Commit 5641f19b authored by Oleksandr Andrushchenko's avatar Oleksandr Andrushchenko Committed by Boris Ostrovsky
Browse files

drm/xen-front: Use Xen common shared buffer implementation 



Use page directory based shared buffer implementation
now available as common code for Xen frontend drivers.

Remove flushing of shared buffer on page flip as this
workaround needs a proper fix.

Signed-off-by: default avatarOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent b3383974

drivers/gpu/drm/xen/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ config DRM_XEN_FRONTEND 
	select DRM_KMS_HELPER

	select VIDEOMODE_HELPERS

	select XEN_XENBUS_FRONTEND

	select XEN_FRONT_PGDIR_SHBUF

	help

	  Choose this option if you want to enable a para-virtualized

	  frontend DRM/KMS driver for Xen guest OSes.

drivers/gpu/drm/xen/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -4,7 +4,6 @@ drm_xen_front-objs := xen_drm_front.o \ 
		      xen_drm_front_kms.o \

		      xen_drm_front_conn.o \

		      xen_drm_front_evtchnl.o \

		      xen_drm_front_shbuf.o \

		      xen_drm_front_cfg.o \

		      xen_drm_front_gem.o

drivers/gpu/drm/xen/xen_drm_front.c

+25 −40
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <xen/xen.h>

#include <xen/xenbus.h>



#include <xen/xen-front-pgdir-shbuf.h>

#include <xen/interface/io/displif.h>



#include "xen_drm_front.h"
@@ -26,28 +27,20 @@ 
#include "xen_drm_front_evtchnl.h"

#include "xen_drm_front_gem.h"

#include "xen_drm_front_kms.h"

#include "xen_drm_front_shbuf.h"



struct xen_drm_front_dbuf {

	struct list_head list;

	u64 dbuf_cookie;

	u64 fb_cookie;

	struct xen_drm_front_shbuf *shbuf;



	struct xen_front_pgdir_shbuf shbuf;

};



static int dbuf_add_to_list(struct xen_drm_front_info *front_info,

			    struct xen_drm_front_shbuf *shbuf, u64 dbuf_cookie)

static void dbuf_add_to_list(struct xen_drm_front_info *front_info,

			     struct xen_drm_front_dbuf *dbuf, u64 dbuf_cookie)

{

	struct xen_drm_front_dbuf *dbuf;



	dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL);

	if (!dbuf)

		return -ENOMEM;



	dbuf->dbuf_cookie = dbuf_cookie;

	dbuf->shbuf = shbuf;

	list_add(&dbuf->list, &front_info->dbuf_list);

	return 0;

}



static struct xen_drm_front_dbuf *dbuf_get(struct list_head *dbuf_list,
@@ -62,15 +55,6 @@ static struct xen_drm_front_dbuf *dbuf_get(struct list_head *dbuf_list, 
	return NULL;

}



static void dbuf_flush_fb(struct list_head *dbuf_list, u64 fb_cookie)

{

	struct xen_drm_front_dbuf *buf, *q;



	list_for_each_entry_safe(buf, q, dbuf_list, list)

		if (buf->fb_cookie == fb_cookie)

			xen_drm_front_shbuf_flush(buf->shbuf);

}



static void dbuf_free(struct list_head *dbuf_list, u64 dbuf_cookie)

{

	struct xen_drm_front_dbuf *buf, *q;
@@ -78,8 +62,8 @@ static void dbuf_free(struct list_head *dbuf_list, u64 dbuf_cookie) 
	list_for_each_entry_safe(buf, q, dbuf_list, list)

		if (buf->dbuf_cookie == dbuf_cookie) {

			list_del(&buf->list);

			xen_drm_front_shbuf_unmap(buf->shbuf);

			xen_drm_front_shbuf_free(buf->shbuf);

			xen_front_pgdir_shbuf_unmap(&buf->shbuf);

			xen_front_pgdir_shbuf_free(&buf->shbuf);

			kfree(buf);

			break;

		}
@@ -91,8 +75,8 @@ static void dbuf_free_all(struct list_head *dbuf_list) 


	list_for_each_entry_safe(buf, q, dbuf_list, list) {

		list_del(&buf->list);

		xen_drm_front_shbuf_unmap(buf->shbuf);

		xen_drm_front_shbuf_free(buf->shbuf);

		xen_front_pgdir_shbuf_unmap(&buf->shbuf);

		xen_front_pgdir_shbuf_free(&buf->shbuf);

		kfree(buf);

