drm/vmwgfx: Simplify devcaps code

Make devcaps code self-contained so that it's easier to cache
and operate on them.
As the number of devcaps got bigger the code dealing with them
got more and more tricky. Lets create a central place to deal
with all the complexity. This lets us remove the lock we used
to require to deal with register write races because we only
read the devcaps at initialization.
Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210609172307.131929-2-zackr@vmware.com

drivers/gpu/drm/vmwgfx/Makefile

@@ -9,7 +9,7 @@ vmwgfx-y := vmwgfx_execbuf.o vmwgfx_gmr.o vmwgfx_kms.o vmwgfx_drv.o \
 	    vmwgfx_cotable.o vmwgfx_so.o vmwgfx_binding.o vmwgfx_msg.o \
 	    vmwgfx_simple_resource.o vmwgfx_va.o vmwgfx_blit.o \
 	    vmwgfx_validation.o vmwgfx_page_dirty.o vmwgfx_streamoutput.o \
-	    ttm_object.o ttm_memory.o
+            vmwgfx_devcaps.o ttm_object.o ttm_memory.o
 
 vmwgfx-$(CONFIG_DRM_FBDEV_EMULATION) += vmwgfx_fb.o
 vmwgfx-$(CONFIG_TRANSPARENT_HUGEPAGE) += vmwgfx_thp.o

drivers/gpu/drm/vmwgfx/vmwgfx_cmd.c

@@ -30,6 +30,7 @@
 #include <drm/ttm/ttm_placement.h>
 
 #include "vmwgfx_drv.h"
+#include "vmwgfx_devcaps.h"
 
 bool vmw_supports_3d(struct vmw_private *dev_priv)
 {
@@ -45,10 +46,7 @@ bool vmw_supports_3d(struct vmw_private *dev_priv)
 		if (!dev_priv->has_mob)
 			return false;
 
-		spin_lock(&dev_priv->cap_lock);
-		vmw_write(dev_priv, SVGA_REG_DEV_CAP, SVGA3D_DEVCAP_3D);
-		result = vmw_read(dev_priv, SVGA_REG_DEV_CAP);
-		spin_unlock(&dev_priv->cap_lock);
+		result = vmw_devcap_get(dev_priv, SVGA3D_DEVCAP_3D);
 
