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Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64 |
Date: |
Sat, 21 May 2011 11:44:55 +0200 |
On 21.05.2011, at 11:39, Andreas Färber wrote:
> Am 21.05.2011 um 03:58 schrieb Alexander Graf:
>
>> Am 21.05.2011 um 00:37 schrieb Andreas Färber <address@hidden>:
>>
>>> Am 20.05.2011 um 09:40 schrieb Alexander Graf:
>>>
>>>> On 20.05.2011, at 05:34, David Gibson wrote:
>>>>
>>>>> Early ppc64 CPUs include a hack to partially simulate the ppc32 segment
>>>>> registers, by translating writes to them into writes to the SLB. This is
>>>>> not used by any current Linux kernel, but it is used by the openbios used
>>>>> in the qemu mac99 model.
>>>>>
>>>>> Commit 81762d6dd0d430d87024f2c83e9c4dcc4329fb7d, cleaning up the SLB
>>>>> handling introduced a bug in this code, breaking the openbios currently in
>>>>> qemu. Specifically, there was an off by one error bitshuffling the
>>>>> register format used by mtsr into the format needed for the SLB load,
>>>>> causing the flag bits to end up in the wrong place. This caused the
>>>>> storage keys to be wrong under openbios, meaning that the translation code
>>>>> incorrectly thought a legitimate access was a permission violation.
>>>>>
>>>>> This patch fixes the bug, at the same time it fixes some build bug in the
>>>>> MMU debugging code (only exposed when DEBUG_MMU is enabled).
>>>>
>>>> Thanks, applied to ppc-next :)
>>>
>>> Nack, this does not fix ppc64 for me! How did you test it, Alex???
>>
>> I booted a ppc64 kernel on a ppc64 Linux system with tcg and it booted fine
>> for me. Maybe you're hitting yet another issue?
>
> Which OpenBIOS did you use? The 32-bit version using mtsrin works now, but
> not the 64-bit HEAD version that I attached, which uses slb* instructions
> instead.
Ah, I see. I tested the binary that's in pc-bios, so the 32-bit version
obviously. So your 64-bit build regresses?
Alex
- [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, David Gibson, 2011/05/19
- Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, Andreas Färber, 2011/05/21
- Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, Alexander Graf, 2011/05/21
- Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, David Gibson, 2011/05/21
- Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, Alexander Graf, 2011/05/21
Re: [Qemu-devel] [PATCH] Fix a bug in mtsr/mtsrin emulation on ppc64, Andreas Färber, 2011/05/21