On 07/05/15 13:47, Nicholas Mc Guire wrote: > 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> Looks good to me. I wrote an MMIO test to reproduce the issue, and this fixes it. Reviewed-by: James Hogan <james.hogan@xxxxxxxxxx> Tested-by: James Hogan <james.hogan@xxxxxxxxxx> It looks suitable for stable too (3.10+). Cheers James > --- > > Thanks to James Hogan <james.hogan@xxxxxxxxxx> for the explaination of > mmio_needed (there is not really any helpful comment in the code on this) > in this case (mmio_needed!=2) it should be unsigned. > > Patch was only compile tested msp71xx_defconfig + CONFIG_KVM=m > > Patch is against 4.1-rc2 (localversion-next is -next-20150506) > > arch/mips/kvm/emulate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c > index 6230f37..2f0fc60 100644 > --- a/arch/mips/kvm/emulate.c > +++ b/arch/mips/kvm/emulate.c > @@ -2415,7 +2415,7 @@ enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu, > 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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