All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: chrisw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	suresh.b.siddha-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	mingo-X9Un+BFzKDI@public.gmane.org
Subject: Re: [PATCH 2/2] iommu: dmar -- reserve mmio space used by IOMMU
Date: Wed, 6 Jun 2012 10:29:00 +0200	[thread overview]
Message-ID: <20120606082900.GF5991@gmail.com> (raw)
In-Reply-To: <1338971183.26785.33.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>


* David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> wrote:

> On Wed, 2012-06-06 at 10:16 +0200, Ingo Molnar wrote:
>
> > So basically the patch-set is fine as-is, we just want a 
> > sufficiently nasty sounding warning message about the BIOS 
> > bug,
> 
> No. The other change that's required is that the warning and 
> the workaround need to trigger even when IOMMU support isn't 
> built into the kernel. This BIOS bug can bite you even when 
> you aren't *using* the IOMMU.

Right, but that's the status quo and most of the time (distro 
kernels) the driver is available, right?

So for all practical purposes we get 99% of the warning power 
without going into chicken-and-egg problems like how do we 
determine that there's an IOMMU area there if there's no IOMMU 
aware code in the kernel, right?

Thanks,

	Ingo

WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>,
	iommu@lists.linux-foundation.org, mingo@elte.hu,
	linux-kernel@vger.kernel.org, chrisw@redhat.com,
	suresh.b.siddha@intel.com
Subject: Re: [PATCH 2/2] iommu: dmar -- reserve mmio space used by IOMMU
Date: Wed, 6 Jun 2012 10:29:00 +0200	[thread overview]
Message-ID: <20120606082900.GF5991@gmail.com> (raw)
In-Reply-To: <1338971183.26785.33.camel@shinybook.infradead.org>


* David Woodhouse <dwmw2@infradead.org> wrote:

> On Wed, 2012-06-06 at 10:16 +0200, Ingo Molnar wrote:
>
> > So basically the patch-set is fine as-is, we just want a 
> > sufficiently nasty sounding warning message about the BIOS 
> > bug,
> 
> No. The other change that's required is that the warning and 
> the workaround need to trigger even when IOMMU support isn't 
> built into the kernel. This BIOS bug can bite you even when 
> you aren't *using* the IOMMU.

Right, but that's the status quo and most of the time (distro 
kernels) the driver is available, right?

So for all practical purposes we get 99% of the warning power 
without going into chicken-and-egg problems like how do we 
determine that there's an IOMMU area there if there's no IOMMU 
aware code in the kernel, right?

Thanks,

	Ingo

  parent reply	other threads:[~2012-06-06  8:29 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-04 21:29 [PATCH 0/2]intel-iommu: reserve IOMMU register space Donald Dutile
2012-06-04 21:29 ` Donald Dutile
     [not found] ` <1338845342-12464-1-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 21:29   ` [PATCH 1/2] iommu: dmar: replace printks with appropriate pr_*() Donald Dutile
2012-06-04 21:29     ` Donald Dutile
     [not found]     ` <1338845342-12464-2-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 22:15       ` Joe Perches
2012-06-04 22:15         ` Joe Perches
2012-06-04 22:28         ` Don Dutile
2012-06-04 22:28           ` Don Dutile
2012-06-08 14:55     ` [tip:core/iommu] iommu/dmar: Replace printks with appropriate pr_* () tip-bot for Donald Dutile
2012-06-04 21:29   ` [PATCH 2/2] iommu: dmar -- reserve mmio space used by IOMMU Donald Dutile
2012-06-04 21:29     ` Donald Dutile
     [not found]     ` <1338845342-12464-3-git-send-email-ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 22:37       ` David Woodhouse
2012-06-04 22:37         ` David Woodhouse
     [not found]         ` <1338849430.10884.288.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-04 23:09           ` Don Dutile
2012-06-04 23:09             ` Don Dutile
     [not found]             ` <4FCD401D.9000304-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-06-04 23:23               ` David Woodhouse
2012-06-04 23:23                 ` David Woodhouse
     [not found]                 ` <1338852196.26785.10.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-04 23:52                   ` Don Dutile
2012-06-04 23:52                     ` Don Dutile
2012-06-06  8:16                   ` Ingo Molnar
2012-06-06  8:16                     ` Ingo Molnar
     [not found]                     ` <20120606081600.GB5991-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-06-06  8:26                       ` David Woodhouse
2012-06-06  8:26                         ` David Woodhouse
     [not found]                         ` <1338971183.26785.33.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-06  8:29                           ` Ingo Molnar [this message]
2012-06-06  8:29                             ` Ingo Molnar
     [not found]                             ` <20120606082900.GF5991-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-06-06  8:45                               ` David Woodhouse
2012-06-06  8:45                                 ` David Woodhouse
     [not found]                                 ` <1338972329.26785.34.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org>
2012-06-06 23:56                                   ` Chris Wright
2012-06-06 23:56                                     ` Chris Wright
2012-06-06 23:58                   ` Chris Wright
2012-06-06 23:58                     ` Chris Wright
2012-06-08 14:56     ` [tip:core/iommu] iommu/dmar: Reserve mmio space used by the IOMMU, if the BIOS forgets to tip-bot for Donald Dutile

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20120606082900.GF5991@gmail.com \
    --to=mingo-dgejt+ai2ygdnm+yrofe0a@public.gmane.org \
    --cc=chrisw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
    --cc=dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org \
    --cc=iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
    --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=mingo-X9Un+BFzKDI@public.gmane.org \
    --cc=suresh.b.siddha-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.