Parts of the posted interrupt descriptor configure host behavior,
such as the notification vector and destination. Overwriting them
with zero as done during vCPU reset breaks posted interrupts.
KVM (re-)writes these fields on certain occasions and belatedly fixes
the situation in many cases. However, if you have a guest configured
with "idle=poll", for example, the fields might stay zero forever.
Do not reset the full descriptor in vmx_vcpu_reset(). Instead,
reset only the outstanding notifications and leave everything
else untouched.
Signed-off-by: Jan H. Schönherr <jschoenh@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e6c8ffa..2e008e4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5618,8 +5618,10 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu);
- if (kvm_vcpu_apicv_active(vcpu))
- memset(&vmx->pi_desc, 0, sizeof(struct pi_desc));
+ if (kvm_vcpu_apicv_active(vcpu)) {
+ pi_clear_on(&vmx->pi_desc);
+ memset(vmx->pi_desc.pir, 0, sizeof(vmx->pi_desc.pir));
+ }
if (vmx->vpid != 0)
vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid);
--
2.3.1.dirty
