From: Peter Maydell <peter.maydell@linaro.org>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Alex Williamson <alex.williamson@redhat.com>,
qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] [PATCH RFC] vga: flag vga ram for notifiers
Date: Thu, 31 Mar 2011 22:32:11 +0100 [thread overview]
Message-ID: <AANLkTi=x3R29QJzxc9gNbsUKHzY-zgx+P2foWCkdh0k=@mail.gmail.com> (raw)
In-Reply-To: <4D94E2A7.80700@codemonkey.ws>
On 31 March 2011 21:23, Anthony Liguori <anthony@codemonkey.ws> wrote:
> On 03/31/2011 03:12 PM, Peter Maydell wrote:
>> Well, obviously you need to be able to revoke the permission
>> to use the fastpath pointer to the underlying memory. But you
>> need to be able to do that anyhow, to cover cases where (eg) the
>> guest has just written to some register that remaps the bottom
>> part of the address space so it's ROM rather than RAM, or whatever.
>> It's just a feature your optimisation needs to have. Equally, you
>> don't remap unless you have to, but if the mapping's changed then
>> it's changed...
>
> Right, the trouble now is that there's no way to distinguish between mapping
> where 1) we don't care about them in virtio and 2) they change frequently.
Aha. Thanks for the explanation.
> Maybe the right approach here is to just use a virtio specific API and
> register RAM as register_virtio_dma_area().
That seems like a clearer API, yes. I think it makes it much more
obvious what it's trying to achieve.
-- PMM
next prev parent reply other threads:[~2011-03-31 21:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-31 17:43 [Qemu-devel] [PATCH RFC] vga: flag vga ram for notifiers Michael S. Tsirkin
2011-03-31 18:33 ` Anthony Liguori
2011-03-31 18:49 ` Michael S. Tsirkin
2011-03-31 19:01 ` Anthony Liguori
2011-03-31 19:07 ` Michael S. Tsirkin
2011-03-31 19:26 ` Anthony Liguori
2011-03-31 20:03 ` Michael S. Tsirkin
2011-03-31 20:21 ` Anthony Liguori
2011-03-31 19:17 ` Alex Williamson
2011-03-31 19:18 ` Peter Maydell
2011-03-31 19:29 ` Anthony Liguori
2011-03-31 20:12 ` Peter Maydell
2011-03-31 20:23 ` Anthony Liguori
2011-03-31 21:32 ` Peter Maydell [this message]
2011-03-31 21:38 ` Michael S. Tsirkin
2011-03-31 21:49 ` Anthony Liguori
2011-03-31 23:42 ` Michael S. Tsirkin
2011-04-01 0:44 ` Anthony Liguori
2011-04-01 1:07 ` Michael S. Tsirkin
2011-04-01 7:12 ` Peter Maydell
2011-04-01 11:21 ` Michael S. Tsirkin
2011-03-31 21:26 ` Michael S. Tsirkin
2011-03-31 21:32 ` Anthony Liguori
2011-03-31 21:37 ` Michael S. Tsirkin
2011-03-31 21:48 ` Anthony Liguori
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