From: Sean Christopherson seanjc@google.com
commit 9fa1521daafb58d878d03d75f6863a11312fae22 upstream.
Set sev->es_active only after the guts of KVM_SEV_ES_INIT succeeds. If the command fails, e.g. because SEV is already active or there are no available ASIDs, then es_active will be left set even though the VM is not fully SEV-ES capable.
Refactor the code so that "es_active" is passed on the stack instead of being prematurely shoved into sev_info, both to avoid having to unwind sev_info and so that it's more obvious what actually consumes es_active in sev_guest_init() and its helpers.
Fixes: ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest") Cc: stable@vger.kernel.org Cc: Brijesh Singh brijesh.singh@amd.com Cc: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20210331031936.2495277-3-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/sev.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)
--- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -86,7 +86,7 @@ static bool __sev_recycle_asids(int min_ return true; }
-static int sev_asid_new(struct kvm_sev_info *sev) +static int sev_asid_new(bool es_active) { int pos, min_asid, max_asid; bool retry = true; @@ -97,8 +97,8 @@ static int sev_asid_new(struct kvm_sev_i * 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. */ - min_asid = sev->es_active ? 0 : min_sev_asid - 1; - max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid; + min_asid = es_active ? 0 : min_sev_asid - 1; + max_asid = es_active ? min_sev_asid - 1 : max_sev_asid; again: pos = find_next_zero_bit(sev_asid_bitmap, max_sev_asid, min_asid); if (pos >= max_asid) { @@ -178,13 +178,14 @@ static void sev_unbind_asid(struct kvm * static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) { struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + bool es_active = argp->id == KVM_SEV_ES_INIT; int asid, ret;
ret = -EBUSY; if (unlikely(sev->active)) return ret;
- asid = sev_asid_new(sev); + asid = sev_asid_new(es_active); if (asid < 0) return ret;
@@ -193,6 +194,7 @@ static int sev_guest_init(struct kvm *kv goto e_free;
sev->active = true; + sev->es_active = es_active; sev->asid = asid; INIT_LIST_HEAD(&sev->regions_list);
@@ -203,16 +205,6 @@ e_free: return ret; }
-static int sev_es_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) -{ - if (!sev_es) - return -ENOTTY; - - to_kvm_svm(kvm)->sev_info.es_active = true; - - return sev_guest_init(kvm, argp); -} - static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error) { struct sev_data_activate *data; @@ -1059,12 +1051,15 @@ int svm_mem_enc_op(struct kvm *kvm, void mutex_lock(&kvm->lock);
switch (sev_cmd.id) { + case KVM_SEV_ES_INIT: + if (!sev_es) { + r = -ENOTTY; + goto out; + } + fallthrough; case KVM_SEV_INIT: r = sev_guest_init(kvm, &sev_cmd); break; - case KVM_SEV_ES_INIT: - r = sev_es_guest_init(kvm, &sev_cmd); - break; case KVM_SEV_LAUNCH_START: r = sev_launch_start(kvm, &sev_cmd); break;