From: Brijesh Singh <brijesh.singh@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
Signed-off-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
---
hw/i386/pc_sysfw.c | 4 ++++
include/hw/i386/pc.h | 26 ++++++++++++++++++++++++++
target/i386/sev.c | 31 +++++++++++++++++++++++++++++++
target/i386/sev.h | 2 ++
4 files changed, 63 insertions(+)
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index ac88ad4eb9..048d0919c1 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -260,6 +260,10 @@ void x86_firmware_configure(void *ptr, int size)
pc_system_parse_ovmf_flash(ptr, size);
if (sev_enabled()) {
+
+ /* Copy the SEV metadata table (if exist) */
+ pc_system_parse_sev_metadata(ptr, size);
+
ret = sev_es_save_reset_vector(ptr, size);
if (ret) {
error_report("failed to locate and/or save reset vector");
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index ad9c3d9ba8..c653b8eeb2 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);
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 2ca9a86bf3..d9d1d97f0c 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -611,6 +611,37 @@ SevCapability *qmp_query_sev_capabilities(Error **errp)
return sev_get_capabilities(errp);
}
+static OvmfSevMetadata *ovmf_sev_metadata_table;
+
+#define OVMF_SEV_META_DATA_GUID "dc886566-984a-4798-A75e-5585a7bf67cc"
+typedef struct __attribute__((__packed__)) OvmfSevMetadataOffset {
+ uint32_t offset;
+} OvmfSevMetadataOffset;
+
+OvmfSevMetadata *pc_system_get_ovmf_sev_metadata_ptr(void)
+{
+ return ovmf_sev_metadata_table;
+}
+
+void pc_system_parse_sev_metadata(uint8_t *flash_ptr, size_t flash_size)
+{
+ OvmfSevMetadata *metadata;
+ OvmfSevMetadataOffset *data;
+
+ if (!pc_system_ovmf_table_find(OVMF_SEV_META_DATA_GUID, (uint8_t **)&data,
+ NULL)) {
+ return;
+ }
+
+ metadata = (OvmfSevMetadata *)(flash_ptr + flash_size - data->offset);
+ if (memcmp(metadata->signature, "ASEV", 4) != 0) {
+ return;
+ }
+
+ ovmf_sev_metadata_table = g_malloc(metadata->len);
+ memcpy(ovmf_sev_metadata_table, metadata, metadata->len);
+}
+
static SevAttestationReport *sev_get_attestation_report(const char *mnonce,
Error **errp)
{
diff --git a/target/i386/sev.h b/target/i386/sev.h
index 5dc4767b1e..cc12824dd6 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -66,4 +66,6 @@ int sev_inject_launch_secret(const char *hdr, const char *secret,
int sev_es_save_reset_vector(void *flash_ptr, uint64_t flash_size);
void sev_es_set_reset_vector(CPUState *cpu);
+void pc_system_parse_sev_metadata(uint8_t *flash_ptr, size_t flash_size);
+
#endif
--
2.34.1
