From: Anthony Liguori <aliguori@us.ibm.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
virtualization@lists.linux-foundation.org,
Stefan Hajnoczi <stefanha@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
KONRAD Frederic <fred.konrad@greensocs.com>
Subject: Re: [PATCH RFC] virtio-pci: new config layout: using memory BAR
Date: Wed, 05 Jun 2013 19:41:17 -0500 [thread overview]
Message-ID: <877gi8nk9e.fsf@codemonkey.ws> (raw)
In-Reply-To: <51AFC4A6.6070607@zytor.com>
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 06/05/2013 03:08 PM, Anthony Liguori wrote:
>>>
>>> Definitely an option. However, we want to be able to boot from native
>>> devices, too, so having an I/O BAR (which would not be used by the OS
>>> driver) should still at the very least be an option.
>>
>> What makes it so difficult to work with an MMIO bar for PCI-e?
>>
>> With legacy PCI, tracking allocation of MMIO vs. PIO is pretty straight
>> forward. Is there something special about PCI-e here?
>>
>
> It's not tracking allocation. It is that accessing memory above 1 MiB
> is incredibly painful in the BIOS environment, which basically means
> MMIO is inaccessible.
Oh, you mean in real mode.
SeaBIOS runs the virtio code in 32-bit mode with a flat memory layout.
There are loads of ASSERT32FLAT()s in the code to make sure of this.
Regards,
Anthony Liguori
>
> -hpa
>
>
> --
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next prev parent reply other threads:[~2013-06-06 0:41 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-28 16:03 [PATCH RFC] virtio-pci: new config layout: using memory BAR Michael S. Tsirkin
2013-05-28 17:15 ` Anthony Liguori
2013-05-28 17:15 ` Anthony Liguori
2013-05-28 17:32 ` Michael S. Tsirkin
2013-05-28 17:43 ` Paolo Bonzini
2013-05-29 2:02 ` Laszlo Ersek
2013-05-29 2:02 ` Laszlo Ersek
2013-05-29 4:33 ` Rusty Russell
2013-05-29 4:33 ` Rusty Russell
2013-05-29 7:27 ` Paolo Bonzini
2013-05-29 8:05 ` Michael S. Tsirkin
2013-05-29 10:07 ` Laszlo Ersek
2013-05-28 18:53 ` Anthony Liguori
2013-05-28 19:27 ` Michael S. Tsirkin
2013-05-29 4:31 ` Rusty Russell
2013-05-29 4:31 ` Rusty Russell
2013-05-29 8:24 ` Michael S. Tsirkin
2013-05-29 8:52 ` Paolo Bonzini
2013-05-29 9:00 ` Peter Maydell
2013-05-29 10:08 ` Michael S. Tsirkin
2013-05-29 10:53 ` Peter Maydell
2013-05-29 12:16 ` Michael S. Tsirkin
2013-05-29 12:28 ` Paolo Bonzini
2013-05-29 12:37 ` Michael S. Tsirkin
2013-05-29 12:52 ` Anthony Liguori
2013-05-29 12:52 ` Anthony Liguori
2013-05-29 13:24 ` Michael S. Tsirkin
2013-05-29 13:35 ` Peter Maydell
2013-05-29 13:35 ` Peter Maydell
2013-05-29 13:41 ` Paolo Bonzini
2013-05-29 14:02 ` Michael S. Tsirkin
2013-05-29 14:18 ` Anthony Liguori
2013-05-29 14:18 ` Anthony Liguori
