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* [PATCH] KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap
@ 2019-11-20 12:12 Nitesh Narayan Lal
  2019-11-20 12:33 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Nitesh Narayan Lal @ 2019-11-20 12:12 UTC (permalink / raw)
  To: kvm, linux-kernel, pbonzini, mtosatti, rkrcmar, vkuznets,
	sean.j.christopherson, wanpengli, jmattson, joro

Not zeroing the bitmap used for identifying the destination vCPUs for an
IOAPIC scan request in fixed delivery mode could lead to waking up unwanted
vCPUs. This patch zeroes the vCPU bitmap before passing it to
kvm_bitmap_or_dest_vcpus(), which is responsible for setting the bitmap
with the bits corresponding to the destination vCPUs.

Fixes: 7ee30bc132c6("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
Signed-off-by: Nitesh Narayan Lal <>
 arch/x86/kvm/ioapic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index ce30ef23c86b..9fd2dd89a1c5 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -332,6 +332,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 			irq.delivery_mode = e->fields.delivery_mode << 8;
 			irq.dest_id = e->fields.dest_id;
 			irq.dest_mode = e->fields.dest_mode;
+			bitmap_zero(&vcpu_bitmap, 16);
 			kvm_bitmap_or_dest_vcpus(ioapic->kvm, &irq,
 			if (old_dest_mode != e->fields.dest_mode ||

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-11-20 12:12 [PATCH] KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap Nitesh Narayan Lal
2019-11-20 12:33 ` Paolo Bonzini

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