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Re: [Qemu-devel] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l
From: |
Mark Cave-Ayland |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l, h} during lvx instruction |
Date: |
Mon, 17 Dec 2018 17:23:36 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 |
On 17/12/2018 16:46, Richard Henderson wrote:
> On 12/17/18 4:24 AM, Mark Cave-Ayland wrote:
>> During review of the previous patch, Richard pointed out an existing bug that
>> the writeback to the avr{l,h} registers should be delayed until after any
>> exceptions have been raised.
>>
>> Perform both 64-bit loads into separate temporaries and then write them into
>> the avr{l,h} registers together to ensure that this is always the case.
>>
>> Signed-off-by: Mark Cave-Ayland <address@hidden>
>> ---
>> target/ppc/translate/vmx-impl.inc.c | 24 +++++++++++++-----------
>> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> I feel a bit silly. There was no bug, since the address is forced to be
> aligned on a 16-byte boundary. The second memory access will be to the same
> page and cannot trap.
>
> That said, I think the cleanup looks good.
>
> Reviewed-by: Richard Henderson <address@hidden>
Ah okay. I'm inclined to drop this patch for now, since it feels strange
introducing
a cleanup to just one of the load functions...
ATB,
Mark.
- [Qemu-devel] [RFC PATCH v2 0/9] target/ppc: convert VMX instructions to use TCG vector operations, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 2/9] target/ppc: introduce get_avr64() and set_avr64() helpers for VMX register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 5/9] target/ppc: switch FPR, VMX and VSX helpers to access data directly from cpu_env, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 1/9] target/ppc: introduce get_fpr() and set_fpr() helpers for FP register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 4/9] target/ppc: delay writeback of avr{l, h} during lvx instruction, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 6/9] target/ppc: merge ppc_vsr_t and ppc_avr_t union types, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 3/9] target/ppc: introduce get_cpu_vsr{l, h}() and set_cpu_vsr{l, h}() helpers for VSR register access, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 7/9] target/ppc: move FP and VMX registers into aligned vsr register array, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 9/9] target/ppc: convert vaddu[b, h, w, d] and vsubu[b, h, w, d] over to use vector operations, Mark Cave-Ayland, 2018/12/17
- [Qemu-devel] [RFC PATCH v2 8/9] target/ppc: convert VMX logical instructions to use vector operations, Mark Cave-Ayland, 2018/12/17
- Re: [Qemu-devel] [RFC PATCH v2 0/9] target/ppc: convert VMX instructions to use TCG vector operations, Richard Henderson, 2018/12/17