Module: Mesa Branch: main Commit: 21f0fc65b22afec2bbc173a766ce2d68f8515a25 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=21f0fc65b22afec2bbc173a766ce2d68f8515a25
Author: Luigi Santivetti <[email protected]> Date: Fri Jan 20 14:57:47 2023 +0000 pvr: add padding bytes when allocating buffer memory We need to pad VkBuffers to ensure we don't read beyond a page boundary. An alternative to this approach would be to allocate an additional virtual page when binding memory to the buffer, and to map this to the first physical address, so both the first and last virtual page point to the same physical location. This would be less expensive in terms of memory usage, but more complex and invasive, hence the simpler approach has been taken for now. Signed-off-by: Luigi Santivetti <[email protected]> Reviewed-by: Frank Binns <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21101> --- src/imagination/vulkan/pvr_device.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/src/imagination/vulkan/pvr_device.c b/src/imagination/vulkan/pvr_device.c index 98f10af0c02..18c9449fc5c 100644 --- a/src/imagination/vulkan/pvr_device.c +++ b/src/imagination/vulkan/pvr_device.c @@ -87,6 +87,11 @@ .name = str_name, .len = sizeof(str_name) - 1 \ } +/* Amount of padding required for VkBuffers to ensure we don't read beyond + * a page boundary. + */ +#define PVR_BUFFER_MEMORY_PADDING_SIZE 4 + struct pvr_drm_device_info { const char *name; size_t len; @@ -2957,6 +2962,7 @@ void pvr_GetBufferMemoryRequirements2( { PVR_FROM_HANDLE(pvr_buffer, buffer, pInfo->buffer); PVR_FROM_HANDLE(pvr_device, device, _device); + uint64_t size; /* The Vulkan 1.0.166 spec says: * @@ -2971,8 +2977,21 @@ void pvr_GetBufferMemoryRequirements2( (1ul << device->pdevice->memory.memoryTypeCount) - 1; pMemoryRequirements->memoryRequirements.alignment = buffer->alignment; + + size = buffer->vk.size; + + if (size % device->ws->page_size == 0 || + size % device->ws->page_size > + device->ws->page_size - PVR_BUFFER_MEMORY_PADDING_SIZE) { + /* TODO: We can save memory by having one extra virtual page mapped + * in and having the first and last virtual page mapped to the first + * physical address. + */ + size += PVR_BUFFER_MEMORY_PADDING_SIZE; + } + pMemoryRequirements->memoryRequirements.size = - ALIGN_POT(buffer->vk.size, buffer->alignment); + ALIGN_POT(size, buffer->alignment); } void pvr_GetImageMemoryRequirements2(VkDevice _device,
