diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2024-02-27 11:49:17 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-03-04 16:22:37 -0800 |
| commit | 66e3cf729b1ea017cad643415ade319556862b68 (patch) | |
| tree | 197f09d57570987c0ee36e2f2e6e372730d1f5e8 /arch | |
| parent | 8e62bf2bfa46367e14d0ffdcde5aada08759497c (diff) | |
KVM: x86/xen: remove WARN_ON_ONCE() with false positives in evtchn delivery
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@rbox.co>
Fixes: fde0451be8fb3 ("KVM: x86/xen: Support per-vCPU event channel upcall via local APIC")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20240227115648.3104-4-dwmw2@infradead.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/xen.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 5c24c92588cf..54c4ced96b69 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> @@ -570,7 +570,6 @@ 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; @@ -579,8 +578,7 @@ 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); } /* |