[patch added to the 3.12 stable tree] MIPS: KVM: Do not sign extend on unsigned MMIO load

From: Jiri Slaby
Date: Wed Jun 10 2015 - 09:24:13 EST


From: Nicholas Mc Guire <hofrat@xxxxxxxxx>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit ed9244e6c534612d2b5ae47feab2f55a0d4b4ced upstream.

Fix possible unintended sign extension in unsigned MMIO loads by casting
to uint16_t in the case of mmio_needed != 2.

Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
Reviewed-by: James Hogan <james.hogan@xxxxxxxxxx>
Tested-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/9985/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
arch/mips/kvm/kvm_mips_emul.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index e75ef8219caf..c76f297b7149 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -1626,7 +1626,7 @@ kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu, struct kvm_run *run)
if (vcpu->mmio_needed == 2)
*gpr = *(int16_t *) run->mmio.data;
else
- *gpr = *(int16_t *) run->mmio.data;
+ *gpr = *(uint16_t *)run->mmio.data;

break;
case 1:
--
2.4.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/