From: "H. Peter Anvin" <hpa@zytor.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
"rusty@rustcorp.com.au" <rusty@rustcorp.com.au>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>,
"Xie, Huawei" <huawei.xie@intel.com>,
Laszlo Ersek <lersek@redhat.com>
Subject: Re: [Qemu-devel] Would virtio support 64 bit address for vring virtqueue?
Date: Wed, 28 Aug 2013 14:02:13 -0700 [thread overview]
Message-ID: <521E6555.9010400@zytor.com> (raw)
In-Reply-To: <CA+aC4kvDUy4vDptEWesV_d0NmouZLHgWyUtPSFkUoE=Y43JPdw@mail.gmail.com>
On 08/28/2013 10:35 AM, Anthony Liguori wrote:
> Yes, it was originally designed with the 16TB limit in mind.
>
> PCI doesn't support 64-bit PIO operations so it would have required a
> high/low register and additional magic.
>
s/PCI/x86/
"Additional magic" is needed only if atomic changes are necessary, but
in this case this is stuff that is set up during early configuration and
so isn't an issue. The "additional magic" needed in that case is latch
logic - the write to the low part doesn't actually take effect until the
high part is written.
-hpa
next prev parent reply other threads:[~2013-08-28 22:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-28 3:18 [Qemu-devel] Would virtio support 64 bit address for vring virtqueue? Xie, Huawei
2013-08-28 8:07 ` Stefan Hajnoczi
2013-08-28 9:22 ` Xie, Huawei
2013-08-28 11:45 ` Laszlo Ersek
2013-08-28 12:20 ` Christian Borntraeger
2013-08-28 15:30 ` Xie, Huawei
2013-08-28 17:35 ` Anthony Liguori
2013-08-28 21:02 ` H. Peter Anvin [this message]
2013-08-28 21:28 ` Anthony Liguori
2013-08-28 21:38 ` Richard Henderson
2013-08-28 10:16 ` Xie, Huawei
2013-09-04 6:52 ` Rusty Russell
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