	}

}
@@ -171,9 +155,9 @@ int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info, 
			      u32 bpp, u64 size, struct page **pages)

{

	struct xen_drm_front_evtchnl *evtchnl;

	struct xen_drm_front_shbuf *shbuf;

	struct xen_drm_front_dbuf *dbuf;

	struct xendispl_req *req;

	struct xen_drm_front_shbuf_cfg buf_cfg;

	struct xen_front_pgdir_shbuf_cfg buf_cfg;

	unsigned long flags;

	int ret;
@@ -181,28 +165,29 @@ int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info, 
	if (unlikely(!evtchnl))

		return -EIO;



	dbuf = kzalloc(sizeof(*dbuf), GFP_KERNEL);

	if (!dbuf)

		return -ENOMEM;



	dbuf_add_to_list(front_info, dbuf, dbuf_cookie);



	memset(&buf_cfg, 0, sizeof(buf_cfg));

	buf_cfg.xb_dev = front_info->xb_dev;

	buf_cfg.num_pages = DIV_ROUND_UP(size, PAGE_SIZE);

	buf_cfg.pages = pages;

	buf_cfg.size = size;

	buf_cfg.pgdir = &dbuf->shbuf;

	buf_cfg.be_alloc = front_info->cfg.be_alloc;



	shbuf = xen_drm_front_shbuf_alloc(&buf_cfg);

	if (IS_ERR(shbuf))

		return PTR_ERR(shbuf);



	ret = dbuf_add_to_list(front_info, shbuf, dbuf_cookie);

	if (ret < 0) {

		xen_drm_front_shbuf_free(shbuf);

		return ret;

	}

	ret = xen_front_pgdir_shbuf_alloc(&buf_cfg);

	if (ret < 0)

		goto fail_shbuf_alloc;



	mutex_lock(&evtchnl->u.req.req_io_lock);



	spin_lock_irqsave(&front_info->io_lock, flags);

	req = be_prepare_req(evtchnl, XENDISPL_OP_DBUF_CREATE);

	req->op.dbuf_create.gref_directory =

			xen_drm_front_shbuf_get_dir_start(shbuf);

			xen_front_pgdir_shbuf_get_dir_start(&dbuf->shbuf);

	req->op.dbuf_create.buffer_sz = size;

	req->op.dbuf_create.dbuf_cookie = dbuf_cookie;

	req->op.dbuf_create.width = width;
@@ -221,7 +206,7 @@ int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info, 
	if (ret < 0)

		goto fail;



	ret = xen_drm_front_shbuf_map(shbuf);

	ret = xen_front_pgdir_shbuf_map(&dbuf->shbuf);

	if (ret < 0)

		goto fail;
@@ -230,6 +215,7 @@ int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info, 


fail:

	mutex_unlock(&evtchnl->u.req.req_io_lock);

fail_shbuf_alloc:

	dbuf_free(&front_info->dbuf_list, dbuf_cookie);

	return ret;

}
@@ -358,7 +344,6 @@ int xen_drm_front_page_flip(struct xen_drm_front_info *front_info, 
	if (unlikely(conn_idx >= front_info->num_evt_pairs))

		return -EINVAL;



	dbuf_flush_fb(&front_info->dbuf_list, fb_cookie);

	evtchnl = &front_info->evt_pairs[conn_idx].req;



	mutex_lock(&evtchnl->u.req.req_io_lock);

drivers/gpu/drm/xen/xen_drm_front_gem.c

+0 −1
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ 
#include <xen/balloon.h>



#include "xen_drm_front.h"

#include "xen_drm_front_shbuf.h"



struct xen_gem_object {

	struct drm_gem_object base;

drivers/gpu/drm/xen/xen_drm_front_shbuf.c

deleted100644 → 0
+0 −414
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0 OR MIT



/*

 *  Xen para-virtual DRM device

 *

 * Copyright (C) 2016-2018 EPAM Systems Inc.

 *

 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

 */



#include <drm/drmP.h>



#if defined(CONFIG_X86)

#include <drm/drm_cache.h>

#endif

#include <linux/errno.h>

#include <linux/mm.h>



#include <asm/xen/hypervisor.h>

#include <xen/balloon.h>

#include <xen/xen.h>

#include <xen/xenbus.h>

#include <xen/interface/io/ring.h>

#include <xen/interface/io/displif.h>



#include "xen_drm_front.h"

#include "xen_drm_front_shbuf.h"



struct xen_drm_front_shbuf_ops {

	/*

	 * Calculate number of grefs required to handle this buffer,

	 * e.g. if grefs are required for page directory only or the buffer

	 * pages as well.