2013-05-30 7:43 ` Michael S. Tsirkin
2013-05-29 14:16 ` Anthony Liguori
2013-05-29 14:16 ` Anthony Liguori
2013-05-29 14:30 ` Michael S. Tsirkin
2013-05-29 14:32 ` Paolo Bonzini
2013-05-29 14:52 ` Michael S. Tsirkin
2013-05-29 14:55 ` Anthony Liguori
2013-05-29 16:12 ` Michael S. Tsirkin
2013-05-29 18:16 ` Michael S. Tsirkin
2013-05-29 14:55 ` Anthony Liguori
2013-05-30 3:58 ` Rusty Russell
2013-05-30 3:58 ` Rusty Russell
2013-05-30 5:55 ` Michael S. Tsirkin
2013-05-30 7:55 ` Michael S. Tsirkin
2013-06-03 0:17 ` Rusty Russell
2013-05-30 13:53 ` Anthony Liguori
2013-05-30 13:53 ` Anthony Liguori
2013-05-30 14:01 ` Michael S. Tsirkin
2013-06-03 0:26 ` Rusty Russell
2013-06-03 10:11 ` Michael S. Tsirkin
2013-06-04 5:31 ` Rusty Russell
2013-06-04 6:42 ` Michael S. Tsirkin
2013-06-05 7:19 ` Rusty Russell
2013-06-05 10:22 ` Michael S. Tsirkin
2013-06-05 12:59 ` Anthony Liguori
2013-06-05 14:09 ` Michael S. Tsirkin
2013-06-05 15:08 ` Anthony Liguori
2013-06-05 15:19 ` Michael S. Tsirkin
2013-06-05 15:46 ` Anthony Liguori
2013-06-05 15:46 ` Anthony Liguori
2013-06-05 16:20 ` Michael S. Tsirkin
2013-06-05 18:57 ` Anthony Liguori
2013-06-05 19:43 ` Michael S. Tsirkin
2013-06-05 19:52 ` Michael S. Tsirkin
2013-06-05 20:45 ` Anthony Liguori
2013-06-05 21:15 ` H. Peter Anvin
2013-06-05 21:15 ` Michael S. Tsirkin
2013-06-05 20:42 ` Anthony Liguori
2013-06-05 21:14 ` Michael S. Tsirkin
2013-06-05 21:53 ` Anthony Liguori
2013-06-05 22:19 ` Benjamin Herrenschmidt
2013-06-05 22:53 ` Anthony Liguori
2013-06-05 23:27 ` Benjamin Herrenschmidt
2013-06-05 21:53 ` Anthony Liguori
2013-06-05 19:54 ` Michael S. Tsirkin
2013-06-06 3:42 ` Rusty Russell
2013-06-06 14:59 ` Anthony Liguori
2013-06-07 1:58 ` Rusty Russell
2013-06-07 8:25 ` Peter Maydell
2013-06-05 21:10 ` H. Peter Anvin
2013-06-05 21:17 ` Michael S. Tsirkin
2013-06-05 21:50 ` Anthony Liguori
2013-06-05 21:55 ` H. Peter Anvin
2013-06-05 22:08 ` Anthony Liguori
2013-06-05 23:07 ` H. Peter Anvin
2013-06-06 0:41 ` Anthony Liguori [this message]
2013-06-06 6:34 ` Gleb Natapov
2013-06-06 13:53 ` H. Peter Anvin
2013-06-06 15:02 ` Anthony Liguori
2013-06-07 11:30 ` Gleb Natapov
2013-06-11 7:10 ` Michael S. Tsirkin
2013-06-11 7:53 ` Gleb Natapov
2013-06-11 8:02 ` Michael S. Tsirkin
2013-06-11 8:03 ` Gleb Natapov
2013-06-11 8:19 ` Michael S. Tsirkin
2013-06-11 8:22 ` Gleb Natapov
2013-06-11 8:30 ` Michael S. Tsirkin
2013-06-11 8:32 ` Gleb Natapov
2013-06-11 8:04 ` Michael S. Tsirkin
2013-06-06 15:02 ` Anthony Liguori
2013-06-06 15:06 ` Gerd Hoffmann
2013-06-06 15:10 ` Gleb Natapov
2013-06-06 15:19 ` H. Peter Anvin
2013-06-06 15:22 ` Gerd Hoffmann
2013-07-08 4:25 ` Kevin O'Connor
2013-06-06 8:02 ` Michael S. Tsirkin
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