[PATCH 4.0 067/105] MIPS: KVM: Do not sign extend on unsigned MMIO load

[Greg Kroah-Hartman]

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

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

From: Nicholas Mc Guire <hofrat@xxxxxxxxx>

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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/mips/kvm/emulate.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -2101,7 +2101,7 @@ enum emulation_result kvm_mips_complete_
 		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:


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