arm/arm64: KVM: Fix unaligned access bug on gicv2 access

We were using an atomic bitop on the vgic_v2.vgic_elrsr field which was
not aligned to the natural size on 64-bit platforms.  This bug showed up
after QEMU correctly identifies the pl011 line as being level-triggered,
and not edge-triggered.

These data structures are protected by a spinlock so simply use a
non-atomic version of the accessor instead.

Tested-by: Joel Schopp <joel.schopp@amd.com>
Reported-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

diff --git a/virt/kvm/arm/vgic-v2.c b/virt/kvm/arm/vgic-v2.c
index 01124ef..416baed 100644 (file)
--- a/virt/kvm/arm/vgic-v2.c
+++ b/virt/kvm/arm/vgic-v2.c
@@ -71,7 +71,7 @@ static void vgic_v2_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr,
                                  struct vgic_lr lr_desc)
 {
        if (!(lr_desc.state & LR_STATE_MASK))
-               set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr);
+               __set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr);
 }
 
 static u64 vgic_v2_get_elrsr(const struct kvm_vcpu *vcpu)