On Tue, Feb 11, 2014 at 09:41:33PM -0800, Victor Kamensky wrote:
> In case of status register E bit is not set (LE mode) and host runs in
> BE mode we need byteswap data, so read/write is emulated correctly.
>
> Signed-off-by: Victor Kamensky <victor.kamensky@xxxxxxxxxx>
> ---
> arch/arm/include/asm/kvm_emulate.h | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
> index 0fa90c9..69b7469 100644
> --- a/arch/arm/include/asm/kvm_emulate.h
> +++ b/arch/arm/include/asm/kvm_emulate.h
> @@ -185,9 +185,16 @@ static inline unsigned long vcpu_data_guest_to_host(struct kvm_vcpu *vcpu,
> default:
> return be32_to_cpu(data);
> }
> + } else {
> + switch (len) {
> + case 1:
> + return data & 0xff;
> + case 2:
> + return le16_to_cpu(data & 0xffff);
> + default:
> + return le32_to_cpu(data);
> + }
> }
> -
> - return data; /* Leave LE untouched */
> }
>
> static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
> @@ -203,9 +210,16 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
> default:
> return cpu_to_be32(data);
> }
> + } else {
> + switch (len) {
> + case 1:
> + return data & 0xff;
> + case 2:
> + return cpu_to_le16(data & 0xffff);
> + default:
> + return cpu_to_le32(data);
> + }
> }
> -
> - return data; /* Leave LE untouched */
> }
>
> #endif /* __ARM_KVM_EMULATE_H__ */
> --
> 1.8.1.4
>
Somehow in my head the way I think about this is
if (guest_be != host_be) {
return swab(data);
}
but it's probably not more clear in terms of the actual code...
Anyway, given that the ABI clarification text gets merged:
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
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