From 0624fca9512d08cbd9b5d098d904c840d3432404 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 1 Oct 2018 16:07:18 +0200
Subject: [PATCH] kvm/x86: return meaningful value from KVM_SIGNAL_MSI
If kvm_apic_map_get_dest_lapic() finds a disabled LAPIC,
it will return with bitmap==0 and (*r == -1) will be returned to
userspace.
QEMU may then record "KVM: injection failed, MSI lost
(Operation not permitted)" in its log, which is quite puzzling.
Reported-by: Peng Hao <penghao122@sina.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/lapic.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 91ffb63397f52..452eed992aead 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -960,14 +960,14 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
map = rcu_dereference(kvm->arch.apic_map);
ret = kvm_apic_map_get_dest_lapic(kvm, &src, irq, map, &dst, &bitmap);
- if (ret)
+ if (ret) {
+ *r = 0;
for_each_set_bit(i, &bitmap, 16) {
if (!dst[i])
continue;
- if (*r < 0)
- *r = 0;
*r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
}
+ }
rcu_read_unlock();
return ret;
--
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