Re: [Qemu-devel] [PATCH v2 0/8] target-arm: Translate based on TB flags, not CPUState

[Aurelien Jarno]

On Tue, Jan 11, 2011 at 10:12:10PM +0000, Peter Maydell wrote:
> This patchset corrects a number of places in the ARM translation code
> which were generating code which was dependent on values in the CPUState
> structure which might change at runtime. This is a bad idea for two
> reasons. Firstly, we might try to reuse the generated code later when
> the assumptions baked into the generated code were no longer valid.
> Secondly, we might try to retranslate the same TB (eg when an exception
> results in our calling cpu_restore_state()) but get different generated
> code, which could result in qemu crashing.
> 
> Bug https://bugs.launchpad.net/bugs/604872 is a particular example
> of the latter case involving the IT bits; this patchset fixes that bug.
> 
> I believe that this patchset deals with all the problems. Remaining
> CPUState fields referred to in translate.c are either constant after
> system init or trigger flushing of affected TBs when they are changed.
> 
> Differences from v1: I've added some macros for the TB flags bitfields,
> as suggested by Aurelien.
> 
> Peter Maydell (8):
>   target-arm: Don't generate code specific to current CPU mode for SRS
>   target-arm: Add symbolic constants for bitfields in TB flags
>   target-arm: Translate with VFP-enabled from TB flags, not CPUState
>   target-arm: Translate with VFP len/stride from TB flags, not CPUState
>   target-arm: Translate with Thumb state from TB flags, not CPUState
>   target-arm: Translate with condexec bits from TB flags, not CPUState
>   target-arm: Set privileged bit in TB flags correctly for M profile
>   target-arm: Translate with user-state from TB flags, not CPUState
> 
>  target-arm/cpu.h       |   51 ++++++++++++++++++++++++---
>  target-arm/helper.c    |   12 +++++-
>  target-arm/translate.c |   88 ++++++++++++++++++-----------------------------
>  3 files changed, 89 insertions(+), 62 deletions(-)
> 
> 
> 

Thanks, all applied.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net