On Wed, Mar 20, 2024 at 03:39:36AM -0500,
Michael Roth <michael.roth@xxxxxxx> wrote:
> 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>
> ---
> hw/i386/pc_sysfw_ovmf.c | 33 +++++++++++++++++++++++++++++++++
> include/hw/i386/pc.h | 26 ++++++++++++++++++++++++++
> 2 files changed, 59 insertions(+)
>
> diff --git a/hw/i386/pc_sysfw_ovmf.c b/hw/i386/pc_sysfw_ovmf.c
> index 07a4c267fa..32efa34614 100644
> --- a/hw/i386/pc_sysfw_ovmf.c
> +++ b/hw/i386/pc_sysfw_ovmf.c
> @@ -35,6 +35,31 @@ static const int bytes_after_table_footer = 32;
> static bool ovmf_flash_parsed;
> static uint8_t *ovmf_table;
> static int ovmf_table_len;
> +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;
> +
> +static 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);
> +}
>
> void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size)
> {
> @@ -90,6 +115,9 @@ void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size)
> */
> memcpy(ovmf_table, ptr - tot_len, tot_len);
> ovmf_table += tot_len;
> +
> + /* Copy the SEV metadata table (if exist) */
> + pc_system_parse_sev_metadata(flash_ptr, flash_size);
> }
Can we move this call to x86_firmware_configure() @ pc_sysfw.c, and move sev
specific bits to somewhere to sev specific file? We don't have to parse sev
metadata for non-SEV case, right?
We don't have to touch common ovmf file. It also will be consistent with tdx
case. TDX patch series adds tdx_parse_tdvf() to x86_firmware_configure().
thanks,
>
> /**
> @@ -159,3 +187,8 @@ bool pc_system_ovmf_table_find(const char *entry, uint8_t **data,
> }
> return false;
> }
> +
> +OvmfSevMetadata *pc_system_get_ovmf_sev_metadata_ptr(void)
> +{
> + return ovmf_sev_metadata_table;
> +}
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index fb1d4106e5..df9a61540d 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -163,6 +163,32 @@ 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);
> --
> 2.25.1
>
>
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
