On Wed, Jan 03, 2024, Ashish Kalra wrote:
> On 1/3/2024 3:10 PM, Sean Christopherson wrote:
> > > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > > > index d0c580607f00..bfac6d17462a 100644
> > > > --- a/arch/x86/kvm/svm/sev.c
> > > > +++ b/arch/x86/kvm/svm/sev.c
> > > > @@ -143,8 +143,20 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
> > > > static int sev_asid_new(struct kvm_sev_info *sev)
> > > > {
> > > > - int asid, min_asid, max_asid, ret;
> > > > + /*
> > > > + * SEV-enabled guests must use asid from min_sev_asid to max_sev_asid.
> > > > + * SEV-ES-enabled guest can use from 1 to min_sev_asid - 1. Note, the
> > > > + * min ASID can end up larger than the max if basic SEV support is
> > > > + * effectively disabled by disallowing use of ASIDs for SEV guests.
> > > > + */
> > > > + unsigned int min_asid = sev->es_active ? 1 : min_sev_asid;
> > > > + unsigned int max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
> > > > + unsigned int asid;
> > > > bool retry = true;
> > > > + int ret;
> > > > +
> > > > + if (min_asid > max_asid)
> > > > + return -ENOTTY;
> > > This will still return -EBUSY to user.
> > Huh? The above is obviously -ENOTTY, and I don't see anything in the call stack
> > that will convert it to -EBUSY.
>
> Actually, sev_asid_new() returning failure to sev_guest_init() will cause it
> to return -EBUSY to user.
Argh, I see it now. That too should be fixed, e.g.
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index d0c580607f00..79eb11083ad5 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -246,21 +246,20 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
- int asid, ret;
+ int ret;
if (kvm->created_vcpus)
return -EINVAL;
- ret = -EBUSY;
if (unlikely(sev->active))
- return ret;
+ return -EINVAL;
sev->active = true;
sev->es_active = argp->id == KVM_SEV_ES_INIT;
- asid = sev_asid_new(sev);
- if (asid < 0)
+ ret = sev_asid_new(sev);
+ if (ret < 0)
goto e_no_asid;
- sev->asid = asid;
+ sev->asid = ret;
ret = sev_platform_init(&argp->error);
if (ret)
