x86/boot: Add Confidential Computing type to setup_data

While launching encrypted guests, the hypervisor may need to provide
some additional information during the guest boot. When booting under an
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 VMs, the hypervisor
needs to pass this additional information to the guest kernel using 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 an
EFI configuration table. The CC blob location scanning should give
preference to a setup_data blob over an 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 the 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.

  [ bp: Massage commit message, mark struct __packed. ]

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220307213356.2797205-30-brijesh.singh@amd.com

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index a3203b2caacae2ed58a0d5f032dba3a1d632854a..8c934bda2a90a8b04bec9de7b0afcb7a51508e30 100644 (file)
--- 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;
+} __packed;
+
 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 b25d3f82c2f36a9a210863d0540f2adc5744238a..1ac5acca72ceb3a4a8d4813f09abf23b60a7aa36 100644 (file)
--- 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 ccd4d3f91c98c247cb772df2a94e104b231a6bf7..984aa688997a4d7f2f3ac8f56d4341e435934d04 100644 (file)
--- 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