On Thu, 30 Jun 2022 17:12:20 +0100,
Schspa Shi <schspa@xxxxxxxxx> wrote:
>
> If the len is 8 bytes, we can't get the correct sign extend for
> be system.
I'm afraid you'll have to give me a bit more details.
>
> Fix the mask type len and the comparison of length.
>
> Signed-off-by: Schspa Shi <schspa@xxxxxxxxx>
> ---
> arch/arm64/kvm/mmio.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c
> index 3dd38a151d2a6..0692f8b18f35c 100644
> --- a/arch/arm64/kvm/mmio.c
> +++ b/arch/arm64/kvm/mmio.c
> @@ -81,8 +81,8 @@ unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
> int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
> {
> unsigned long data;
> + unsigned long mask;
> unsigned int len;
> - int mask;
>
> /* Detect an already handled MMIO return */
> if (unlikely(!vcpu->mmio_needed))
> @@ -97,7 +97,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
> data = kvm_mmio_read_buf(run->mmio.data, len);
>
> if (kvm_vcpu_dabt_issext(vcpu) &&
> - len < sizeof(unsigned long)) {
> + len <= sizeof(unsigned long)) {
If you're reading an 8 byte quantity, what is there to sign-extend?
Sign extension only makes sense if what you're reading is *smaller*
than the size of the register you are targeting.
I must be missing something. And how is that related to running BE? BE
in the host? The guest?
Please convince me.
M.
--
Without deviation from the norm, progress is not possible.
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