	 */

	void (*calc_num_grefs)(struct xen_drm_front_shbuf *buf);

	/* Fill page directory according to para-virtual display protocol. */

	void (*fill_page_dir)(struct xen_drm_front_shbuf *buf);

	/* Claim grant references for the pages of the buffer. */

	int (*grant_refs_for_buffer)(struct xen_drm_front_shbuf *buf,

				     grant_ref_t *priv_gref_head, int gref_idx);

	/* Map grant references of the buffer. */

	int (*map)(struct xen_drm_front_shbuf *buf);

	/* Unmap grant references of the buffer. */

	int (*unmap)(struct xen_drm_front_shbuf *buf);

};



grant_ref_t xen_drm_front_shbuf_get_dir_start(struct xen_drm_front_shbuf *buf)

{

	if (!buf->grefs)

		return GRANT_INVALID_REF;



	return buf->grefs[0];

}



int xen_drm_front_shbuf_map(struct xen_drm_front_shbuf *buf)

{

	if (buf->ops->map)

		return buf->ops->map(buf);



	/* no need to map own grant references */

	return 0;

}



int xen_drm_front_shbuf_unmap(struct xen_drm_front_shbuf *buf)

{

	if (buf->ops->unmap)

		return buf->ops->unmap(buf);



	/* no need to unmap own grant references */

	return 0;

}



void xen_drm_front_shbuf_flush(struct xen_drm_front_shbuf *buf)

{

#if defined(CONFIG_X86)

	drm_clflush_pages(buf->pages, buf->num_pages);

#endif

}



void xen_drm_front_shbuf_free(struct xen_drm_front_shbuf *buf)

{

	if (buf->grefs) {

		int i;



		for (i = 0; i < buf->num_grefs; i++)

			if (buf->grefs[i] != GRANT_INVALID_REF)

				gnttab_end_foreign_access(buf->grefs[i],

							  0, 0UL);

	}

	kfree(buf->grefs);

	kfree(buf->directory);

	kfree(buf);

}



/*

 * number of grefs a page can hold with respect to the

 * struct xendispl_page_directory header

 */

#define XEN_DRM_NUM_GREFS_PER_PAGE ((PAGE_SIZE - \

		offsetof(struct xendispl_page_directory, gref)) / \

		sizeof(grant_ref_t))



static int get_num_pages_dir(struct xen_drm_front_shbuf *buf)

{

	/* number of pages the page directory consumes itself */

	return DIV_ROUND_UP(buf->num_pages, XEN_DRM_NUM_GREFS_PER_PAGE);

}



static void backend_calc_num_grefs(struct xen_drm_front_shbuf *buf)

{

	/* only for pages the page directory consumes itself */

	buf->num_grefs = get_num_pages_dir(buf);

}



static void guest_calc_num_grefs(struct xen_drm_front_shbuf *buf)

{

	/*

	 * number of pages the page directory consumes itself

	 * plus grefs for the buffer pages

	 */

	buf->num_grefs = get_num_pages_dir(buf) + buf->num_pages;

}



#define xen_page_to_vaddr(page) \

		((uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page)))



static int backend_unmap(struct xen_drm_front_shbuf *buf)

{

	struct gnttab_unmap_grant_ref *unmap_ops;

	int i, ret;



	if (!buf->pages || !buf->backend_map_handles || !buf->grefs)

		return 0;



	unmap_ops = kcalloc(buf->num_pages, sizeof(*unmap_ops),

			    GFP_KERNEL);

	if (!unmap_ops) {

		DRM_ERROR("Failed to get memory while unmapping\n");

		return -ENOMEM;

	}



	for (i = 0; i < buf->num_pages; i++) {

		phys_addr_t addr;



		addr = xen_page_to_vaddr(buf->pages[i]);

		gnttab_set_unmap_op(&unmap_ops[i], addr, GNTMAP_host_map,

				    buf->backend_map_handles[i]);

	}



	ret = gnttab_unmap_refs(unmap_ops, NULL, buf->pages,

				buf->num_pages);



	for (i = 0; i < buf->num_pages; i++) {

		if (unlikely(unmap_ops[i].status != GNTST_okay))

			DRM_ERROR("Failed to unmap page %d: %d\n",

				  i, unmap_ops[i].status);

