From: Peter Maydell <peter.maydell@linaro.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Hervé Poussineau" <hpoussin@reactos.org>,
"QEMU Developers" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] virtio-pci: implement cfg capability
Date: Mon, 6 Jul 2015 11:04:24 +0100 [thread overview]
Message-ID: <CAFEAcA-EdJKgOHzKRr9e1XZu05FHRarZXC-gpAvUCnAL98FQXA@mail.gmail.com> (raw)
In-Reply-To: <20150706125811-mutt-send-email-mst@redhat.com>
On 6 July 2015 at 11:03, Michael S. Tsirkin <mst@redhat.com> wrote:
> On Mon, Jul 06, 2015 at 10:11:18AM +0100, Peter Maydell wrote:
>> But address_space_rw() is just the "memcpy bytes to the
>> target's memory" operation -- if you have a pile of bytes
>> then there are no endianness concerns. If you don't have
>> a pile of bytes then you need to know the structure of
>> the data you're DMAing around, and you should probably
>> have a loop doing things with the specify-the-width functions.
> Absolutely. But what if DMA happens to target another device
> and not memory? Device needs some endian-ness so it needs
> to be converted to that.
Yes, and address_space_rw() already deals with conversion to
that device's specified endianness.
-- PMM
next prev parent reply other threads:[~2015-07-06 10:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-02 13:00 [Qemu-devel] [PATCH] virtio-pci: implement cfg capability Michael S. Tsirkin
2015-07-02 18:48 ` Paolo Bonzini
2015-07-02 19:00 ` Michael S. Tsirkin
2015-07-02 19:02 ` Paolo Bonzini
2015-07-04 21:19 ` Michael S. Tsirkin
2015-07-06 7:46 ` Paolo Bonzini
2015-07-06 8:33 ` Michael S. Tsirkin
2015-07-06 8:46 ` Paolo Bonzini
2015-07-06 9:06 ` Michael S. Tsirkin
2015-07-06 9:11 ` Peter Maydell
2015-07-06 10:03 ` Michael S. Tsirkin
2015-07-06 10:04 ` Peter Maydell [this message]
2015-07-06 10:31 ` Michael S. Tsirkin
2015-07-06 11:50 ` Peter Maydell
2015-07-06 12:04 ` Paolo Bonzini
2015-07-06 12:15 ` Michael S. Tsirkin
2015-07-06 12:12 ` Michael S. Tsirkin
2015-07-06 12:23 ` Paolo Bonzini
2015-07-03 9:34 ` Gerd Hoffmann
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