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Subject: Re: [PATCH] virtio-console: avoid DMA from vmalloc area
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Amit Shah <amit@kernel.org>, gregkh <gregkh@linuxfoundation.org>,
        Omar Sandoval <osandov@fb.com>,
        "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" 
        <virtualization@lists.linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
References: <20210727131217.15092-1-xianting.tian@linux.alibaba.com>
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 <be29127d-8cec-c7b8-ac96-4da94198dc03@linux.alibaba.com>
 <CAK8P3a1O02Ho2dM3F+bUXf9Ze8uRKYzY5fFmRGpszUXg_nrH4w@mail.gmail.com>
 <0d03a42b-b46c-408f-17a4-b6c094c0c29e@linux.alibaba.com>
 <CAK8P3a2Hde16rbUPAwvtY7t+uE7C4jM8_pQCqTLj=-d4=T2MSg@mail.gmail.com>
From:   Xianting Tian <xianting.tian@linux.alibaba.com>
Message-ID: <d3760b84-82b6-d8e1-0fed-dc494d226f3f@linux.alibaba.com>
Date:   Wed, 28 Jul 2021 17:10:35 +0800
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在 2021/7/28 下午5:01, Arnd Bergmann 写道:
> On Wed, Jul 28, 2021 at 10:28 AM Xianting Tian
> <xianting.tian@linux.alibaba.com> wrote:
>> 在 2021/7/28 下午3:25, Arnd Bergmann 写道:
>>
>> I checked several hvc backends, like drivers/tty/hvc/hvc_riscv_sbi.c,
>> drivers/tty/hvc/hvc_iucv.c, drivers/tty/hvc/hvc_rtas.c, they don't use dma.
>>
>> I not finished all hvc backends check yet. But I think even if all hvc
>> backends don't use dma currently, it is still possible that the hvc
>> backend using dma will be added in the furture.
>>
>> So I agree with you it should better be fixed in the hvc framework,
>> solve the issue in the first place.
> Ok, sounds good to me, no need to check more backends then.
> I see the hvc-console driver is listed as 'Odd Fixes' in the maintainer
> list, with nobody assigned other than the ppc kernel list (added to Cc).
>
> Once you come up with a fix in hvc_console.c, please send that to the
> tty maintainers, the ppc list and me, and I'll review it.
OK, thanks, I will submit the patch ASAP :)
>
>          Arnd