From: Julien Grall <julien.grall@arm.com>
To: Shanker Donthineni <shankerd@codeaurora.org>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Philip Elcan <pelcan@codeaurora.org>,
Vikram Sethi <vikrams@codeaurora.org>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Will Deacon <will.deacon@arm.com>,
Jan Beulich <JBeulich@suse.com>,
Andre Przywara <Andre.Przywara@arm.com>
Subject: Re: [PATCH v3] arm: Fix asynchronous aborts (SError exceptions) due to bogus PTEs
Date: Fri, 8 Apr 2016 10:42:52 +0100 [thread overview]
Message-ID: <57077D1C.9000902@arm.com> (raw)
In-Reply-To: <57055C37.1000403@codeaurora.org>
On 06/04/16 19:57, Shanker Donthineni wrote:
> Hi Julien/Stefano,
Hi Shanker,
>
> Any other comments to be addressed? Please propose an alternative
> solution to fix the problem if this patch changes are not appropriate.
All the comments have been addressed.
>
> On 03/28/2016 11:46 PM, Shanker Donthineni wrote:
>> From: Vikram Sethi <vikrams@codeaurora.org>
>>
>> ARMv8 architecture allows performing prefetch data/instructions
>> from memory locations marked as normal memory. Prefetch does not
>> mean that the data/instruction has to be used/executed in code
>> flow. All PTEs that appear to be valid to MMU must contain valid
>> physical address with proper attributes otherwise MMU table walk
>> might cause imprecise asynchronous aborts.
>>
>> The way current XEN code is preparing page tables for frametable
>> and xenheap memory can create bogus PTEs. This patch fixes the
>> issue by clearing page table memory before populating EL2 L0/L1
>> PTEs. Without this patch XEN crashes on Qualcomm Technologies
>> server chips due to asynchronous aborts.
>>
>> The speculative/prefetch feature explanation is scattered everywhere
>> in ARM specification but below two sections have useful information.
>>
>> E2.8 Memory types and attributes (ver DDI0487A_h)
>> G4.12.6 External abort on a translation table walk (ver DDI0487A_h)
>>
>> Signed-off-by: Vikram Sethi <vikrams@codeaurora.org>
>> Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Acked-by: Julien Grall <julien.grall@arm.com>
Regards,
--
Julien Grall
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next prev parent reply other threads:[~2016-04-08 9:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-29 4:46 [PATCH v3] arm: Fix asynchronous aborts (SError exceptions) due to bogus PTEs Shanker Donthineni
2016-04-06 18:06 ` Shanker Donthineni
2016-04-06 18:57 ` Shanker Donthineni
2016-04-08 9:42 ` Julien Grall [this message]
2016-04-08 15:21 ` Konrad Rzeszutek Wilk
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