From: "Pasi Kärkkäinen" <pasik@iki.fi>
To: Igor Druzhinin <igor.druzhinin@citrix.com>
Cc: kevin.tian@intel.com, sstabellini@kernel.org,
wei.liu2@citrix.com, konrad.wilk@oracle.com,
George.Dunlap@eu.citrix.com, andrew.cooper3@citrix.com,
julien.grall@arm.com, jbeulich@suse.com,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH] VT-d/DMAR: accept DRHD with non-discoverable PCI devices
Date: Thu, 21 Mar 2019 18:55:30 +0200 [thread overview]
Message-ID: <20190321165530.GI32745@reaktio.net> (raw)
In-Reply-To: <1553113323-14664-1-git-send-email-igor.druzhinin@citrix.com>
On Wed, Mar 20, 2019 at 08:22:03PM +0000, Igor Druzhinin wrote:
> Since commit dcf41790 ("x86/mmcfg/drhd: Move acpi_mmcfg_init() call
> before calling acpi_parse_dmar()") PCI segment 0 is now known early
> which made the sanity check on DRHD definition structure to work.
> This, in turn, caused a regression on some machines (in particular,
> HP PowerEdge R740 with I/O AT DMA disabled) where IOMMU was explicitly
^^^^
That's probably a typo.. sounds like it should say "Dell PowerEdge R740", not HP..
-- Pasi
> disabled due to some internal PCI devices being non-discoverable but
> present in DMAR.
>
> While this is indeed a BIOS mistake it seems to be not that critical
> to disable the whole IOMMU. Instead, extend the scope of
> "workaround_bios_bug" option and make it enabled by default. This is
> consistent with our documentation and actually what a user might expect
> from an option with that name. It also doesn't seem safe to simply ignore
> DRHD without initialization so remove this case. But leave the original
> DMAR check in place to still allow error reporting.
>
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
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prev parent reply other threads:[~2019-03-21 16:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 20:22 [PATCH] VT-d/DMAR: accept DRHD with non-discoverable PCI devices Igor Druzhinin
2019-03-21 13:17 ` Andrew Cooper
2019-03-21 13:50 ` Juergen Gross
2019-03-21 18:04 ` Igor Druzhinin
2019-03-21 16:55 ` Pasi Kärkkäinen [this message]
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