WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] RE: [Xen-changelog] [xen-unstable]vt-d: Fixpanic in msi_msg_

To: Dexuan Cui <dexuan.cui@xxxxxxxxx>
Subject: [Xen-devel] RE: [Xen-changelog] [xen-unstable]vt-d: Fixpanic in msi_msg_read_remap_rte with acpi=off
From: Miroslav Rezanina <mrezanin@xxxxxxxxxx>
Date: Fri, 16 Oct 2009 13:39:40 -0400 (EDT)
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Delivery-date: Fri, 16 Oct 2009 10:40:08 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <2100769032.331721255714626691.JavaMail.root@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
---- "Dexuan Cui" <dexuan.cui@xxxxxxxxx> wrote:

> From: "Dexuan Cui" <dexuan.cui@xxxxxxxxx>
> To: "Miroslav Rezanina" <mrezanin@xxxxxxxxxx>
> Cc: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
> Sent: Friday, October 16, 2009 4:16:55 PM GMT +01:00 Amsterdam / Berlin / 
> Bern / Rome / Stockholm / Vienna
> Subject: RE:  [Xen-changelog] [xen-unstable]vt-d: Fixpanic in 
> msi_msg_read_remap_rte with acpi=off
>
> Hi Miroslav and Keir,
> When acpi=off and we set iommu_enabled=0, the execution of xen can't
> reach the acpi_find_matched_drhd_unit Miroslav explicitly points out
> one by one.
> I think I can give a cleaner fix. Please see the attached patch.
> 
> Thanks,
> -- Dexuan
> 
Hi Dexuan,
acpi_find_matched_drhd_unit can theoretically return NULL. Is one check so big 
overhead to risk
segmentation fault? 
> 
> diff -r 0705efd9c69e xen/drivers/passthrough/iommu.c
> --- a/xen/drivers/passthrough/iommu.c   Fri Oct 16 09:04:53 2009 +0100
> +++ b/xen/drivers/passthrough/iommu.c   Fri Oct 16 18:41:46 2009 +0800
> @@ -266,9 +266,13 @@ int iommu_setup(void)
>  {
>      int rc = -ENODEV;
> 
> -    rc = iommu_hardware_setup();
> -
> -     iommu_enabled = (rc == 0);
> +    if ( acpi_disabled )
> +        iommu_enabled = 0;
> +    else
> +    {
> +        rc = iommu_hardware_setup();
> +        iommu_enabled = (rc == 0);
> +    }
> 
>     if ( force_iommu && !iommu_enabled )
>          panic("IOMMU setup failed, crash Xen for security purpose!\n");

I miss this part, so this one should be add. However, I would leave checks when 
calling acpi_find_matched_drhd_unit.
-- 
Miroslav Rezanina
Software Engineer - Virtualization Team - XEN kernel

-- 
Miroslav Rezanina
Software Engineer - Virtualization Team - XEN kernel


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>