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From: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
To: Alistair Francis <alistair23@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>,
	qemu-devel <qemu-devel@nongnu.org>,
	"qemu-riscv@nongnu.org" <qemu-riscv@nongnu.org>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	liweiwei <liweiwei@iscas.ac.cn>,
	Christoph Muellner <christoph.muellner@vrull.eu>
Subject: Re: Host riscv disas is broken
Date: Fri, 6 Dec 2024 11:39:00 +0800	[thread overview]
Message-ID: <750f1e4e-0efa-43d2-9100-be8d59a23f02@linux.alibaba.com> (raw)
In-Reply-To: <CAKmqyKN+gGMFxvbRwgq5oWs9=zuAmwpMY9nFtRbmuWVB3Fjrzg@mail.gmail.com>

Hey Alistair,

On 2024/12/4 10:45, Alistair Francis wrote:
> On Thu, Oct 17, 2024 at 2:39 PM LIU Zhiwei <zhiwei_liu@linux.alibaba.com> wrote:
>>
>> On 2024/10/17 11:52, Richard Henderson wrote:
>>> On 10/16/24 19:57, LIU Zhiwei wrote:
>>>> Hi Richard,
>>>>
>>>> On 2024/10/17 02:38, Richard Henderson wrote:
>>>>> 2595: if (dec->cfg->ext_zcmop) {
>>>>> 2690:                if (dec->cfg->ext_zcmp && ((inst >> 12) & 0b01)) {
>>>>> 2716:                        if (!dec->cfg->ext_zcmt) {
>>>>> 2726:                        if (!dec->cfg->ext_zcmp) {
>>>>> 4028:                if (dec->cfg->ext_zimop) {
>>>>> 5044:            if (dec->cfg->ext_zfinx) {
>>>>> 5051:            if (dec->cfg->ext_zfinx) {
>>>>> 5058:            if (dec->cfg->ext_zfinx) {
>>>>> 5065:            if (dec->cfg->ext_zfinx) {
>>>>> 5371:        if (guard_func(cfg)) {
>>>>>
>>>>> This structure comes from RISCVCPU, a target structure.
>>>> Oops. We missed this.
>>>>> There is no such structure for the host, causing null pointer
>>>>> dereferences.
>>>>>
>>>>> The zfinx references can be changed to
>>>>>
>>>>>      dec->cfg && dec->cfg->ext_zfinx
>>>>>
>>>>> but some of them can simply be removed, e.g. zcmop and zimop, which
>>>>> are otherwise reserved encodings.
>> Yes. Maybe it is better to disassemble them as usual even when there are
>> disabled or not supported.
>>>> Should we probe the host feature like what we do in tcg backend
>>>> support and then do the right disassemble according to the probe result?
>>> I don't think there's anything that is currently checked in
>>> disas/riscv.c that needs to know about the host.  And, as I say above,
>>> some of those checks can be eliminated.
>>>
>>> Host disassembly needs are limited to what tcg/riscv/ emits.
>> Agree.
> Hey Zhiwei,
>
> Did you follow up on this?

Yes, I have recently sent a patch to fix this.

https://lists.gnu.org/archive/html/qemu-riscv/2024-12/msg00150.html

Zhiwei

>
> Alistair


      reply	other threads:[~2024-12-06  3:39 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-16 18:38 Host riscv disas is broken Richard Henderson
2024-10-17  2:57 ` LIU Zhiwei
2024-10-17  3:52   ` Richard Henderson
2024-10-17  5:38     ` LIU Zhiwei
2024-12-04  2:45       ` Alistair Francis
2024-12-06  3:39         ` LIU Zhiwei [this message]

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