[RFC PATCH 5/6] i386/sev: add support to encrypt BIOS when SEV-SNP is enabled

Brijesh Singh
2021-07-09T21:56:18Z

The KVM_SEV_SNP_LAUNCH_UPDATE command is used for encrypting the bios
image used for booting the SEV-SNP guest.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
target/i386/sev.c | 33 ++++++++++++++++++++++++++++++++-
target/i386/trace-events | 1 +
2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 259408a8f1..41dcb084d1 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -883,6 +883,30 @@ out:
return ret;
}

+static int
+sev_snp_launch_update(SevGuestState *sev, uint8_t *addr, uint64_t len, int type)
+{
+ int ret, fw_error;
+ struct kvm_sev_snp_launch_update update = {};
+
+ if (!addr || !len) {
+ return 1;
+ }
+
+ update.uaddr = (__u64)(unsigned long)addr;
+ update.len = len;
+ update.page_type = type;
+ trace_kvm_sev_snp_launch_update(addr, len, type);
+ ret = sev_ioctl(sev->sev_fd, KVM_SEV_SNP_LAUNCH_UPDATE,
+ &update, &fw_error);
+ if (ret) {
+ error_report("%s: SNP_LAUNCH_UPDATE ret=%d fw_error=%d '%s'",
+ __func__, ret, fw_error, fw_error_to_str(fw_error));
+ }
+
+ return ret;
+}
+
static int
sev_launch_update_data(SevGuestState *sev, uint8_t *addr, uint64_t len)
{
@@ -1161,7 +1185,14 @@ sev_encrypt_flash(uint8_t *ptr, uint64_t len, Error **errp)

/* if SEV is in update state then encrypt the data else do nothing */
if (sev_check_state(sev_guest, SEV_STATE_LAUNCH_UPDATE)) {
- int ret = sev_launch_update_data(sev_guest, ptr, len);
+ int ret;
+
+ if (sev_snp_enabled()) {
+ ret = sev_snp_launch_update(sev_guest, ptr, len,
+ KVM_SEV_SNP_PAGE_TYPE_NORMAL);
+ } else {
+ ret = sev_launch_update_data(sev_guest, ptr, len);
+ }
if (ret < 0) {
error_setg(errp, "failed to encrypt pflash rom");
return ret;
diff --git a/target/i386/trace-events b/target/i386/trace-events
index 18cc14b956..0c2d250206 100644
--- a/target/i386/trace-events
+++ b/target/i386/trace-events
@@ -12,3 +12,4 @@ kvm_sev_launch_finish(void) ""
kvm_sev_launch_secret(uint64_t hpa, uint64_t hva, uint64_t secret, int len) "hpa 0x%" PRIx64 " hva 0x%" PRIx64 " data 0x%" PRIx64 " len %d"
kvm_sev_attestation_report(const char *mnonce, const char *data) "mnonce %s data %s"
kvm_sev_snp_launch_start(uint64_t policy) "policy 0x%" PRIx64
+kvm_sev_snp_launch_update(void *addr, uint64_t len, int type) "addr %p len 0x%" PRIx64 " type %d"
--
2.17.1