	}



	if (ret)

		DRM_ERROR("Failed to unmap grant references, ret %d", ret);



	kfree(unmap_ops);

	kfree(buf->backend_map_handles);

	buf->backend_map_handles = NULL;

	return ret;

}



static int backend_map(struct xen_drm_front_shbuf *buf)

{

	struct gnttab_map_grant_ref *map_ops = NULL;

	unsigned char *ptr;

	int ret, cur_gref, cur_dir_page, cur_page, grefs_left;



	map_ops = kcalloc(buf->num_pages, sizeof(*map_ops), GFP_KERNEL);

	if (!map_ops)

		return -ENOMEM;



	buf->backend_map_handles = kcalloc(buf->num_pages,

					   sizeof(*buf->backend_map_handles),

					   GFP_KERNEL);

	if (!buf->backend_map_handles) {

		kfree(map_ops);

		return -ENOMEM;

	}



	/*

	 * read page directory to get grefs from the backend: for external

	 * buffer we only allocate buf->grefs for the page directory,

	 * so buf->num_grefs has number of pages in the page directory itself

	 */

	ptr = buf->directory;

	grefs_left = buf->num_pages;

	cur_page = 0;

	for (cur_dir_page = 0; cur_dir_page < buf->num_grefs; cur_dir_page++) {

		struct xendispl_page_directory *page_dir =

				(struct xendispl_page_directory *)ptr;

		int to_copy = XEN_DRM_NUM_GREFS_PER_PAGE;



		if (to_copy > grefs_left)

			to_copy = grefs_left;



		for (cur_gref = 0; cur_gref < to_copy; cur_gref++) {

			phys_addr_t addr;



			addr = xen_page_to_vaddr(buf->pages[cur_page]);

			gnttab_set_map_op(&map_ops[cur_page], addr,

					  GNTMAP_host_map,

					  page_dir->gref[cur_gref],

					  buf->xb_dev->otherend_id);

			cur_page++;

		}



		grefs_left -= to_copy;

		ptr += PAGE_SIZE;

	}

	ret = gnttab_map_refs(map_ops, NULL, buf->pages, buf->num_pages);



	/* save handles even if error, so we can unmap */

	for (cur_page = 0; cur_page < buf->num_pages; cur_page++) {

		buf->backend_map_handles[cur_page] = map_ops[cur_page].handle;

		if (unlikely(map_ops[cur_page].status != GNTST_okay))

			DRM_ERROR("Failed to map page %d: %d\n",

				  cur_page, map_ops[cur_page].status);

	}



	if (ret) {

		DRM_ERROR("Failed to map grant references, ret %d", ret);

		backend_unmap(buf);

	}



	kfree(map_ops);

	return ret;

}



static void backend_fill_page_dir(struct xen_drm_front_shbuf *buf)

{

	struct xendispl_page_directory *page_dir;

	unsigned char *ptr;

	int i, num_pages_dir;



	ptr = buf->directory;

	num_pages_dir = get_num_pages_dir(buf);



	/* fill only grefs for the page directory itself */

	for (i = 0; i < num_pages_dir - 1; i++) {

		page_dir = (struct xendispl_page_directory *)ptr;



		page_dir->gref_dir_next_page = buf->grefs[i + 1];

		ptr += PAGE_SIZE;

	}

	/* last page must say there is no more pages */

	page_dir = (struct xendispl_page_directory *)ptr;

	page_dir->gref_dir_next_page = GRANT_INVALID_REF;

}



static void guest_fill_page_dir(struct xen_drm_front_shbuf *buf)

{

	unsigned char *ptr;

	int cur_gref, grefs_left, to_copy, i, num_pages_dir;



	ptr = buf->directory;

	num_pages_dir = get_num_pages_dir(buf);



	/*

	 * while copying, skip grefs at start, they are for pages

	 * granted for the page directory itself

	 */

	cur_gref = num_pages_dir;

	grefs_left = buf->num_pages;

	for (i = 0; i < num_pages_dir; i++) {

		struct xendispl_page_directory *page_dir =

				(struct xendispl_page_directory *)ptr;



		if (grefs_left <= XEN_DRM_NUM_GREFS_PER_PAGE) {

			to_copy = grefs_left;

			page_dir->gref_dir_next_page = GRANT_INVALID_REF;

		} else {

			to_copy = XEN_DRM_NUM_GREFS_PER_PAGE;

			page_dir->gref_dir_next_page = buf->grefs[i + 1];

