vulkan/wsi/sw: add support for using host_ptr for shm pixmaps.

This pipes the allocation of the MIT-SHM pixmap into the wsi common
code to callback to the x11 path to allocate things in the right place.

Acked-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12482>

src/vulkan/wsi/wsi_common_display.c

@@ -1031,7 +1031,7 @@ wsi_display_image_init(VkDevice device_h,
       return VK_ERROR_DEVICE_LOST;
 
    VkResult result = wsi_create_native_image(&chain->base, create_info,
-                                             0, NULL, NULL,
+                                             0, NULL, NULL, NULL,
                                              &image->base);
    if (result != VK_SUCCESS)
       return result;

src/vulkan/wsi/wsi_common_drm.c

@@ -107,6 +107,7 @@ wsi_create_native_image(const struct wsi_swapchain *chain,
                         uint32_t num_modifier_lists,
                         const uint32_t *num_modifiers,
                         const uint64_t *const *modifiers,
+                        uint8_t *(alloc_shm)(struct wsi_image *image, unsigned size),
                         struct wsi_image *image)
 {
    const struct wsi_device *wsi = chain->wsi;
@@ -297,6 +298,19 @@ wsi_create_native_image(const struct wsi_swapchain *chain,
    VkMemoryRequirements reqs;
    wsi->GetImageMemoryRequirements(chain->device, image->image, &reqs);
 
+   void *sw_host_ptr = NULL;
+   if (alloc_shm) {
+      VkSubresourceLayout layout;
+
+      wsi->GetImageSubresourceLayout(chain->device, image->image,
+                                     &(VkImageSubresource) {
+                                        .aspectMask = VK_IMAGE_ASPECT_COLOR_BIT,
+                                        .mipLevel = 0,
+                                        .arrayLayer = 0,
+                                     }, &layout);
+      sw_host_ptr = (*alloc_shm)(image, layout.size);
+   }
+
    const struct wsi_memory_allocate_info memory_wsi_info = {
       .sType = VK_STRUCTURE_TYPE_WSI_MEMORY_ALLOCATE_INFO_MESA,
       .pNext = NULL,
@@ -313,9 +327,14 @@ wsi_create_native_image(const struct wsi_swapchain *chain,
       .image = image->image,
       .buffer = VK_NULL_HANDLE,
    };
+   const VkImportMemoryHostPointerInfoEXT host_ptr_info = {
+      .sType = VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT,
+      .pNext = &memory_dedicated_info,
+      .pHostPointer = sw_host_ptr,
+   };
    const VkMemoryAllocateInfo memory_info = {
       .sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO,
-      .pNext = &memory_dedicated_info,
+      .pNext = sw_host_ptr ? (void *)&host_ptr_info : (void *)&memory_dedicated_info,
       .allocationSize = reqs.size,
       .memoryTypeIndex = select_memory_type(wsi, true, reqs.memoryTypeBits),
    };

src/vulkan/wsi/wsi_common_private.h

@@ -94,6 +94,7 @@ wsi_create_native_image(const struct wsi_swapchain *chain,
                         uint32_t num_modifier_lists,
                         const uint32_t *num_modifiers,
                         const uint64_t *const *modifiers,
+                        uint8_t *(alloc_shm)(struct wsi_image *image, unsigned size),
                         struct wsi_image *image);
 
 VkResult

src/vulkan/wsi/wsi_common_wayland.c

@@ -1015,7 +1015,7 @@ wsi_wl_image_init(struct wsi_wl_swapchain *chain,
    result = wsi_create_native_image(&chain->base, pCreateInfo,
                                     chain->num_drm_modifiers > 0 ? 1 : 0,
                                     &chain->num_drm_modifiers,
-                                    &chain->drm_modifiers, &image->base);
+                                    &chain->drm_modifiers, NULL, &image->base);
 
    if (result != VK_SUCCESS)
       return result;

src/vulkan/wsi/wsi_common_win32.c

@@ -301,6 +301,7 @@ wsi_create_native_image(const struct wsi_swapchain *chain,
                         uint32_t num_modifier_lists,
                         const uint32_t *num_modifiers,
                         const uint64_t *const *modifiers,
+                        uint8_t *(alloc_shm)(struct wsi_image *image, unsigned size),
                         struct wsi_image *image)
 {
    const struct wsi_device *wsi = chain->wsi;
@@ -432,7 +433,7 @@ wsi_win32_image_init(VkDevice device_h,
    struct wsi_win32_swapchain *chain = (struct wsi_win32_swapchain *) drv_chain;
 
    VkResult result = wsi_create_native_image(&chain->base, create_info,
-                                             0, NULL, NULL,
+                                             0, NULL, NULL, NULL,
                                              &image->base);
    if (result != VK_SUCCESS)
       return result;

src/vulkan/wsi/wsi_common_x11.c

@@ -833,6 +833,9 @@ struct x11_image {
    struct xshmfence *                        shm_fence;
    uint32_t                                  sync_fence;
    uint32_t                                  serial;
+   xcb_shm_seg_t                             shmseg;
+   uint32_t                                  shmid;
+   uint8_t *                                 shmaddr;
 };
 
 struct x11_swapchain {
@@ -1338,6 +1341,29 @@ fail:
    return NULL;
 }
 
+static uint8_t *
+alloc_shm(struct wsi_image *imagew, unsigned size)
+{
+#ifdef HAVE_SYS_SHM_H
+   struct x11_image *image = (struct x11_image *)imagew;
+   image->shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600);
+   if (image->shmid < 0)
+      return NULL;
+
+   uint8_t *addr = (uint8_t *)shmat(image->shmid, 0, 0);
+   /* mark the segment immediately for deletion to avoid leaks */
+   shmctl(image->shmid, IPC_RMID, 0);
+
+   if (addr == (uint8_t *) -1)
+      return NULL;
+
+   image->shmaddr = addr;
+   return addr;
+#else
+   return NULL;
+#endif
+}
+
 static VkResult
 x11_image_init(VkDevice device_h, struct x11_swapchain *chain,
                const VkSwapchainCreateInfoKHR *pCreateInfo,
@@ -1356,6 +1382,7 @@ x11_image_init(VkDevice device_h, struct x11_swapchain *chain,
    } else {
       result = wsi_create_native_image(&chain->base, pCreateInfo,
                                        num_tranches, num_modifiers, modifiers,
+                                       chain->has_mit_shm ? &alloc_shm : NULL,
                                        &image->base);
    }
    if (result < 0)
@@ -1463,6 +1490,10 @@ x11_image_finish(struct x11_swapchain *chain,
    }
 
    wsi_destroy_image(&chain->base, &image->base);
+#ifdef HAVE_SYS_SHM_H
+   if (image->shmaddr)
+      shmdt(image->shmaddr);
+#endif
 }
 
 static void