diff options
author | Sean Christopherson <seanjc@google.com> | 2021-12-21 10:37:00 -0500 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-21 12:39:03 -0500 |
commit | fdba608f15e2427419997b0898750a49a735afcb (patch) | |
tree | a85a6ebf72671cfa68f5f531e481690982013234 /arch/x86/kvm/vmx/vmx.c | |
parent | ab1ef34416a65ba11f66ae6435fcf0251cb46fd4 (diff) | |
download | linux-fdba608f15e2427419997b0898750a49a735afcb.tar.bz2 |
KVM: VMX: Wake vCPU when delivering posted IRQ even if vCPU == this vCPU
Drop a check that guards triggering a posted interrupt on the currently
running vCPU, and more importantly guards waking the target vCPU if
triggering a posted interrupt fails because the vCPU isn't IN_GUEST_MODE.
If a vIRQ is delivered from asynchronous context, the target vCPU can be
the currently running vCPU and can also be blocking, in which case
skipping kvm_vcpu_wake_up() is effectively dropping what is supposed to
be a wake event for the vCPU.
The "do nothing" logic when "vcpu == running_vcpu" mostly works only
because the majority of calls to ->deliver_posted_interrupt(), especially
when using posted interrupts, come from synchronous KVM context. But if
a device is exposed to the guest using vfio-pci passthrough, the VFIO IRQ
and vCPU are bound to the same pCPU, and the IRQ is _not_ configured to
use posted interrupts, wake events from the device will be delivered to
KVM from IRQ context, e.g.
vfio_msihandler()
|
|-> eventfd_signal()
|
|-> ...
|
|-> irqfd_wakeup()
|
|->kvm_arch_set_irq_inatomic()
|
|-> kvm_irq_delivery_to_apic_fast()
|
|-> kvm_apic_set_irq()
This also aligns the non-nested and nested usage of triggering posted
interrupts, and will allow for additional cleanups.
Fixes: 379a3c8ee444 ("KVM: VMX: Optimize posted-interrupt delivery for timer fastpath")
Cc: stable@vger.kernel.org
Reported-by: Longpeng (Mike) <longpeng2@huawei.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-18-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/vmx.c')
-rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5974a88c9d35..0dbf94eb954f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3964,8 +3964,7 @@ static int vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector) if (pi_test_and_set_on(&vmx->pi_desc)) return 0; - if (vcpu != kvm_get_running_vcpu() && - !kvm_vcpu_trigger_posted_interrupt(vcpu, false)) + if (!kvm_vcpu_trigger_posted_interrupt(vcpu, false)) kvm_vcpu_kick(vcpu); return 0; |