UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

KVM: SVM: extract avic_ring_doorbell 

The check on the current CPU adds an extra level of indentation to
svm_deliver_avic_intr and conflates documentation on what happens
if the vCPU exits (of interest to svm_deliver_avic_intr) and migrates
(only of interest to avic_ring_doorbell, which calls get/put_cpu()).
Extract the wrmsr to a separate function and rewrite the
comment in svm_deliver_avic_intr().

Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2022-02-08 06:45:16 -05:00 committed by Paolo Bonzini
parent 0316dbb9a0
commit 0a5f784273
1 changed files with 20 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
arch/x86/kvm/svm/avic.c
View File

@ -269,6 +269,22 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
return 0;
}
static void avic_ring_doorbell(struct kvm_vcpu *vcpu)
{
/*
* Note, the vCPU could get migrated to a different pCPU at any point,
* which could result in signalling the wrong/previous pCPU. But if
* that happens the vCPU is guaranteed to do a VMRUN (after being
* migrated) and thus will process pending interrupts, i.e. a doorbell
* is not needed (and the spurious one is harmless).
*/
int cpu = READ_ONCE(vcpu->cpu);
if (cpu != get_cpu())
wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu));
put_cpu();
}
static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
u32 icrl, u32 icrh)
{
@ -669,19 +685,12 @@ int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
* automatically process AVIC interrupts at VMRUN.
*/
if (vcpu->mode == IN_GUEST_MODE) {
int cpu = READ_ONCE(vcpu->cpu);
/*
* Note, the vCPU could get migrated to a different pCPU at any
* point, which could result in signalling the wrong/previous
* pCPU. But if that happens the vCPU is guaranteed to do a
* VMRUN (after being migrated) and thus will process pending
* interrupts, i.e. a doorbell is not needed (and the spurious
* one is harmless).
* Signal the doorbell to tell hardware to inject the IRQ. If
* the vCPU exits the guest before the doorbell chimes, hardware
* will automatically process AVIC interrupts at the next VMRUN.
*/
if (cpu != get_cpu())
wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu));
put_cpu();
avic_ring_doorbell(vcpu);
} else {
/*
* Wake the vCPU if it was blocking. KVM will then detect the