From: "Kazlauskas, Nicholas" <Nicholas.Kazlauskas@amd.com>
To: Chris Wilson <chris@chris-wilson.co.uk>,
"igt-dev@lists.freedesktop.org" <igt-dev@lists.freedesktop.org>
Subject: Re: [igt-dev] [PATCH i-g-t 3/3] lib/fb: Clear framebuffer on amdgpu
Date: Fri, 8 Mar 2019 15:00:46 +0000 [thread overview]
Message-ID: <6cc618f5-a4a7-a63f-a126-f80b07d6ecdd@amd.com> (raw)
In-Reply-To: <155205603488.28502.11798965582789285958@skylake-alporthouse-com>
On 3/8/19 9:40 AM, Chris Wilson wrote:
> Quoting Nicholas Kazlauskas (2019-03-08 14:36:03)
>> IGT expects buffers returned from DRM_IOCTL_MODE_MAP_DUMB to be
>> cleared, but amdgpu retains the contents previously in memory
>> in the buffer - clear it on amdgpu by with a memset to 0.
>
> How is this not a kernel information leak?
> -Chris
>
I actually meant to write DRM_IOCTL_MODE_CREATE_DUMB, but it is an
information leak for whatever was previously in VRAM anyway.
With AMDGPU you have to explicitly ask for the memory to be cleared when
creating the BO with AMDGPU_GEM_CREATE_VRAM_CLEARED, but that flag isn't
one of the flags used when creating buffers for amdgpu_mode_dumb_create.
Maybe it should be, but I'd be considered with any potential performance
impact in doing so at least. I haven't done much driver benchmarking
myself to know if it's a good idea or not.
Nicholas Kazlauskas
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next prev parent reply other threads:[~2019-03-08 15:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-08 14:36 [igt-dev] [PATCH i-g-t 1/3] lib/drmtest: Add helpers to check and require amdgpu Nicholas Kazlauskas
2019-03-08 14:36 ` [igt-dev] [PATCH i-g-t 2/3] lib/debugfs: Don't do CRC sanity checks on amdgpu Nicholas Kazlauskas
2019-03-08 14:36 ` [igt-dev] [PATCH i-g-t 3/3] lib/fb: Clear framebuffer " Nicholas Kazlauskas
2019-03-08 14:40 ` Chris Wilson
2019-03-08 15:00 ` Kazlauskas, Nicholas [this message]
2019-03-08 15:08 ` Chris Wilson
2019-03-08 15:10 ` Kazlauskas, Nicholas
2019-03-08 17:45 ` [igt-dev] ✓ Fi.CI.BAT: success for series starting with [i-g-t,1/3] lib/drmtest: Add helpers to check and require amdgpu Patchwork
2019-03-08 21:30 ` [igt-dev] ✓ Fi.CI.IGT: " Patchwork
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