From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Borislav Petkov <bp@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v3 01/13] KVM: SVM: Zero out the VMCB array used to track SEV ASID association
Date: Fri, 22 Jan 2021 12:21:32 -0800 [thread overview]
Message-ID: <20210122202144.2756381-2-seanjc@google.com> (raw)
In-Reply-To: <20210122202144.2756381-1-seanjc@google.com>
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>
---
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 7ef171790d02..5bd797c7ee60 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -571,9 +571,8 @@ 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;
}
--
2.30.0.280.ga3ce27912f-goog
next prev parent reply other threads:[~2021-01-22 20:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 20:21 [PATCH v3 00/13] KVM: SVM: Misc SEV cleanups Sean Christopherson
2021-01-22 20:21 ` Sean Christopherson [this message]
2021-01-22 20:21 ` [PATCH v3 02/13] KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails Sean Christopherson
2021-01-22 21:09 ` Tom Lendacky
2021-01-22 20:21 ` [PATCH v3 03/13] KVM: SVM: Move SEV module params/variables to sev.c Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 04/13] x86/sev: Drop redundant and potentially misleading 'sev_enabled' Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 05/13] KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 06/13] KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 07/13] KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported) Sean Christopherson
2021-01-22 21:11 ` Tom Lendacky
2021-01-22 20:21 ` [PATCH v3 08/13] KVM: SVM: Unconditionally invoke sev_hardware_teardown() Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 09/13] KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup() Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 10/13] KVM: SVM: Move SEV VMCB tracking allocation to sev.c Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 11/13] KVM: SVM: Drop redundant svm_sev_enabled() helper Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 12/13] KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids() Sean Christopherson
2021-01-22 20:21 ` [PATCH v3 13/13] KVM: SVM: Skip SEV cache flush if no ASIDs have been used Sean Christopherson
2021-01-22 21:16 ` Tom Lendacky
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