 		return (result != 0);
 	}

drivers/gpu/drm/vmwgfx/vmwgfx_devcaps.c

+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/**************************************************************************
+ *
+ * Copyright 2021 VMware, Inc., Palo Alto, CA., USA
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "vmwgfx_devcaps.h"
+
+#include "vmwgfx_drv.h"
+
+
+struct svga_3d_compat_cap {
+	SVGA3dCapsRecordHeader header;
+	SVGA3dCapPair pairs[SVGA3D_DEVCAP_MAX];
+};
+
+
+static u32 vmw_mask_legacy_multisample(unsigned int cap, u32 fmt_value)
+{
+	/*
+	 * A version of user-space exists which use MULTISAMPLE_MASKABLESAMPLES
+	 * to check the sample count supported by virtual device. Since there
+	 * never was support for multisample count for backing MOB return 0.
+	 *
+	 * MULTISAMPLE_MASKABLESAMPLES devcap is marked as deprecated by virtual
+	 * device.
+	 */
+	if (cap == SVGA3D_DEVCAP_DEAD5)
+		return 0;
+
+	return fmt_value;
+}
+
+static int vmw_fill_compat_cap(struct vmw_private *dev_priv, void *bounce,
+			       size_t size)
+{
+	struct svga_3d_compat_cap *compat_cap =
+		(struct svga_3d_compat_cap *) bounce;
+	unsigned int i;
+	size_t pair_offset = offsetof(struct svga_3d_compat_cap, pairs);
+	unsigned int max_size;
+
+	if (size < pair_offset)
+		return -EINVAL;
+
+	max_size = (size - pair_offset) / sizeof(SVGA3dCapPair);
+
+	if (max_size > SVGA3D_DEVCAP_MAX)
+		max_size = SVGA3D_DEVCAP_MAX;
+
+	compat_cap->header.length =
+		(pair_offset + max_size * sizeof(SVGA3dCapPair)) / sizeof(u32);
+	compat_cap->header.type = SVGA3DCAPS_RECORD_DEVCAPS;
+
+	for (i = 0; i < max_size; ++i) {
+		compat_cap->pairs[i][0] = i;
+		compat_cap->pairs[i][1] = vmw_mask_legacy_multisample
+			(i, dev_priv->devcaps[i]);
+	}
+
+	return 0;
+}
+
+int vmw_devcaps_create(struct vmw_private *vmw)
+{
+	bool gb_objects = !!(vmw->capabilities & SVGA_CAP_GBOBJECTS);
+	uint32_t i;
+
+	if (gb_objects) {
+		vmw->devcaps = vzalloc(sizeof(uint32_t) * SVGA3D_DEVCAP_MAX);
+		if (!vmw->devcaps)
+			return -ENOMEM;
+		for (i = 0; i < SVGA3D_DEVCAP_MAX; ++i) {
+			vmw_write(vmw, SVGA_REG_DEV_CAP, i);
+			vmw->devcaps[i] = vmw_read(vmw, SVGA_REG_DEV_CAP);
+		}
+	}
+	return 0;
+}
+
+void vmw_devcaps_destroy(struct vmw_private *vmw)
+{
+	vfree(vmw->devcaps);
+	vmw->devcaps = NULL;
+}
+
+
+uint32 vmw_devcaps_size(const struct vmw_private *vmw,
+			bool gb_aware)
+{
+	bool gb_objects = !!(vmw->capabilities & SVGA_CAP_GBOBJECTS);
+	if (gb_objects && gb_aware)
+		return SVGA3D_DEVCAP_MAX * sizeof(uint32_t);
+	else if (gb_objects)
+		return  sizeof(struct svga_3d_compat_cap) +
+				sizeof(uint32_t);
+	else if (vmw->fifo_mem != NULL)
+		return (SVGA_FIFO_3D_CAPS_LAST - SVGA_FIFO_3D_CAPS + 1) *
+				sizeof(uint32_t);
+	else
+		return 0;
+}
+
+int vmw_devcaps_copy(struct vmw_private *vmw, bool gb_aware,
+		     void *dst, uint32_t dst_size)
+{
+	int ret;
+	bool gb_objects = !!(vmw->capabilities & SVGA_CAP_GBOBJECTS);
+	if (gb_objects && gb_aware) {
+		memcpy(dst, vmw->devcaps, dst_size);
+	} else if (gb_objects) {
+		ret = vmw_fill_compat_cap(vmw, dst, dst_size);
+		if (unlikely(ret != 0))
+			return ret;
+	} else if (vmw->fifo_mem) {
+		u32 *fifo_mem = vmw->fifo_mem;
+		memcpy(dst, &fifo_mem[SVGA_FIFO_3D_CAPS], dst_size);
+	} else
+		return -EINVAL;
+	return 0;
+}

drivers/gpu/drm/vmwgfx/vmwgfx_devcaps.h

+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/**************************************************************************
+ *
+ * Copyright 2021 VMware, Inc., Palo Alto, CA., USA
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#ifndef _VMWGFX_DEVCAPS_H_
+#define _VMWGFX_DEVCAPS_H_
+
+#include "vmwgfx_drv.h"
+
+#include "device_include/svga3d_caps.h"
+
+int vmw_devcaps_create(struct vmw_private *vmw);
+void vmw_devcaps_destroy(struct vmw_private *vmw);
+uint32_t vmw_devcaps_size(const struct vmw_private *vmw, bool gb_aware);
+int vmw_devcaps_copy(struct vmw_private *vmw, bool gb_aware,
+		     void *dst, uint32_t dst_size);
+
+static inline uint32_t vmw_devcap_get(struct vmw_private *vmw,
+				      uint32_t devcap)
+{
+	bool gb_objects = !!(vmw->capabilities & SVGA_CAP_GBOBJECTS);
+	if (gb_objects)
+		return vmw->devcaps[devcap];
+	return 0;
+}
+
+#endif

