lkml.org 
[lkml]   [2021]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH 1/3] KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs
From
Use the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting
VMSAs for SEV, which effectively switches to use online_vcpus instead of
created_vcpus. This fixes a possible null-pointer dereference as
created_vcpus does not guarantee a vCPU exists, since it is updated at
the very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the
bulk of vCPU creation to run in parallel, while still correctly
restricting the max number of max vCPUs.

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>
---
arch/x86/kvm/svm/sev.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 83e00e524513..6481d7165701 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -564,6 +564,7 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct sev_data_launch_update_vmsa *vmsa;
+ struct kvm_vcpu *vcpu;
int i, ret;

if (!sev_es_guest(kvm))
@@ -573,8 +574,8 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
if (!vmsa)
return -ENOMEM;

- for (i = 0; i < kvm->created_vcpus; i++) {
- struct vcpu_svm *svm = to_svm(kvm->vcpus[i]);
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ struct vcpu_svm *svm = to_svm(vcpu);

/* Perform some pre-encryption checks against the VMSA */
ret = sev_es_sync_vmsa(svm);
--
2.31.0.291.g576ba9dcdaf-goog
\
 
 \ /
  Last update: 2021-03-31 05:21    [W:0.033 / U:0.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site