From: Joerg Roedel <jroedel@suse.de>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Joerg Roedel <joro@8bytes.org>,
iommu@lists.linux-foundation.org, zhen-hual@hp.com,
bhe@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] iommu/vt-d: Don't consider copied context entries as present
Date: Thu, 11 Jun 2015 16:25:54 +0200 [thread overview]
Message-ID: <20150611142554.GG16345@suse.de> (raw)
In-Reply-To: <1434031622.3907.40.camel@infradead.org>
On Thu, Jun 11, 2015 at 03:07:02PM +0100, David Woodhouse wrote:
> On Thu, 2015-06-11 at 15:47 +0200, Joerg Roedel wrote:
> > From: Joerg Roedel <jroedel@suse.de>
> >
> > Hide the copied context entries from the IOMMU driver by
> > considering them as non-present. This is implemented by
> > setting the first AVL bit (bit 67) in the context entry to
> > one. If this bit is set, the context_present() function
> > returns false.
> >
> > Signed-off-by: Joerg Roedel <jroedel@suse.de>
>
> In the extended context entry, bit 67 is the PGE bit. There are no bits
> which are available to software, to my knowledge.
Okay, reading the VT-d spec again, the extended context-entry table seem
to exist in parallel to the current context-entry table, right? So this
patch should still work, even with extended entries present.
If that's true, then we only need to consider the kdump case while
setting up the extended context table entry (which means don't trust any
content that is already there).
Joerg
next prev parent reply other threads:[~2015-06-11 14:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 13:47 [PATCH 0/4] More cleanups and fixes for Intel VT-d Joerg Roedel
2015-06-11 13:47 ` [PATCH 1/4] iommu/vt-d: Remove iommu_attach_domain_with_id() Joerg Roedel
2015-06-11 13:47 ` [PATCH 2/4] iommu/vt-d: Don't consider copied context entries as present Joerg Roedel
2015-06-11 14:07 ` David Woodhouse
2015-06-11 14:12 ` Joerg Roedel
2015-06-11 14:19 ` David Woodhouse
2015-06-11 14:25 ` Joerg Roedel [this message]
2015-06-11 14:44 ` David Woodhouse
2015-06-11 15:12 ` David Woodhouse
2015-06-11 14:51 ` Joerg Roedel
2015-06-11 13:47 ` [PATCH 3/4] iommu/vt-d: Remove unmap_device_dma() Joerg Roedel
2015-06-11 13:47 ` [PATCH 4/4] iommu/vt-d: Make sure si_domain is allocated for kdump kernel Joerg Roedel
2015-06-11 15:54 ` [PATCH 0/4] More cleanups and fixes for Intel VT-d David Woodhouse
2015-06-12 7:31 ` Joerg Roedel
2015-06-12 20:29 ` Joerg Roedel
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