[RFC PATCH 3/6] i386/sev: initialize SNP context

Brijesh Singh
2021-07-09T21:56:16Z

When SEV-SNP is enabled, the KVM_SNP_INIT command is used to initialize
the platform. The command checks whether SNP is enabled in the KVM, if
enabled then it allocate a new ASID from the SNP pool and calls the
firmware to initialize the all the resources.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
target/i386/sev.c | 24 +++++++++++++++++++++---
target/i386/sev_i386.h | 1 +
2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 6b238ef969..84ae244af0 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -583,10 +583,17 @@ sev_enabled(void)
return !!sev_guest;
}

+bool
+sev_snp_enabled(void)
+{
+ return sev_guest->snp;
+}
+
bool
sev_es_enabled(void)
{
- return sev_enabled() && (sev_guest->policy & SEV_POLICY_ES);
+ return sev_snp_enabled() ||
+ (sev_enabled() && (sev_guest->policy & SEV_POLICY_ES));
}

uint64_t
@@ -1008,6 +1015,7 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
uint32_t ebx;
uint32_t host_cbitpos;
struct sev_user_data_status status = {};
+ void *init_args = NULL;

if (!sev) {
return 0;
@@ -1061,7 +1069,17 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
sev->api_major = status.api_major;
sev->api_minor = status.api_minor;

- if (sev_es_enabled()) {
+ if (sev_snp_enabled()) {
+ if (!kvm_kernel_irqchip_allowed()) {
+ error_report("%s: SEV-SNP guests require in-kernel irqchip support",
+ __func__);
+ goto err;
+ }
+
+ cmd = KVM_SEV_SNP_INIT;
+ init_args = (void *)&sev->snp_config.init;
+
+ } else if (sev_es_enabled()) {
if (!kvm_kernel_irqchip_allowed()) {
error_report("%s: SEV-ES guests require in-kernel irqchip support",
__func__);
@@ -1080,7 +1098,7 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
}

trace_kvm_sev_init();
- ret = sev_ioctl(sev->sev_fd, cmd, NULL, &fw_error);
+ ret = sev_ioctl(sev->sev_fd, cmd, init_args, &fw_error);
if (ret) {
error_setg(errp, "%s: failed to initialize ret=%d fw_error=%d '%s'",
__func__, ret, fw_error, fw_error_to_str(fw_error));
diff --git a/target/i386/sev_i386.h b/target/i386/sev_i386.h
index ae6d840478..e0e1a599be 100644
--- a/target/i386/sev_i386.h
+++ b/target/i386/sev_i386.h
@@ -29,6 +29,7 @@
#define SEV_POLICY_SEV 0x20

extern bool sev_es_enabled(void);
+extern bool sev_snp_enabled(void);
extern uint64_t sev_get_me_mask(void);
extern SevInfo *sev_get_info(void);
extern uint32_t sev_get_cbit_position(void);
--
2.17.1