From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH] KVM: x86: Exit to userspace when kvm_check_nested_events fails
Date: Wed, 28 Jul 2021 16:24:01 +0000 [thread overview]
Message-ID: <YQGEoRTfGhinO41u@google.com> (raw)
In-Reply-To: <20210728115317.1930332-1-pbonzini@redhat.com>
On Wed, Jul 28, 2021, Paolo Bonzini wrote:
> From: Jim Mattson <jmattson@google.com>
I don't think this is actually from Jim.
> If kvm_check_nested_events fails due to raising an
> EXIT_REASON_INTERNAL_ERROR, propagate it to userspace
> immediately, even if the vCPU would otherwise be sleeping.
> This happens for example when the posted interrupt descriptor
> points outside guest memory.
>
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/x86.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 348452bb16bc..916c976e99ab 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9752,10 +9752,14 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
> return 1;
> }
>
> -static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
> +static inline int kvm_vcpu_running(struct kvm_vcpu *vcpu)
> {
> - if (is_guest_mode(vcpu))
> - kvm_check_nested_events(vcpu);
> + int r;
newline
> + if (is_guest_mode(vcpu)) {
> + r = kvm_check_nested_events(vcpu);
> + if (r < 0 && r != -EBUSY)
> + return r;
> + }
>
> return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
> !vcpu->arch.apf.halted);
> @@ -9770,12 +9774,16 @@ static int vcpu_run(struct kvm_vcpu *vcpu)
> vcpu->arch.l1tf_flush_l1d = true;
>
> for (;;) {
> - if (kvm_vcpu_running(vcpu)) {
> - r = vcpu_enter_guest(vcpu);
> - } else {
> - r = vcpu_block(kvm, vcpu);
> + r = kvm_vcpu_running(vcpu);
> + if (r < 0) {
> + r = 0;
> + break;
> }
>
> + if (r)
> + r = vcpu_enter_guest(vcpu);
> + else
> + r = vcpu_block(kvm, vcpu);
> if (r <= 0)
> break;
>
> --
> 2.27.0
>
prev parent reply other threads:[~2021-07-28 16:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 11:53 [PATCH] KVM: x86: Exit to userspace when kvm_check_nested_events fails Paolo Bonzini
2021-07-28 12:39 ` Vitaly Kuznetsov
2021-07-28 15:55 ` Paolo Bonzini
2021-07-28 17:53 ` Sean Christopherson
2021-08-02 17:06 ` Paolo Bonzini
2021-07-28 16:24 ` Sean Christopherson [this message]
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