From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/8] virtio_get_byteswap: function for endian-ambivalent targets using virtio.
Date: Mon, 12 Aug 2013 19:56:39 +1000 [thread overview]
Message-ID: <1376301399.32100.164.camel@pasglop> (raw)
In-Reply-To: <CAFEAcA_=4vb07jVs=bEZJJwkTVy3KDssxqsawKoyKAswmEBafg@mail.gmail.com>
On Mon, 2013-08-12 at 10:52 +0100, Peter Maydell wrote:
> On 12 August 2013 10:50, Benjamin Herrenschmidt
> <benh@kernel.crashing.org> wrote:
> > I must be confused ... you mentioned in a previous discussion around
> > endianness that on some ARM cores at least, when changing the OS
> > endianness, you had to configure a different lane swapping in the bridge
> > to the the IO devices (AXI ?)
>
> No, that's just the implementation -- the bit in the control
> register is effectively controlling whether there is byte lane
> swapping in the part of the CPU which is the data path between
> it and its bus to the outside world.
I find it amazing that an OS can touch that without hitting the
hypervisor :-) Anyway, ok, we do need to poll from virtio then, but we
probably need to cache as well, no ?
When do you sample it in qemu ?
Cheers,
Ben.
next prev parent reply other threads:[~2013-08-12 9:56 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-12 7:59 [Qemu-devel] [PATCH 0/8] virtio for endian curious guests Take #2 Rusty Russell
2013-08-12 7:59 ` [Qemu-devel] [PATCH 1/8] virtio_get_byteswap: function for endian-ambivalent targets using virtio Rusty Russell
2013-08-12 9:28 ` Benjamin Herrenschmidt
2013-08-12 9:39 ` Peter Maydell
2013-08-12 9:43 ` Benjamin Herrenschmidt
2013-08-12 9:45 ` Peter Maydell
2013-08-12 9:50 ` Benjamin Herrenschmidt
2013-08-12 9:52 ` Peter Maydell
2013-08-12 9:56 ` Benjamin Herrenschmidt [this message]
2013-08-12 10:36 ` Peter Maydell
2013-08-12 12:56 ` Anthony Liguori
2013-08-13 4:20 ` Rusty Russell
2013-08-13 5:30 ` Benjamin Herrenschmidt
2013-08-14 0:03 ` Rusty Russell
2013-09-06 2:27 ` Rusty Russell
2013-08-12 7:59 ` [Qemu-devel] [PATCH 2/8] target-ppc: ppc64 target's virtio can be either endian Rusty Russell
2013-08-12 7:59 ` [Qemu-devel] [PATCH 3/8] virtio: allow byte swapping for vring and config access Rusty Russell
2013-09-09 12:44 ` [Qemu-devel] [PATCH] hw/9pfs/virtio_9p_device: use virtio wrappers to access headers Greg Kurz
2013-09-10 5:21 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2014-02-18 12:38 [Qemu-devel] [PATCH 0/8] virtio endian-ambivalent target fixes (rebased) Greg Kurz
2014-02-18 12:38 ` [Qemu-devel] [PATCH 1/8] virtio_get_byteswap: function for endian-ambivalent targets using virtio Greg Kurz
2014-02-18 14:48 ` Alexander Graf
2014-02-18 15:03 ` Michael S. Tsirkin
2014-02-18 15:02 ` Alexander Graf
2014-02-18 15:11 ` Michael S. Tsirkin
2014-02-18 15:07 ` Alexander Graf
2014-02-18 15:04 ` Michael S. Tsirkin
2014-02-18 15:12 ` Cornelia Huck
2014-02-18 15:45 ` Cornelia Huck
2014-02-18 16:02 ` Alexander Graf
2014-02-18 16:17 ` Cornelia Huck
2014-02-18 16:21 ` Alexander Graf
2014-02-20 23:26 ` Rusty Russell
2014-02-18 23:02 ` Andreas Färber
2014-02-18 19:25 ` Andreas Färber
2014-02-19 10:06 ` Greg Kurz
2014-02-20 23:19 ` Rusty Russell
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