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -41,6 +41,7 @@
 
 #include "ttm_object.h"
 #include "vmwgfx_binding.h"
+#include "vmwgfx_devcaps.h"
 #include "vmwgfx_drv.h"
 
 #define VMWGFX_DRIVER_DESC "Linux drm driver for VMware graphics devices"
@@ -792,7 +793,6 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 	spin_lock_init(&dev_priv->resource_lock);
 	spin_lock_init(&dev_priv->hw_lock);
 	spin_lock_init(&dev_priv->waiter_lock);
-	spin_lock_init(&dev_priv->cap_lock);
 	spin_lock_init(&dev_priv->cursor_lock);
 
 	ret = vmw_setup_pci_resources(dev_priv, pci_id);
@@ -982,6 +982,12 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 		goto out_no_vram;
 	}
 
+	ret = vmw_devcaps_create(dev_priv);
+	if (unlikely(ret != 0)) {
+		DRM_ERROR("Failed initializing device caps.\n");
+		goto out_no_vram;
+	}
+
 	/*
 	 * "Guest Memory Regions" is an aperture like feature with
 	 *  one slot per bo. There is an upper limit of the number of
@@ -1008,11 +1014,8 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 	}
 
 	if (dev_priv->has_mob && (dev_priv->capabilities & SVGA_CAP_DX)) {
-		spin_lock(&dev_priv->cap_lock);
-		vmw_write(dev_priv, SVGA_REG_DEV_CAP, SVGA3D_DEVCAP_DXCONTEXT);
-		if (vmw_read(dev_priv, SVGA_REG_DEV_CAP))
+		if (vmw_devcap_get(dev_priv, SVGA3D_DEVCAP_DXCONTEXT))
 			dev_priv->sm_type = VMW_SM_4;
-		spin_unlock(&dev_priv->cap_lock);
 	}
 
 	vmw_validation_mem_init_ttm(dev_priv, VMWGFX_VALIDATION_MEM_GRAN);
@@ -1020,15 +1023,11 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 	/* SVGA_CAP2_DX2 (DefineGBSurface_v3) is needed for SM4_1 support */
 	if (has_sm4_context(dev_priv) &&
 	    (dev_priv->capabilities2 & SVGA_CAP2_DX2)) {
-		vmw_write(dev_priv, SVGA_REG_DEV_CAP, SVGA3D_DEVCAP_SM41);
-
-		if (vmw_read(dev_priv, SVGA_REG_DEV_CAP))
+		if (vmw_devcap_get(dev_priv, SVGA3D_DEVCAP_SM41))
 			dev_priv->sm_type = VMW_SM_4_1;
-
 		if (has_sm4_1_context(dev_priv) &&
-		    (dev_priv->capabilities2 & SVGA_CAP2_DX3)) {
-			vmw_write(dev_priv, SVGA_REG_DEV_CAP, SVGA3D_DEVCAP_SM5);
-			if (vmw_read(dev_priv, SVGA_REG_DEV_CAP))
+				(dev_priv->capabilities2 & SVGA_CAP2_DX3)) {
+			if (vmw_devcap_get(dev_priv, SVGA3D_DEVCAP_SM5))
 				dev_priv->sm_type = VMW_SM_5;
 		}
 	}
@@ -1073,6 +1072,7 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id)
 		vmw_gmrid_man_fini(dev_priv, VMW_PL_MOB);
 	if (dev_priv->has_gmr)
 		vmw_gmrid_man_fini(dev_priv, VMW_PL_GMR);
+	vmw_devcaps_destroy(dev_priv);
 	vmw_vram_manager_fini(dev_priv);
 out_no_vram:
 	ttm_device_fini(&dev_priv->bdev);
@@ -1121,6 +1121,7 @@ static void vmw_driver_unload(struct drm_device *dev)
 	vmw_release_device_early(dev_priv);
 	if (dev_priv->has_mob)
 		vmw_gmrid_man_fini(dev_priv, VMW_PL_MOB);
+	vmw_devcaps_destroy(dev_priv);
 	vmw_vram_manager_fini(dev_priv);
 	ttm_device_fini(&dev_priv->bdev);
 	drm_vma_offset_manager_destroy(&dev_priv->vma_manager);

