From: David Woodhouse <dwmw@xxxxxxxxxxxx>
The kvm_xen_inject_vcpu_vector() function has a comment saying "the fast
version will always work for physical unicast", justifying its use of
kvm_irq_delivery_to_apic_fast() and the WARN_ON_ONCE() when that fails.
In fact that assumption isn't true if X2APIC isn't in use by the guest
and there is (8-bit x)APIC ID aliasing. A single "unicast" destination
APIC ID *may* then be delivered to multiple vCPUs. Remove the warning,
and in fact it might as well just call kvm_irq_delivery_to_apic().
Reported-by: Michal Luczaj <mhal@xxxxxxx>
Fixes: fde0451be8fb3 ("KVM: x86/xen: Support per-vCPU event channel upcall via local APIC")
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/kvm/xen.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 847d9e75df6d..e6c7353e5315 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -10,7 +10,7 @@
#include "x86.h"
#include "xen.h"
#include "hyperv.h"
-#include "lapic.h"
+#include "irq.h"
#include <linux/eventfd.h>
#include <linux/kvm_host.h>
@@ -571,7 +571,6 @@ void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
{
struct kvm_lapic_irq irq = { };
- int r;
irq.dest_id = v->vcpu_id;
irq.vector = v->arch.xen.upcall_vector;
@@ -580,8 +579,7 @@ void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
irq.delivery_mode = APIC_DM_FIXED;
irq.level = 1;
- /* The fast version will always work for physical unicast */
- WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL));
+ kvm_irq_delivery_to_apic(v->kvm, NULL, &irq, NULL);
}
/*
--
2.43.0
