diff mbox series

[v12,29/46] x86/boot: Add Confidential Computing type to setup_data

Message ID 20220307213356.2797205-30-brijesh.singh@amd.com (mailing list archive)
State New, archived
Headers show
Series Add AMD Secure Nested Paging (SEV-SNP) Guest Support | expand

Commit Message

Brijesh Singh March 7, 2022, 9:33 p.m. UTC 
While launching the encrypted guests, the hypervisor may need to provide
some additional information during the guest boot. When booting under the
EFI based BIOS, the EFI configuration table contains an entry for the
confidential computing blob that contains the required information.

To support booting encrypted guests on non-EFI VM, the hypervisor needs to
pass this additional information to the kernel with a different method.

For this purpose, introduce SETUP_CC_BLOB type in setup_data to hold the
physical address of the confidential computing blob location. The boot
loader or hypervisor may choose to use this method instead of EFI
configuration table. The CC blob location scanning should give preference
to setup_data data over the EFI configuration table.

In AMD SEV-SNP, the CC blob contains the address of the secrets and CPUID
pages. The secrets page includes information such as a VM to PSP
communication key and CPUID page contains PSP filtered CPUID values.
Define the AMD SEV confidential computing blob structure.

While at it, define the EFI GUID for the confidential computing blob.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h            | 18 ++++++++++++++++++
 arch/x86/include/uapi/asm/bootparam.h |  1 +
 include/linux/efi.h                   |  1 +
 3 files changed, 20 insertions(+)

Comments

Thomas Gleixner April 6, 2022, 9:19 p.m. UTC | #1 
On Mon, Mar 07 2022 at 15:33, Brijesh Singh wrote:
>  
> +/*
> + * AMD SEV Confidential computing blob structure. The structure is
> + * defined in OVMF UEFI firmware header:
> + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
> + */
> +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
> +struct cc_blob_sev_info {
> +	u32 magic;
> +	u16 version;
> +	u16 reserved;
> +	u64 secrets_phys;
> +	u32 secrets_len;
> +	u32 rsvd1;
> +	u64 cpuid_phys;
> +	u32 cpuid_len;
> +	u32 rsvd2;
> +};

Shouldn't this be packed?

Thanks,

        tglx
Borislav Petkov April 7, 2022, 2:47 p.m. UTC | #2 
On Wed, Apr 06, 2022 at 11:19:10PM +0200, Thomas Gleixner wrote:
> On Mon, Mar 07 2022 at 15:33, Brijesh Singh wrote:
> >  
> > +/*
> > + * AMD SEV Confidential computing blob structure. The structure is
> > + * defined in OVMF UEFI firmware header:
> > + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
> > + */
> > +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
> > +struct cc_blob_sev_info {
> > +	u32 magic;
> > +	u16 version;
> > +	u16 reserved;
> > +	u64 secrets_phys;
> > +	u32 secrets_len;
> > +	u32 rsvd1;
> > +	u64 cpuid_phys;
> > +	u32 cpuid_len;
> > +	u32 rsvd2;
> > +};
> 
> Shouldn't this be packed?

Done.

Thx.
Brijesh Singh April 7, 2022, 2:57 p.m. UTC | #3 
On 4/6/22 16:19, Thomas Gleixner wrote:
> On Mon, Mar 07 2022 at 15:33, Brijesh Singh wrote:
>>   
>> +/*
>> + * AMD SEV Confidential computing blob structure. The structure is
>> + * defined in OVMF UEFI firmware header:
>> + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
>> + */
>> +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
>> +struct cc_blob_sev_info {
>> +	u32 magic;
>> +	u16 version;
>> +	u16 reserved;
>> +	u64 secrets_phys;
>> +	u32 secrets_len;
>> +	u32 rsvd1;
>> +	u64 cpuid_phys;
>> +	u32 cpuid_len;
>> +	u32 rsvd2;
>> +};
> 
> Shouldn't this be packed?
> 

Yep, to avoid any additional compiler alignment we should pack it.

thanks
H. Peter Anvin July 17, 2022, 5:08 a.m. UTC | #4 
On April 7, 2022 7:57:22 AM PDT, Brijesh Singh <brijesh.singh@amd.com> wrote:
>
>
>On 4/6/22 16:19, Thomas Gleixner wrote:
>> On Mon, Mar 07 2022 at 15:33, Brijesh Singh wrote:
>>>   
>>> +/*
>>> + * AMD SEV Confidential computing blob structure. The structure is
>>> + * defined in OVMF UEFI firmware header:
>>> + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
>>> + */
>>> +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
>>> +struct cc_blob_sev_info {
>>> +	u32 magic;
>>> +	u16 version;
>>> +	u16 reserved;
>>> +	u64 secrets_phys;
>>> +	u32 secrets_len;
>>> +	u32 rsvd1;
>>> +	u64 cpuid_phys;
>>> +	u32 cpuid_len;
>>> +	u32 rsvd2;
>>> +};
>> 
>> Shouldn't this be packed?
>> 
>
>Yep, to avoid any additional compiler alignment we should pack it.
>
>thanks

It shouldn't be *necessary*, any more than it is necessary for kernel-user space structures, since EFI is a C-based ABI. On x86 it doesn't hurt, either, though, so might as well.
diff mbox series

Patch

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index a3203b2caaca..1a7e21bb6eea 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -42,6 +42,24 @@  struct es_em_ctxt {
 	struct es_fault_info fi;
 };
 
+/*
+ * AMD SEV Confidential computing blob structure. The structure is
+ * defined in OVMF UEFI firmware header:
+ * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
+ */
+#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
+struct cc_blob_sev_info {
+	u32 magic;
+	u16 version;
+	u16 reserved;
+	u64 secrets_phys;
+	u32 secrets_len;
+	u32 rsvd1;
+	u64 cpuid_phys;
+	u32 cpuid_len;
+	u32 rsvd2;
+};
+
 void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code);
 
 static inline u64 lower_bits(u64 val, unsigned int bits)
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index b25d3f82c2f3..1ac5acca72ce 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -10,6 +10,7 @@ 
 #define SETUP_EFI			4
 #define SETUP_APPLE_PROPERTIES		5
 #define SETUP_JAILHOUSE			6
+#define SETUP_CC_BLOB			7
 
 #define SETUP_INDIRECT			(1<<31)
 
diff --git a/include/linux/efi.h b/include/linux/efi.h
index ccd4d3f91c98..984aa688997a 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -390,6 +390,7 @@  void efi_native_runtime_setup(void);
 #define EFI_CERT_SHA256_GUID			EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
 #define EFI_CERT_X509_GUID			EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72)
 #define EFI_CERT_X509_SHA256_GUID		EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed)
+#define EFI_CC_BLOB_GUID			EFI_GUID(0x067b1f5f, 0xcf26, 0x44c5, 0x85, 0x54, 0x93, 0xd7, 0x77, 0x91, 0x2d, 0x42)
 
 /*
  * This GUID is used to pass to the kernel proper the struct screen_info