserved fields within a PVALIDATE entry must be set to zero as an
> SVSM should be ensuring all reserved fields are zero in order to support
> future usage of reserved areas based on the protocol version.
> 
> Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>

Reviewed-by: Joerg Roedel <joerg.roedel@amd.com>

> ---
>  arch/x86/boot/startup/sev-shared.c | 1 +
>  arch/x86/coco/sev/core.c           | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
> index ac7dfd21ddd4..a34cd19796f9 100644
> --- a/arch/x86/boot/startup/sev-shared.c
> +++ b/arch/x86/boot/startup/sev-shared.c
> @@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
>  	pc->entry[0].page_size = RMP_PG_SIZE_4K;
>  	pc->entry[0].action    = validate;
>  	pc->entry[0].ignore_cf = 0;
> +	pc->entry[0].rsvd      = 0;
>  	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
>  
>  	/* Protocol 0, Call ID 1 */
> diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
> index 400a6ab75d45..14ef5908fb27 100644
> --- a/arch/x86/coco/sev/core.c
> +++ b/arch/x86/coco/sev/core.c
> @@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
>  		pe->page_size = RMP_PG_SIZE_4K;
>  		pe->action    = action;
>  		pe->ignore_cf = 0;
> +		pe->rsvd      = 0;
>  		pe->pfn       = pfn;
>  
>  		pe++;
> @@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
>  		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
>  		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
>  		pe->ignore_cf = 0;
> +		pe->rsvd      = 0;
>  		pe->pfn       = e->gfn;
>  
>  		pe++;
> 
> base-commit: 4c699535a3d483562354432a945a035f15dfceeb
> -- 
> 2.46.2
>