[PATCH 4.9 21/27] KVM: arm/arm64: vgic-its: Preserve the revious read from the pending table

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 64afe6e9eb4841f35317da4393de21a047a883b3 upstream.

The current pending table parsing code assumes that we keep the
previous read of the pending bits, but keep that variable in
the current block, making sure it is discarded on each loop.

We end-up using whatever is on the stack. Who knows, it might
just be the right thing...

Fixes: 33d3bc9556a7d ("KVM: arm64: vgic-its: Read initial LPI pending table")
Cc: stable@xxxxxxxxxxxxxxx # 4.8
Reported-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 virt/kvm/arm/vgic/vgic-its.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -322,6 +322,7 @@ static int its_sync_lpi_pending_table(st
 	int ret = 0;
 	u32 *intids;
 	int nr_irqs, i;
+	u8 pendmask;
 
 	nr_irqs = vgic_copy_lpi_list(vcpu->kvm, &intids);
 	if (nr_irqs < 0)
@@ -329,7 +330,6 @@ static int its_sync_lpi_pending_table(st
 
 	for (i = 0; i < nr_irqs; i++) {
 		int byte_offset, bit_nr;
-		u8 pendmask;
 
 		byte_offset = intids[i] / BITS_PER_BYTE;
 		bit_nr = intids[i] % BITS_PER_BYTE;