		}

		memcpy(&page_dir->gref, &buf->grefs[cur_gref],

		       to_copy * sizeof(grant_ref_t));

		ptr += PAGE_SIZE;

		grefs_left -= to_copy;

		cur_gref += to_copy;

	}

}



static int guest_grant_refs_for_buffer(struct xen_drm_front_shbuf *buf,

				       grant_ref_t *priv_gref_head,

				       int gref_idx)

{

	int i, cur_ref, otherend_id;



	otherend_id = buf->xb_dev->otherend_id;

	for (i = 0; i < buf->num_pages; i++) {

		cur_ref = gnttab_claim_grant_reference(priv_gref_head);

		if (cur_ref < 0)

			return cur_ref;



		gnttab_grant_foreign_access_ref(cur_ref, otherend_id,

						xen_page_to_gfn(buf->pages[i]),

						0);

		buf->grefs[gref_idx++] = cur_ref;

	}

	return 0;

}



static int grant_references(struct xen_drm_front_shbuf *buf)

{

	grant_ref_t priv_gref_head;

	int ret, i, j, cur_ref;

	int otherend_id, num_pages_dir;



	ret = gnttab_alloc_grant_references(buf->num_grefs, &priv_gref_head);

	if (ret < 0) {

		DRM_ERROR("Cannot allocate grant references\n");

		return ret;

	}



	otherend_id = buf->xb_dev->otherend_id;

	j = 0;

	num_pages_dir = get_num_pages_dir(buf);

	for (i = 0; i < num_pages_dir; i++) {

		unsigned long frame;



		cur_ref = gnttab_claim_grant_reference(&priv_gref_head);

		if (cur_ref < 0)

			return cur_ref;



		frame = xen_page_to_gfn(virt_to_page(buf->directory +

					PAGE_SIZE * i));

		gnttab_grant_foreign_access_ref(cur_ref, otherend_id, frame, 0);

		buf->grefs[j++] = cur_ref;

	}



	if (buf->ops->grant_refs_for_buffer) {

		ret = buf->ops->grant_refs_for_buffer(buf, &priv_gref_head, j);

		if (ret)

			return ret;

	}



	gnttab_free_grant_references(priv_gref_head);

	return 0;

}



static int alloc_storage(struct xen_drm_front_shbuf *buf)

{

	buf->grefs = kcalloc(buf->num_grefs, sizeof(*buf->grefs), GFP_KERNEL);

	if (!buf->grefs)

		return -ENOMEM;



	buf->directory = kcalloc(get_num_pages_dir(buf), PAGE_SIZE, GFP_KERNEL);

	if (!buf->directory)

		return -ENOMEM;



	return 0;

}



/*

 * For be allocated buffers we don't need grant_refs_for_buffer as those

 * grant references are allocated at backend side

 */

static const struct xen_drm_front_shbuf_ops backend_ops = {

	.calc_num_grefs = backend_calc_num_grefs,

	.fill_page_dir = backend_fill_page_dir,

	.map = backend_map,

	.unmap = backend_unmap

};



/* For locally granted references we do not need to map/unmap the references */

static const struct xen_drm_front_shbuf_ops local_ops = {

	.calc_num_grefs = guest_calc_num_grefs,

	.fill_page_dir = guest_fill_page_dir,

	.grant_refs_for_buffer = guest_grant_refs_for_buffer,

};



struct xen_drm_front_shbuf *

xen_drm_front_shbuf_alloc(struct xen_drm_front_shbuf_cfg *cfg)

{

	struct xen_drm_front_shbuf *buf;

	int ret;



	buf = kzalloc(sizeof(*buf), GFP_KERNEL);

	if (!buf)

		return ERR_PTR(-ENOMEM);



	if (cfg->be_alloc)

		buf->ops = &backend_ops;

	else

		buf->ops = &local_ops;



	buf->xb_dev = cfg->xb_dev;

	buf->num_pages = DIV_ROUND_UP(cfg->size, PAGE_SIZE);

	buf->pages = cfg->pages;



	buf->ops->calc_num_grefs(buf);



	ret = alloc_storage(buf);

	if (ret)

		goto fail;



	ret = grant_references(buf);

	if (ret)

		goto fail;



	buf->ops->fill_page_dir(buf);



	return buf;



fail:

	xen_drm_front_shbuf_free(buf);

	return ERR_PTR(ret);

}

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