By code inspection, it was found that multiple calls to KVM_SEV_INIT
could deplete asid bits and overwrite kvm_sev_info's regions_list.
Multiple calls to KVM_SVM_INIT is not likely to occur with QEMU, but this
should likely be fixed anyway.
This code is serialized by kvm->lock.
Fixes: 1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command")
Reported-by: Cfir Cohen <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
---
arch/x86/kvm/svm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6278,6 +6278,9 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
int asid, ret;
ret = -EBUSY;
+ if (unlikely(sev->active))
+ return ret;
+
asid = sev_asid_new();
if (asid < 0)
return ret;
On 1/2/19 2:56 PM, David Rientjes wrote:
> By code inspection, it was found that multiple calls to KVM_SEV_INIT
> could deplete asid bits and overwrite kvm_sev_info's regions_list.
>
> Multiple calls to KVM_SVM_INIT is not likely to occur with QEMU, but this
> should likely be fixed anyway.
>
> This code is serialized by kvm->lock.
>
> Fixes: 1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command")
> Reported-by: Cfir Cohen <[email protected]>
> Signed-off-by: David Rientjes <[email protected]>
Thanks for the patch. Looks good.
Reviewed-by: Brijesh Singh <[email protected]>
2019-01-02 12:56-0800, David Rientjes:
> By code inspection, it was found that multiple calls to KVM_SEV_INIT
> could deplete asid bits and overwrite kvm_sev_info's regions_list.
>
> Multiple calls to KVM_SVM_INIT is not likely to occur with QEMU, but this
> should likely be fixed anyway.
>
> This code is serialized by kvm->lock.
>
> Fixes: 1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command")
> Reported-by: Cfir Cohen <[email protected]>
> Signed-off-by: David Rientjes <[email protected]>
> ---
Applied, thanks.