lkml.org 
[lkml]   [2021]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] KVM: x86: Exit to userspace when kvm_check_nested_events fails
Date
Paolo Bonzini <pbonzini@redhat.com> writes:

> From: Jim Mattson <jmattson@google.com>
>
> 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;
> + 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;

Shouldn't we also change kvm_arch_vcpu_runnable() and check
'kvm_vcpu_running() > 0' now?

--
Vitaly

\
 
 \ /
  Last update: 2021-07-28 14:40    [W:0.118 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site