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

@@ -513,7 +513,6 @@ struct vmw_private {
 	bool has_gmr;
 	bool has_mob;
 	spinlock_t hw_lock;
-	spinlock_t cap_lock;
 	bool assume_16bpp;
 
 	enum vmw_sm_type sm_type;
@@ -629,6 +628,8 @@ struct vmw_private {
 
 	/* Validation memory reservation */
 	struct vmw_validation_mem vvm;
+
+	uint32 *devcaps;
 };
 
 static inline struct vmw_surface *vmw_res_to_srf(struct vmw_resource *res)

drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c

@@ -26,14 +26,9 @@
  **************************************************************************/
 
 #include "vmwgfx_drv.h"
+#include "vmwgfx_devcaps.h"
 #include <drm/vmwgfx_drm.h>
 #include "vmwgfx_kms.h"
-#include "device_include/svga3d_caps.h"
-
-struct svga_3d_compat_cap {
-	SVGA3dCapsRecordHeader header;
-	SVGA3dCapPair pairs[SVGA3D_DEVCAP_MAX];
-};
 
 int vmw_getparam_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
@@ -88,16 +83,7 @@ int vmw_getparam_ioctl(struct drm_device *dev, void *data,
 			param->value = dev_priv->memory_size;
 		break;
 	case DRM_VMW_PARAM_3D_CAPS_SIZE:
-		if ((dev_priv->capabilities & SVGA_CAP_GBOBJECTS) &&
-		    vmw_fp->gb_aware)
-			param->value = SVGA3D_DEVCAP_MAX * sizeof(uint32_t);
-		else if (dev_priv->capabilities & SVGA_CAP_GBOBJECTS)
-			param->value = sizeof(struct svga_3d_compat_cap) +
-				sizeof(uint32_t);
-		else
-			param->value = (SVGA_FIFO_3D_CAPS_LAST -
-					SVGA_FIFO_3D_CAPS + 1) *
-				sizeof(uint32_t);
+		param->value = vmw_devcaps_size(dev_priv, vmw_fp->gb_aware);
 		break;
 	case DRM_VMW_PARAM_MAX_MOB_MEMORY:
 		vmw_fp->gb_aware = true;
@@ -126,55 +112,6 @@ int vmw_getparam_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
-static u32 vmw_mask_legacy_multisample(unsigned int cap, u32 fmt_value)
-{
-	/*
-	 * A version of user-space exists which use MULTISAMPLE_MASKABLESAMPLES
-	 * to check the sample count supported by virtual device. Since there
-	 * never was support for multisample count for backing MOB return 0.
-	 *
-	 * MULTISAMPLE_MASKABLESAMPLES devcap is marked as deprecated by virtual
-	 * device.
-	 */
-	if (cap == SVGA3D_DEVCAP_DEAD5)
-		return 0;
-
-	return fmt_value;
-}
-
-static int vmw_fill_compat_cap(struct vmw_private *dev_priv, void *bounce,
-			       size_t size)
-{
-	struct svga_3d_compat_cap *compat_cap =
-		(struct svga_3d_compat_cap *) bounce;
-	unsigned int i;
-	size_t pair_offset = offsetof(struct svga_3d_compat_cap, pairs);
-	unsigned int max_size;
-
-	if (size < pair_offset)
-		return -EINVAL;
-
-	max_size = (size - pair_offset) / sizeof(SVGA3dCapPair);
-
-	if (max_size > SVGA3D_DEVCAP_MAX)
-		max_size = SVGA3D_DEVCAP_MAX;
-
-	compat_cap->header.length =
-		(pair_offset + max_size * sizeof(SVGA3dCapPair)) / sizeof(u32);
-	compat_cap->header.type = SVGA3DCAPS_RECORD_DEVCAPS;
-
-	spin_lock(&dev_priv->cap_lock);
-	for (i = 0; i < max_size; ++i) {
-		vmw_write(dev_priv, SVGA_REG_DEV_CAP, i);
-		compat_cap->pairs[i][0] = i;
-		compat_cap->pairs[i][1] = vmw_mask_legacy_multisample
-			(i, vmw_read(dev_priv, SVGA_REG_DEV_CAP));
-	}
-	spin_unlock(&dev_priv->cap_lock);
-
-	return 0;
-}
-
 
