[Mesa-dev] [PATCH v3] anv: Limit VkDeviceMemory objects to 2GB

[Juan A. Suarez Romero]

Reviewed-by: Juan A. Suarez Romero <jasuarez at igalia.com>

On Tue, 2017-04-11 at 11:11 -0700, Jason Ekstrand wrote:
> v2 (Jason Ekstrand):
>  - Limit to 2GB instead of 4GB
> 
> v3 (Jason Ekstrand):
>  - Fix the build by using pAllocateInfo instead of pAllocationInfo (not
>    sure how that happened).
>  - Return vK_ERROR_OUT_OF_DEVICE_MEMORY (Thanks Ilia!)
> 
> Cc: "Juan A. Suárez" <jasuarez at igalia.com>
> ---
>  src/intel/vulkan/anv_device.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
> index 35ef4c4..ee9c48f 100644
> --- a/src/intel/vulkan/anv_device.c
> +++ b/src/intel/vulkan/anv_device.c
> @@ -1539,6 +1539,26 @@ VkResult anv_AllocateMemory(
>     assert(pAllocateInfo->memoryTypeIndex == 0 ||
>            (!device->info.has_llc && pAllocateInfo->memoryTypeIndex < 2));
>  
> +   /* The kernel relocation API has a limitation of a 32-bit delta value
> +    * applied to the address before it is written which, in spite of it being
> +    * unsigned, is treated as signed .  Because of the way that this maps to
> +    * the Vulkan API, we cannot handle an offset into a buffer that does not
> +    * fit into a signed 32 bits.  The only mechanism we have for dealing with
> +    * this at the moment is to limit all VkDeviceMemory objects to a maximum
> +    * of 2GB each.  The Vulkan spec allows us to do this:
> +    *
> +    *    "Some platforms may have a limit on the maximum size of a single
> +    *    allocation. For example, certain systems may fail to create
> +    *    allocations with a size greater than or equal to 4GB. Such a limit is
> +    *    implementation-dependent, and if such a failure occurs then the error
> +    *    VK_ERROR_OUT_OF_DEVICE_MEMORY should be returned."
> +    *
> +    * We don't use vk_error here because it's not an error so much as an
> +    * indication to the application that the allocation is too large.
> +    */
> +   if (pAllocateInfo->allocationSize > (1ull << 31))
> +      return VK_ERROR_OUT_OF_DEVICE_MEMORY;
> +
>     /* FINISHME: Fail if allocation request exceeds heap size. */
>  
>     mem = vk_alloc2(&device->alloc, pAllocator, sizeof(*mem), 8,