From: Sean Christopherson seanjc@google.com
[ Upstream commit 3b1902b87bf11f1c6a84368470dc13da6f3da3bd ]
Zero out the array of VMCB pointers so that pre_sev_run() won't see garbage when querying the array to detect when an SEV ASID is being associated with a new VMCB. In practice, reading random values is all but guaranteed to be benign as a false negative (which is extremely unlikely on its own) can only happen on CPU0 on the first VMRUN and would only cause KVM to skip the ASID flush. For anything bad to happen, a previous instance of KVM would have to exit without flushing the ASID, _and_ KVM would have to not flush the ASID at any time while building the new SEV guest.
Cc: Borislav Petkov bp@suse.de Reviewed-by: Tom Lendacky thomas.lendacky@amd.com Reviewed-by: Brijesh Singh brijesh.singh@amd.com Fixes: 70cd94e60c73 ("KVM: SVM: VMRUN should use associated ASID when SEV is enabled") Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20210422021125.3417167-2-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kvm/svm/svm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9c260c73f334..d5620361eae7 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -564,9 +564,8 @@ static int svm_cpu_init(int cpu) clear_page(page_address(sd->save_area));
if (svm_sev_enabled()) { - sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1, - sizeof(void *), - GFP_KERNEL); + sd->sev_vmcbs = kcalloc(max_sev_asid + 1, sizeof(void *), + GFP_KERNEL); if (!sd->sev_vmcbs) goto free_save_area; }