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Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs |
Date: |
Mon, 27 Jan 2014 23:49:34 +0000 |
On 27 January 2014 23:34, Benjamin Herrenschmidt
<address@hidden> wrote:
> On Wed, 2014-01-22 at 20:02 +0000, Peter Maydell wrote:
>>
>> Defining it as being always guest-order would mean that
>> userspace had to continually look at the guest CPU
>> endianness bit, which is annoying and awkward.
>>
>> Defining it as always host-endian order is the most
>> reasonable option available. It also happens to work
>> for the current QEMU code, which is nice.
>
> No.
>
> Having a byte array coming in that represents what the CPU does in its
> current byte order means you do *NOT* need to query the endianness of
> the guest CPU from userspace.
Er, what? If we make the array be guest's current order
then by definition userspace has to look at the guest's
current endianness. I agree that would be bad. Either
of the two current proposals (host kernel order; guest
CPU's native/natural/default-byte-order) avoid it, though.
-- PMM
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, (continued)
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, Victor Kamensky, 2014/01/23
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, Christoffer Dall, 2014/01/23
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, Victor Kamensky, 2014/01/23
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Christoffer Dall, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, Victor Kamensky, 2014/01/23
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs,
Peter Maydell <=
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Christoffer Dall, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Christoffer Dall, 2014/01/28
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Benjamin Herrenschmidt, 2014/01/27
- Re: [Qemu-devel] [Qemu-ppc] KVM and variable-endianness guest CPUs, Avi Kivity, 2014/01/28
- Re: [Qemu-devel] KVM and variable-endianness guest CPUs, Avi Kivity, 2014/01/28