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| author | Prasad Pandit <pjp@fedoraproject.org> | 2024-01-03 08:53:43 +0100 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-01-31 16:35:07 +0100 |
| commit | 6231c9e1a9f35b535c66709aa8a6eda40dbc4132 (patch) | |
| tree | 861d45dcf4ab2792e7f67f00aa0513238d2ad856 /arch/x86/kvm/x86.c | |
| parent | Linux 6.8-rc2 (diff) | |
| download | linux-6231c9e1a9f35b535c66709aa8a6eda40dbc4132.tar.xz linux-6231c9e1a9f35b535c66709aa8a6eda40dbc4132.zip | |
KVM: x86: make KVM_REQ_NMI request iff NMI pending for vcpu
kvm_vcpu_ioctl_x86_set_vcpu_events() routine makes 'KVM_REQ_NMI'
request for a vcpu even when its 'events->nmi.pending' is zero.
Ex:
qemu_thread_start
kvm_vcpu_thread_fn
qemu_wait_io_event
qemu_wait_io_event_common
process_queued_cpu_work
do_kvm_cpu_synchronize_post_init/_reset
kvm_arch_put_registers
kvm_put_vcpu_events (cpu, level=[2|3])
This leads vCPU threads in QEMU to constantly acquire & release the
global mutex lock, delaying the guest boot due to lock contention.
Add check to make KVM_REQ_NMI request only if vcpu has NMI pending.
Fixes: bdedff263132 ("KVM: x86: Route pending NMIs from userspace through process_nmi()")
Cc: stable@vger.kernel.org
Signed-off-by: Prasad Pandit <pjp@fedoraproject.org>
Link: https://lore.kernel.org/r/20240103075343.549293-1-ppandit@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 363b1c080205..25bc52cdf8f4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5454,7 +5454,8 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, if (events->flags & KVM_VCPUEVENT_VALID_NMI_PENDING) { vcpu->arch.nmi_pending = 0; atomic_set(&vcpu->arch.nmi_queued, events->nmi.pending); - kvm_make_request(KVM_REQ_NMI, vcpu); + if (events->nmi.pending) + kvm_make_request(KVM_REQ_NMI, vcpu); } static_call(kvm_x86_set_nmi_mask)(vcpu, events->nmi.masked); |