From: Stefan Hajnoczi <stefanha@gmail.com>
To: Jordan Hargrave <jharg93@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] ahci: map memory via device's address space instead of address_space_memory
Date: Thu, 26 Feb 2015 14:45:04 +0000 [thread overview]
Message-ID: <20150226144504.GA23124@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <CAC1AzdfOy+3poMaH_4at-tfVy+fg4rpNN10zbQD4Oj28sZCuPg@mail.gmail.com>
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On Wed, Feb 25, 2015 at 11:13:09PM -0600, Jordan Hargrave wrote:
> Referencing this old thread:
> https://lists.nongnu.org/archive/html/qemu-devel/2014-07/msg00606.html
>
> I've run into an issue recently with testing q35 DMAR/intel iommu with ahci
> driver. My ahci driver writes the upper-32 bits (PORT_FIS_ADDR_HI) first
> then the lower 32-bits (PORT_FIS_ADDR).
>
> The contents of PORT_FIS_ADDR therefore are stale when the PORT_FIS_ADDR_HI
> write calls map_page(). DMAR translation fails at this point as the old
> stale address (from SEABIOS initialization) is not in the DMAR page table.
The AHCI device tries to map on register writes to both the base and
upper 32-bit registers. So it should work for a driver that writes
PORT_FIS_ADDR_HI before PORT_FIS_ADDR.
Does the iommu failure pose a problem?
Stefan
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next prev parent reply other threads:[~2015-02-26 14:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-26 5:13 [Qemu-devel] [PATCH] ahci: map memory via device's address space instead of address_space_memory Jordan Hargrave
2015-02-26 14:45 ` Stefan Hajnoczi [this message]
2015-02-26 21:31 ` Jordan Hargrave
2015-02-26 22:02 ` Paolo Bonzini
2015-03-09 22:42 ` John Snow
2015-02-26 22:31 ` John Snow
[not found] ` <CAC1AzdcoEUtiGyCSXSf0bniUvQZ9tTeX2Vc9KQUyBfQxFV+JFg@mail.gmail.com>
2015-03-02 16:37 ` John Snow
2015-03-12 17:41 ` John Snow
-- strict thread matches above, loose matches on Subject: below --
2014-07-03 8:26 Le Tan
2014-07-03 8:28 ` Michael S. Tsirkin
2014-07-03 8:47 ` Paolo Bonzini
2014-07-03 8:43 ` Jan Kiszka
2014-07-03 9:41 ` Paolo Bonzini
2014-07-03 10:11 ` Michael S. Tsirkin
2014-07-03 10:02 ` Michael S. Tsirkin
2014-07-03 16:45 ` Jan Kiszka
2014-07-03 20:30 ` Michael S. Tsirkin
2014-07-04 5:26 ` Jan Kiszka
2014-07-06 5:58 ` Michael S. Tsirkin
2014-07-07 8:23 ` Stefan Hajnoczi
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