From: Avi Kivity <avi@redhat.com>
To: "Kumar, Venkat" <Venkat.Kumar@lsi.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: Virtio Queries
Date: Mon, 13 Apr 2009 16:26:42 +0300 [thread overview]
Message-ID: <49E33D92.20807@redhat.com> (raw)
In-Reply-To: <3D9CB4061D1EB3408D4A0B910433453C030298F073@inbmail01.lsi.com>
Kumar, Venkat wrote:
>> 2. If it is Guest physical address, how qemu converts it to its virtual address before processing the buffer?
>>
>>
>
> See the logic in cpu_physical_memory_rw() and cpu_physical_memory_map().
>
> ==> Thanks for the reply. Are these the functions which convert the Guest physical addresses to qemu Virtual addresses?
Yes.
> If yes, I did not find any routine calling these functions in the Virtio block IO flow. May be I missed it. Can you please point me to the code where Qemu's backend virtio driver is taking the SGE from the virt ring descriptor after it gets a notification from the guest and converting it to a qemu virtual address before calling "read or write" system calls.
>
It's in hw/virtio.c, see virtqueue_pop().
virtio-blk.c will issue the actual read or write (via
bdrv_aio_{read,write}v()).
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2009-04-13 13:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-09 15:43 Virtio Queries Kumar, Venkat
2009-04-13 11:07 ` Avi Kivity
2009-04-13 13:11 ` Kumar, Venkat
2009-04-13 13:26 ` Avi Kivity [this message]
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