From: Pankaj Gupta <pankaj.gupta@amd.com>
Some aspects of the init routine SEV are specific to SEV and not
applicable for SNP guests, so move the SEV-specific bits into
separate class method and retain only the common functionality.
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Message-ID: <20240530111643.1091816-10-pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/sev.c | 72 +++++++++++++++++++++++++++++++++--------------
1 file changed, 51 insertions(+), 21 deletions(-)
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 4edfedc1393..5519de1c6b2 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -73,6 +73,7 @@ struct SevCommonStateClass {
/* public */
int (*launch_start)(SevCommonState *sev_common);
void (*launch_finish)(SevCommonState *sev_common);
+ int (*kvm_init)(ConfidentialGuestSupport *cgs, Error **errp);
};
/**
@@ -882,7 +883,7 @@ out:
return sev_common->kvm_type;
}
-static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
+static int sev_common_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
{
SevCommonState *sev_common = SEV_COMMON(cgs);
char *devname;
@@ -892,12 +893,6 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
struct sev_user_data_status status = {};
SevCommonStateClass *klass = SEV_COMMON_GET_CLASS(cgs);
- ret = ram_block_discard_disable(true);
- if (ret) {
- error_report("%s: cannot disable RAM discard", __func__);
- return -1;
- }
-
sev_common->state = SEV_STATE_UNINIT;
host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL);
@@ -911,7 +906,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
if (host_cbitpos != sev_common->cbitpos) {
error_setg(errp, "%s: cbitpos check failed, host '%d' requested '%d'",
__func__, host_cbitpos, sev_common->cbitpos);
- goto err;
+ return -1;
}
/*
@@ -924,7 +919,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
error_setg(errp, "%s: reduced_phys_bits check failed,"
" it should be in the range of 1 to 63, requested '%d'",
__func__, sev_common->reduced_phys_bits);
- goto err;
+ return -1;
}
devname = object_property_get_str(OBJECT(sev_common), "sev-device", NULL);
@@ -933,7 +928,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
error_setg(errp, "%s: Failed to open %s '%s'", __func__,
devname, strerror(errno));
g_free(devname);
- goto err;
+ return -1;
}
g_free(devname);
@@ -943,7 +938,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
error_setg(errp, "%s: failed to get platform status ret=%d "
"fw_error='%d: %s'", __func__, ret, fw_error,
fw_error_to_str(fw_error));
- goto err;
+ return -1;
}
sev_common->build_id = status.build;
sev_common->api_major = status.api_major;
@@ -953,7 +948,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
if (!kvm_kernel_irqchip_allowed()) {
error_setg(errp, "%s: SEV-ES guests require in-kernel irqchip"
"support", __func__);
- goto err;
+ return -1;
}
}
@@ -962,7 +957,7 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
error_setg(errp, "%s: guest policy requires SEV-ES, but "
"host SEV-ES support unavailable",
__func__);
- goto err;
+ return -1;
}
}
@@ -980,25 +975,59 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
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));
- goto err;
+ return -1;
}
ret = klass->launch_start(sev_common);
if (ret) {
error_setg(errp, "%s: failed to create encryption context", __func__);
- goto err;
+ return -1;
+ }
+
+ if (klass->kvm_init && klass->kvm_init(cgs, errp)) {
+ return -1;
}
- ram_block_notifier_add(&sev_ram_notifier);
- qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
qemu_add_vm_change_state_handler(sev_vm_state_change, sev_common);
cgs->ready = true;
return 0;
-err:
- ram_block_discard_disable(false);
- return -1;
+}
+
+static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
+{
+ int ret;
+
+ /*
+ * SEV/SEV-ES rely on pinned memory to back guest RAM so discarding
+ * isn't actually possible. With SNP, only guest_memfd pages are used
+ * for private guest memory, so discarding of shared memory is still
+ * possible..
+ */
+ ret = ram_block_discard_disable(true);
+ if (ret) {
+ error_setg(errp, "%s: cannot disable RAM discard", __func__);
+ return -1;
+ }
+
+ /*
+ * SEV uses these notifiers to register/pin pages prior to guest use,
+ * but SNP relies on guest_memfd for private pages, which has its
+ * own internal mechanisms for registering/pinning private memory.
+ */
+ ram_block_notifier_add(&sev_ram_notifier);
+
+ /*
+ * The machine done notify event is used for SEV guests to get the
+ * measurement of the encrypted images. When SEV-SNP is enabled, the
+ * measurement is part of the guest attestation process where it can
+ * be collected without any reliance on the VMM. So skip registering
+ * the notifier for SNP in favor of using guest attestation instead.
+ */
+ qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
+
+ return 0;
}
int
@@ -1397,7 +1426,7 @@ sev_common_class_init(ObjectClass *oc, void *data)
ConfidentialGuestSupportClass *klass = CONFIDENTIAL_GUEST_SUPPORT_CLASS(oc);
X86ConfidentialGuestClass *x86_klass = X86_CONFIDENTIAL_GUEST_CLASS(oc);
- klass->kvm_init = sev_kvm_init;
+ klass->kvm_init = sev_common_kvm_init;
x86_klass->kvm_type = sev_kvm_type;
object_class_property_add_str(oc, "sev-device",
@@ -1486,6 +1515,7 @@ sev_guest_class_init(ObjectClass *oc, void *data)
klass->launch_start = sev_launch_start;
klass->launch_finish = sev_launch_finish;
+ klass->kvm_init = sev_kvm_init;
object_class_property_add_str(oc, "dh-cert-file",
sev_guest_get_dh_cert_file,
--
2.45.1