lkml.org 
[lkml]   [2022]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RESEND 08/30] KVM: x86: lapic: don't touch irr_pending in kvm_apic_update_apicv when inhibiting it
Date
kvm_apic_update_apicv is called when AVIC is still active, thus IRR bits
can be set by the CPU after it is called, and don't cause the irr_pending
to be set to true.

Also logic in avic_kick_target_vcpu doesn't expect a race with this
function so to make it simple, just keep irr_pending set to true and
let the next interrupt injection to the guest clear it.


Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/lapic.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0da7d0960fcb5..dd4e2888c244b 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2307,7 +2307,12 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
apic->irr_pending = true;
apic->isr_count = 1;
} else {
- apic->irr_pending = (apic_search_irr(apic) != -1);
+ /*
+ * Don't clear irr_pending, searching the IRR can race with
+ * updates from the CPU as APICv is still active from hardware's
+ * perspective. The flag will be cleared as appropriate when
+ * KVM injects the interrupt.
+ */
apic->isr_count = count_vectors(apic->regs + APIC_ISR);
}
}
--
2.26.3
\
 
 \ /
  Last update: 2022-02-07 17:11    [W:0.173 / U:0.612 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site