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| author | Maxim Levitsky <mlevitsk@redhat.com> | 2022-06-06 21:08:28 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-09 10:52:20 -0400 |
| commit | 18869f26df1a11ed11031dfb7392bc7d774062e8 (patch) | |
| tree | 0675dbb4cce6d273d89d593b459c55044d0e38b7 | |
| parent | 66c768d30e64e1280520f34dbef83419f55f3459 (diff) | |
KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking
On SVM, if preemption happens right after the call to finish_rcuwait
but before call to kvm_arch_vcpu_unblocking on SVM/AVIC, it itself
will re-enable AVIC, and then we will try to re-enable it again
in kvm_arch_vcpu_unblocking which will lead to a warning
in __avic_vcpu_load.
The same problem can happen if the vCPU is preempted right after the call
to kvm_arch_vcpu_blocking but before the call to prepare_to_rcuwait
and in this case, we will end up with AVIC enabled during sleep -
Ooops.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220606180829.102503-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | virt/kvm/kvm_main.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 44c47670447a..a49df8988cd6 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3328,9 +3328,11 @@ bool kvm_vcpu_block(struct kvm_vcpu *vcpu) vcpu->stat.generic.blocking = 1; + preempt_disable(); kvm_arch_vcpu_blocking(vcpu); - prepare_to_rcuwait(wait); + preempt_enable(); + for (;;) { set_current_state(TASK_INTERRUPTIBLE); @@ -3340,9 +3342,11 @@ bool kvm_vcpu_block(struct kvm_vcpu *vcpu) waited = true; schedule(); } - finish_rcuwait(wait); + preempt_disable(); + finish_rcuwait(wait); kvm_arch_vcpu_unblocking(vcpu); + preempt_enable(); vcpu->stat.generic.blocking = 0; |