[v4.14,backport] KVM: arm/arm64: vgic-its: Preserve the revious read from the pending table

Message ID 20171214210424.25740-4-christoffer.dall@linaro.org
State New
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  • [v4.14,backport] KVM: arm/arm64: vgic-its: Preserve the revious read from the pending table
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Commit Message

Christoffer Dall Dec. 14, 2017, 9:04 p.m.
From: Marc Zyngier <marc.zyngier@arm.com>


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@vger.kernel.org> # 4.8
Reported-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

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

-- 
2.14.2

Comments

Greg KH Dec. 14, 2017, 9:16 p.m. | #1
On Thu, Dec 14, 2017 at 10:04:24PM +0100, Christoffer Dall wrote:
> From: Marc Zyngier <marc.zyngier@arm.com>

> 

> 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@vger.kernel.org> # 4.8

> Reported-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

> ---

>  virt/kvm/arm/vgic/vgic-its.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)


Now applied, thanks.

greg k-h

Patch

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 547f12dc4d54..d5a8bfe78bc4 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -393,6 +393,7 @@  static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
 	int ret = 0;
 	u32 *intids;
 	int nr_irqs, i;
+	u8 pendmask;
 
 	nr_irqs = vgic_copy_lpi_list(vcpu, &intids);
 	if (nr_irqs < 0)
@@ -400,7 +401,6 @@  static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
 
 	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;