4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 3f14a89d1132dcae3c8ce6721c6ef51f6e6d9b5f ]
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 cfir@google.com Signed-off-by: David Rientjes rientjes@google.com Signed-off-by: Radim Krčmář rkrcmar@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 index 11641d9e7f6f..13baba9d1cc1 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -6255,6 +6255,9 @@ 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;