ARM: KVM: Fix length of mmio access

Instead of hardcoding the maximum MMIO access to be 4 bytes,
compare it to sizeof(unsigned long), which will do the
right thing on both 32 and 64bit systems.

Same thing for sign extention.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
index 02ca76555bd4..72a12f2171b2 100644
--- a/arch/arm/kvm/mmio.c
+++ b/arch/arm/kvm/mmio.c
@@ -39,10 +39,10 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
         if (!run->mmio.is_write) {
                 dest = vcpu_reg(vcpu, vcpu->arch.mmio_decode.rt);
-                memset(dest, 0, sizeof(int));
+                *dest = 0;
 
                 len = run->mmio.len;
-                if (len > 4)
+                if (len > sizeof(unsigned long))
                         return -EINVAL;
 
                 memcpy(dest, run->mmio.data, len);
@@ -50,7 +50,8 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
                 trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
                                 *((u64 *)run->mmio.data));
 
-                if (vcpu->arch.mmio_decode.sign_extend && len < 4) {
+                if (vcpu->arch.mmio_decode.sign_extend &&
+                    len < sizeof(unsigned long)) {
                         mask = 1U << ((len * 8) - 1);
                         *dest = (*dest ^ mask) - mask;
                 }