From: Don Dutile <ddutile@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: indou.takao@jp.fujitsu.com, bhe@redhat.com,
linux-pci@vger.kernel.org, joro@8bytes.org,
kexec@lists.infradead.org, alex.williamson@redhat.com,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
doug.hatch@hp.com, ishii.hironobu@jp.fujitsu.com,
bhelgaas@google.com, zhenhua@hp.com,
Bill Sumner <bill.sumner@hp.com>
Subject: Re: [PATCHv3 0/6] Crashdump Accepting Active IOMMU
Date: Tue, 08 Apr 2014 14:42:56 -0400 [thread overview]
Message-ID: <53444330.2030606@redhat.com> (raw)
In-Reply-To: <1396973686.25235.36.camel@i7.infradead.org>
On 04/08/2014 12:14 PM, David Woodhouse wrote:
> On Mon, 2014-04-07 at 16:43 -0400, Don Dutile wrote:
>>
>> Additionally, a tidbit of information like "some servers force NMI's
>> on DMAR faults,
>> and cause a system reset, thereby, preventing a kdump to occur"
>> should have been included as one reason to stop DMAR faults from
>> occurring on kexec-boot,
>> in addition to the fact that a flood of them can lock up a system.
>
> How about allocating a physical scratch page, and setting up a mapping
> for each device such that *every* virtual address (apart from those
> listed in RMRRs, perhaps) is mapped to that same scratch page?
>
> That way you avoid the faults, but you also avoid stray DMA to parts of
> the system that you don't want to get corrupted.
>
+1... more isolation as second kernel booting sounds good.
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WARNING: multiple messages have this Message-ID (diff)
From: Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
doug.hatch-VXdhtT5mjnY@public.gmane.org,
ishii.hironobu-+CUm20s59erQFUHtdCDX3A@public.gmane.org,
bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
zhenhua-VXdhtT5mjnY@public.gmane.org,
Bill Sumner <bill.sumner-VXdhtT5mjnY@public.gmane.org>
Subject: Re: [PATCHv3 0/6] Crashdump Accepting Active IOMMU
Date: Tue, 08 Apr 2014 14:42:56 -0400 [thread overview]
Message-ID: <53444330.2030606@redhat.com> (raw)
In-Reply-To: <1396973686.25235.36.camel-W2I5cNIroUsVm/YvaOjsyQ@public.gmane.org>
On 04/08/2014 12:14 PM, David Woodhouse wrote:
> On Mon, 2014-04-07 at 16:43 -0400, Don Dutile wrote:
>>
>> Additionally, a tidbit of information like "some servers force NMI's
>> on DMAR faults,
>> and cause a system reset, thereby, preventing a kdump to occur"
>> should have been included as one reason to stop DMAR faults from
>> occurring on kexec-boot,
>> in addition to the fact that a flood of them can lock up a system.
>
> How about allocating a physical scratch page, and setting up a mapping
> for each device such that *every* virtual address (apart from those
> listed in RMRRs, perhaps) is mapped to that same scratch page?
>
> That way you avoid the faults, but you also avoid stray DMA to parts of
> the system that you don't want to get corrupted.
>
+1... more isolation as second kernel booting sounds good.
WARNING: multiple messages have this Message-ID (diff)
From: Don Dutile <ddutile@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Bill Sumner <bill.sumner@hp.com>,
indou.takao@jp.fujitsu.com, bhe@redhat.com, joro@8bytes.org,
iommu@lists.linux-foundation.org, kexec@lists.infradead.org,
alex.williamson@redhat.com, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, ishii.hironobu@jp.fujitsu.com,
bhelgaas@google.com, doug.hatch@hp.com, zhenhua@hp.com
Subject: Re: [PATCHv3 0/6] Crashdump Accepting Active IOMMU
Date: Tue, 08 Apr 2014 14:42:56 -0400 [thread overview]
Message-ID: <53444330.2030606@redhat.com> (raw)
In-Reply-To: <1396973686.25235.36.camel@i7.infradead.org>
On 04/08/2014 12:14 PM, David Woodhouse wrote:
> On Mon, 2014-04-07 at 16:43 -0400, Don Dutile wrote:
>>
>> Additionally, a tidbit of information like "some servers force NMI's
>> on DMAR faults,
>> and cause a system reset, thereby, preventing a kdump to occur"
>> should have been included as one reason to stop DMAR faults from
>> occurring on kexec-boot,
>> in addition to the fact that a flood of them can lock up a system.
>
> How about allocating a physical scratch page, and setting up a mapping
> for each device such that *every* virtual address (apart from those
> listed in RMRRs, perhaps) is mapped to that same scratch page?
>
> That way you avoid the faults, but you also avoid stray DMA to parts of
> the system that you don't want to get corrupted.
>
+1... more isolation as second kernel booting sounds good.
next prev parent reply other threads:[~2014-04-08 18:44 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-10 22:07 [PATCHv3 0/6] Crashdump Accepting Active IOMMU Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` [PATCHv3 1/6] Crashdump-Accepting-Active-IOMMU-Flags-and-Prototype Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` [PATCHv3 2/6] Crashdump-Accepting-Active-IOMMU-Utility-functions Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` [PATCHv3 3/6] Crashdump-Accepting-Active-IOMMU-Domain-Interfaces Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-03-04 14:59 ` Joerg Roedel
2014-03-04 14:59 ` Joerg Roedel
2014-03-04 14:59 ` Joerg Roedel
2014-03-10 19:23 ` Sumner, William
2014-03-10 19:23 ` Sumner, William
2014-01-10 22:07 ` [PATCHv3 4/6] Crashdump-Accepting-Active-IOMMU-Copy-Translations Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` [PATCHv3 5/6] Crashdump-Accepting-Active-IOMMU-Debug-Print-IOMMU Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` [PATCHv3 6/6] Crashdump-Accepting-Active-IOMMU-Call-From-Mainline Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-10 22:07 ` Bill Sumner
2014-01-25 2:44 ` [PATCHv3 0/6] Crashdump Accepting Active IOMMU Baoquan He
2014-01-25 2:44 ` Baoquan He
2014-01-25 2:44 ` Baoquan He
2014-03-04 15:06 ` Joerg Roedel
2014-03-04 15:06 ` Joerg Roedel
2014-03-04 15:06 ` Joerg Roedel
2014-03-10 19:10 ` Sumner, William
2014-03-10 19:10 ` Sumner, William
2014-03-10 19:10 ` Sumner, William
2014-03-10 21:43 ` Vivek Goyal
2014-03-10 21:43 ` Vivek Goyal
2014-03-10 21:43 ` Vivek Goyal
2014-04-07 20:43 ` Don Dutile
2014-04-07 20:43 ` Don Dutile
2014-04-07 20:43 ` Don Dutile
2014-04-08 16:14 ` David Woodhouse
2014-04-08 16:14 ` David Woodhouse
2014-04-08 18:42 ` Don Dutile [this message]
2014-04-08 18:42 ` Don Dutile
2014-04-08 18:42 ` Don Dutile
2014-04-25 18:11 ` Sumner, William
2014-04-25 18:11 ` Sumner, William
2014-04-25 18:11 ` Sumner, William
-- strict thread matches above, loose matches on Subject: below --
2014-03-12 16:15 Sumner, William
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