 int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
@@ -183,11 +120,9 @@ int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
 		(struct drm_vmw_get_3d_cap_arg *) data;
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	uint32_t size;
-	u32 *fifo_mem;
 	void __user *buffer = (void __user *)((unsigned long)(arg->buffer));
-	void *bounce;
+	void *bounce = NULL;
 	int ret;
-	bool gb_objects = !!(dev_priv->capabilities & SVGA_CAP_GBOBJECTS);
 	struct vmw_fpriv *vmw_fp = vmw_fpriv(file_priv);
 
 	if (unlikely(arg->pad64 != 0 || arg->max_size == 0)) {
@@ -195,13 +130,11 @@ int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 
-	if (gb_objects && vmw_fp->gb_aware)
-		size = SVGA3D_DEVCAP_MAX * sizeof(uint32_t);
-	else if (gb_objects)
-		size = sizeof(struct svga_3d_compat_cap) + sizeof(uint32_t);
-	else
-		size = (SVGA_FIFO_3D_CAPS_LAST - SVGA_FIFO_3D_CAPS + 1) *
-			sizeof(uint32_t);
+	size = vmw_devcaps_size(dev_priv, vmw_fp->gb_aware);
+	if (unlikely(size == 0)) {
+		DRM_ERROR("Failed to figure out the devcaps size (no 3D).\n");
+		return -ENOMEM;
+	}
 
 	if (arg->max_size < size)
 		size = arg->max_size;
@@ -212,29 +145,9 @@ int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
 		return -ENOMEM;
 	}
 
-	if (gb_objects && vmw_fp->gb_aware) {
-		int i, num;
-		uint32_t *bounce32 = (uint32_t *) bounce;
-
-		num = size / sizeof(uint32_t);
-		if (num > SVGA3D_DEVCAP_MAX)
-			num = SVGA3D_DEVCAP_MAX;
-
-		spin_lock(&dev_priv->cap_lock);
-		for (i = 0; i < num; ++i) {
-			vmw_write(dev_priv, SVGA_REG_DEV_CAP, i);
-			*bounce32++ = vmw_mask_legacy_multisample
-				(i, vmw_read(dev_priv, SVGA_REG_DEV_CAP));
-		}
-		spin_unlock(&dev_priv->cap_lock);
-	} else if (gb_objects) {
-		ret = vmw_fill_compat_cap(dev_priv, bounce, size);
-		if (unlikely(ret != 0))
-			goto out_err;
-	} else {
-		fifo_mem = dev_priv->fifo_mem;
-		memcpy(bounce, &fifo_mem[SVGA_FIFO_3D_CAPS], size);
-	}
+	ret = vmw_devcaps_copy(dev_priv, vmw_fp->gb_aware, bounce, size);
+	if (unlikely (ret != 0))
+		goto out_err;
 
 	ret = copy_to_user(buffer, bounce, size);
 	if (ret)