Message-ID: <e7cad6ca-d106-c529-6f22-93a7847cd7c0@intel.com>
Date:   Mon, 13 Dec 2021 13:02:44 +0000
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.3.0
Subject: Re: [PATCH] drm/i915/ttm: fix large buffer population trucation
Content-Language: en-GB
To:     Robert Beckett <bob.beckett@collabora.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= 
        <thomas.hellstrom@linux.intel.com>, Oak Zeng <oak.zeng@intel.com>
Cc:     intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
References: <20211210195005.2582884-1-bob.beckett@collabora.com>
From:   Matthew Auld <matthew.auld@intel.com>
In-Reply-To: <20211210195005.2582884-1-bob.beckett@collabora.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10/12/2021 19:50, Robert Beckett wrote:
> ttm->num_pages is uint32_t which was causing very large buffers to
> only populate a truncated size.
> 
> This fixes gem_create@create-clear igt test on large memory systems.
> 
> Fixes: 7ae034590cea ("drm/i915/ttm: add tt shmem backend")
> Signed-off-by: Robert Beckett <bob.beckett@collabora.com>

Nice catch,
Reviewed-by: Matthew Auld <matthew.auld@intel.com>

> ---
>   drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 218a9b3037c7..923cc7ad8d70 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -166,7 +166,7 @@ static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
>   	struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM];
>   	struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
>   	const unsigned int max_segment = i915_sg_segment_size();
> -	const size_t size = ttm->num_pages << PAGE_SHIFT;
> +	const size_t size = (size_t)ttm->num_pages << PAGE_SHIFT;
>   	struct file *filp = i915_tt->filp;
>   	struct sgt_iter sgt_iter;
>   	struct sg_table *st;
>