From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>, Stefan Weil <sw@weilnetz.de>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Eduardo Habkost <ehabkost@redhat.com>,
Paul Durrant <paul@xen.org>,
QEMU Developers <qemu-devel@nongnu.org>,
"open list:X86" <xen-devel@lists.xenproject.org>,
Anthony Perard <anthony.perard@citrix.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH] Avoid cpu_physical_memory_rw() with a constant is_write argument
Date: Tue, 18 Feb 2020 21:07:18 +0100 [thread overview]
Message-ID: <af34169f-fccc-da44-7b8e-1b38da4a203c@redhat.com> (raw)
In-Reply-To: <CAFEAcA9Jr2Yi1K8_9MGUJYt8C=OcKbWDh1UJjTQG1EspLux3JQ@mail.gmail.com>
On 2/18/20 7:49 PM, Peter Maydell wrote:
> On Tue, 18 Feb 2020 at 17:57, Stefan Weil <sw@weilnetz.de> wrote:
>>
>> Am 18.02.20 um 14:20 schrieb Philippe Mathieu-Daudé:
>>
>>> This commit was produced with the included Coccinelle script
>>> scripts/coccinelle/as-rw-const.patch.
>>>
>>> Inspired-by: Peter Maydell <peter.maydell@linaro.org>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> ---
>>> Based-on: <20200218112457.22712-1-peter.maydell@linaro.org>
>> [...]
>>> diff --git a/target/i386/hax-all.c b/target/i386/hax-all.c
>>> index a8b6e5aeb8..f5971ccc74 100644
>>> --- a/target/i386/hax-all.c
>>> +++ b/target/i386/hax-all.c
>>> @@ -376,8 +376,8 @@ static int hax_handle_fastmmio(CPUArchState *env, struct hax_fastmmio *hft)
>>> * hft->direction == 2: gpa ==> gpa2
>>> */
>>> uint64_t value;
>>> - cpu_physical_memory_rw(hft->gpa, (uint8_t *) &value, hft->size, 0);
>>> - cpu_physical_memory_rw(hft->gpa2, (uint8_t *) &value, hft->size, 1);
>>> + cpu_physical_memory_read(hft->gpa, (uint8_t *)&value, hft->size);
>>> + cpu_physical_memory_write(hft->gpa2, (uint8_t *)&value, hft->size);
>>
>>
>> Maybe those type casts could be removed, too. They are no longer needed
>> after your modification.
>
> I think that we should fix the inconsistency where these functions
> all take "uint8_t* buf":
>
> - address_space_rw()
> - address_space_read()
> - address_space_write()
> - address_space_write_rom()
> - cpu_physical_memory_rw()
> - cpu_memory_rw_debug()
>
> but these take void*:
> - cpu_physical_memory_read()
> - cpu_physical_memory_write()
> - address_space_write_cached()
> - address_space_read_cached_slow()
> - address_space_write_cached_slow()
> - pci_dma_read()
> - pci_dma_write()
> - pci_dma_rw()
> - dma_memory_read()
> - dma_memory_write()
> - dma_memory_rw()
> - dma_memory_rw_relaxed()
I don't understand well cpu_physical_memory*(). Aren't these obsolete?
They confuse me when using multi-core CPUs.
>
> Depending on which way we go we would either want to remove these
> casts, or not.
>
> I guess that we have more cases of 'void*', and that would
> certainly be the easier way to convert (otherwise we probably
> need to add a bunch of new casts to uint8_t* in various callsites),
> but I don't have a strong opinion. Paolo ?
I thought about it too but it is quite some work, and I'v to admit I
lost some faith with my previous chardev conversion. There Paolo/Daniel
agreed to follow the libc read()/write() prototypes.
>
> thanks
> -- PMM
>
next prev parent reply other threads:[~2020-02-18 20:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 13:20 [PATCH] Avoid cpu_physical_memory_rw() with a constant is_write argument Philippe Mathieu-Daudé
2020-02-18 17:39 ` Richard Henderson
2020-02-18 17:57 ` Stefan Weil
2020-02-18 18:13 ` Philippe Mathieu-Daudé
2020-02-18 18:49 ` Peter Maydell
2020-02-18 18:59 ` Stefan Weil
2020-02-18 19:00 ` Stefan Weil
2020-02-18 19:14 ` Richard Henderson
2020-02-18 20:07 ` Philippe Mathieu-Daudé [this message]
2020-02-18 21:16 ` Peter Maydell
2020-02-20 11:32 ` Paolo Bonzini
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