hw/i386/sev: Add function to get SEV metadata from OVMF header

A recent version of OVMF expanded the reset vector GUID list to add
SEV-specific metadata GUID. The SEV metadata describes the reserved
memory regions such as the secrets and CPUID page used during the SEV-SNP
guest launch.

The pc_system_get_ovmf_sev_metadata_ptr() is used to retieve the SEV
metadata pointer from the OVMF GUID list.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Message-ID: <20240530111643.1091816-19-pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index ad9c3d9..c653b8e 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -164,6 +164,32 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, int level);
 #define PCI_HOST_ABOVE_4G_MEM_SIZE     "above-4g-mem-size"
 #define PCI_HOST_PROP_SMM_RANGES       "smm-ranges"
 
+typedef enum {
+    SEV_DESC_TYPE_UNDEF,
+    /* The section contains the region that must be validated by the VMM. */
+    SEV_DESC_TYPE_SNP_SEC_MEM,
+    /* The section contains the SNP secrets page */
+    SEV_DESC_TYPE_SNP_SECRETS,
+    /* The section contains address that can be used as a CPUID page */
+    SEV_DESC_TYPE_CPUID,
+
+} ovmf_sev_metadata_desc_type;
+
+typedef struct __attribute__((__packed__)) OvmfSevMetadataDesc {
+    uint32_t base;
+    uint32_t len;
+    ovmf_sev_metadata_desc_type type;
+} OvmfSevMetadataDesc;
+
+typedef struct __attribute__((__packed__)) OvmfSevMetadata {
+    uint8_t signature[4];
+    uint32_t len;
+    uint32_t version;
+    uint32_t num_desc;
+    OvmfSevMetadataDesc descs[];
+} OvmfSevMetadata;
+
+OvmfSevMetadata *pc_system_get_ovmf_sev_metadata_ptr(void);
 
 void pc_pci_as_mapping_init(MemoryRegion *system_memory,
                             MemoryRegion *pci_address_space);