On 6/13/22 23:33, Alper Gun wrote:
On Mon, Jun 13, 2022 at 4:15 PM Ashish Kalra <ashkalra@xxxxxxx> wrote:
Hello Alper,
On 6/13/22 20:58, Alper Gun wrote:
static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
+ bool es_active = (argp->id == KVM_SEV_ES_INIT || argp->id == KVM_SEV_SNP_INIT);
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
- bool es_active = argp->id == KVM_SEV_ES_INIT;
+ bool snp_active = argp->id == KVM_SEV_SNP_INIT;
int asid, ret;
if (kvm->created_vcpus)
@@ -249,12 +269,22 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
sev->es_active = es_active;
+ sev->snp_active = snp_active;
asid = sev_asid_new(sev);
if (asid < 0)
goto e_no_asid;
sev->asid = asid;
- ret = sev_platform_init(&argp->error);
+ if (snp_active) {
+ ret = verify_snp_init_flags(kvm, argp);
+ if (ret)
+ goto e_free;
+
+ ret = sev_snp_init(&argp->error);
+ } else {
+ ret = sev_platform_init(&argp->error);
After SEV INIT_EX support patches, SEV may be initialized in the platform late.
In my tests, if SEV has not been initialized in the platform yet, SNP
VMs fail with SEV_DF_FLUSH required error. I tried calling
SEV_DF_FLUSH right after the SNP platform init but this time it failed
later on the SNP launch update command with SEV_RET_INVALID_PARAM
error. Looks like there is another dependency on SEV platform
initialization.
Calling sev_platform_init for SNP VMs fixes the problem in our tests.
Trying to get some more context for this issue.
When you say after SEV_INIT_EX support patches, SEV may be initialized
in the platform late, do you mean sev_pci_init()->sev_snp_init() ...
sev_platform_init() code path has still not executed on the host BSP ?
Correct, INIT_EX requires the file system to be ready and there is a
ccp module param to call it only when needed.
MODULE_PARM_DESC(psp_init_on_probe, " if true, the PSP will be
initialized on module init. Else the PSP will be initialized on the
first command requiring it");
If this module param is false, it won't initialize SEV on the platform
until the first SEV VM.
Ok, that makes sense.
So the fix will be to call sev_platform_init() unconditionally here in
sev_guest_init(), and both sev_snp_init() and sev_platform_init() are
protected from being called again, so there won't be any issues if these
functions are invoked again at SNP/SEV VM launch if they have been
invoked earlier during module init.
Thanks, Ashish
