Re: [Qemu-devel] [Bug 788697] Re: [PowerPC] [patch] mtmsr does not preserve high bits of MSR

[Nathan Whitehorn <788697@bugs.launchpad.net>]

On 05/26/11 18:47, agraf wrote:
> On 27.05.2011, at 01:33, Nathan Whitehorn wrote:
>
>> On 05/26/11 11:45, agraf wrote:
>>> On 26.05.2011, at 18:09, Nathan Whitehorn wrote:
>>>
>>>> ** Patch added: "mtmstr.diff"
>>>>    https://bugs.launchpad.net/bugs/788697/+attachment/2143748/+files/mtmstr.diff
>>>>
>>>> --
>>>> You received this bug notification because you are a member of qemu-
>>>> devel-ml, which is subscribed to QEMU.
>>>> https://bugs.launchpad.net/bugs/788697
>>>>
>>>> Title:
>>>>   [PowerPC] [patch] mtmsr does not preserve high bits of MSR
>>>>
>>>> Status in QEMU:
>>>>   New
>>>>
>>>> Bug description:
>>>>   The mtmsr instruction on 64-bit PPC does not preserve the high-order
>>>>   32-bits of the MSR the way it is supposed to, instead setting them to
>>>>   0, which takes 64-bit code out of 64-bit mode. There is some code that
>>>>   does the right thing, but it brokenly only preserves these bits when
>>>>   the thread is not in 64-bit mode (i.e. when it doesn't matter). The
>>>>   attached patch unconditionally enables this code when TARGET_PPC64 is
>>>>   set, per the ISA spec, which fixes early boot failures trying to start
>>>>   FreeBSD/powerpc64 under qemu.
>>>>
>>> Please send the patch as proper patch to the ML and CC me.
>> What isn't proper about the patch? I'm happy to re-email it, but don't
>> want things to be in the wrong format.
>> -Nathan
> The patch needs a patch description in its header and a subject line
> (all of which are present in the bug, so it's a simple matter of
> copy&paste). Basically at the end of the day, I should be able to save
> the mail and "git am" on it and simply have it in my tree :).
>
> Also, does this get FreeBSD booting up to anything useful, so I can
> verify it helps?

OK, I'll send this one out to today. The other issue I'm having (aside 
from our own bugs), is that SPR_PIR is not implemented for the POWER7 
target. The architecture manual claims it is implemented on all Book-3S 
compliant CPUs, but it seems to be implemented sort of ad-hoc in 
target-ppc.c (e.g. the 604, 620, and 7400 have it, but not the 750, 970, 
or POWER7).
-Nathan

-- 
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https://bugs.launchpad.net/bugs/788697

Title:
  [PowerPC] [patch] mtmsr does not preserve high bits of MSR

Status in QEMU:
  New

Bug description:
  The mtmsr instruction on 64-bit PPC does not preserve the high-order
  32-bits of the MSR the way it is supposed to, instead setting them to
  0, which takes 64-bit code out of 64-bit mode. There is some code that
  does the right thing, but it brokenly only preserves these bits when
  the thread is not in 64-bit mode (i.e. when it doesn't matter). The
  attached patch unconditionally enables this code when TARGET_PPC64 is
  set, per the ISA spec, which fixes early boot failures trying to start
  FreeBSD/powerpc64 under qemu.