[PATCH] gnttab: Add gntdev device mappings for FreeBSD

* [PATCH] gnttab: Add gntdev device mappings for FreeBSD
@ 2016-08-04 12:53 Akshay Jaggi
  2016-08-05 16:45 ` Roger Pau Monné
  2016-08-11 16:14 ` Wei Liu
  0 siblings, 2 replies; 6+ messages in thread
From: Akshay Jaggi @ 2016-08-04 12:53 UTC (permalink / raw)
  To: xen-devel
  Cc: Stefano Stabellini, Wei Liu, George Dunlap, Andrew Cooper,
	royger, Ian Jackson, Tim Deegan, Jan Beulich, Akshay Jaggi

Add grant table userspace device mappings for
FreeBSD (enables support for qdisk backend
on FreeBSD Dom0).

Signed-off-by: Akshay Jaggi <akshay1994.leo@gmail.com>
---
 tools/include/xen-sys/FreeBSD/gntdev.h | 118 ++++++++++++
 tools/libs/gnttab/Makefile             |   2 +-
 tools/libs/gnttab/freebsd.c            | 335 +++++++++++++++++++++++++++++++++
 3 files changed, 454 insertions(+), 1 deletion(-)
 create mode 100644 tools/include/xen-sys/FreeBSD/gntdev.h
 create mode 100644 tools/libs/gnttab/freebsd.c

diff --git a/tools/include/xen-sys/FreeBSD/gntdev.h b/tools/include/xen-sys/FreeBSD/gntdev.h
new file mode 100644
index 0000000..1d09c5d
--- /dev/null
+++ b/tools/include/xen-sys/FreeBSD/gntdev.h
@@ -0,0 +1,118 @@
+/*-
+ * Copyright (c) 2016 Akshay Jaggi <jaggi@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * gntdev.h
+ * 
+ * Interface to /dev/xen/gntdev.
+ * 
+ */
+
+#ifndef __XEN_GNTDEV_H__
+#define __XEN_GNTDEV_H__
+
+#include <sys/types.h>
+
+#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY					\
+	_IOW('E', 0, struct ioctl_gntdev_unmap_notify)
+struct ioctl_gntdev_unmap_notify {
+    /* IN parameters */
+    uint64_t index;
+    uint32_t action;
+    uint32_t event_channel_port;
+};
+
+#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
+#define UNMAP_NOTIFY_SEND_EVENT 0x2
+
+/*-------------------- Grant Creation IOCTLs  --------------------------------*/
+
+#define IOCTL_GNTDEV_ALLOC_GREF						\
+	_IOWR('E', 1, struct ioctl_gntdev_alloc_gref)
+struct ioctl_gntdev_alloc_gref {
+    /* IN parameters */
+    uint16_t domid;
+    uint16_t flags;
+    uint32_t count;
+    /* OUT parameters */
+    uint64_t index;
+    /* Variable OUT parameter */
+    uint32_t gref_ids[1];
+};
+
+#define GNTDEV_ALLOC_FLAG_WRITABLE 1
+
+#define IOCTL_GNTDEV_DEALLOC_GREF					\
+	_IOW('E', 2, struct ioctl_gntdev_dealloc_gref)
+struct ioctl_gntdev_dealloc_gref {
+    /* IN parameters */
+    uint64_t index;
+    uint32_t count;
+};
+
+/*-------------------- Grant Accessing IOCTLs  -------------------------------*/
+
+struct ioctl_gntdev_grant_ref {
+    uint32_t domid;
+    uint32_t ref;
+};
+
+#define IOCTL_GNTDEV_MAP_GRANT_REF					\
+	_IOWR('E', 3, struct ioctl_gntdev_map_grant_ref)
+struct ioctl_gntdev_map_grant_ref {
+    /* IN parameters */
+    uint32_t count;
+    uint32_t pad0;
+    /* OUT parameters */
+    uint64_t index;
+    /* Variable IN parameter */
+    struct ioctl_gntdev_grant_ref refs[1];
+};
+
+#define IOCTL_GNTDEV_UNMAP_GRANT_REF					\
+	_IOW('E', 4, struct ioctl_gntdev_unmap_grant_ref)
+struct ioctl_gntdev_unmap_grant_ref {
+    /* IN parameters */
+    uint64_t index;
+    uint32_t count;
+};
+
+#define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR				\
+	_IOWR('E', 5, struct ioctl_gntdev_get_offset_for_vaddr)
+struct ioctl_gntdev_get_offset_for_vaddr {
+    /* IN parameters */
+    uint64_t vaddr;
+    /* OUT parameters */
+    uint64_t offset;
+    uint32_t count;
+};
+
+#define IOCTL_GNTDEV_SET_MAX_GRANTS					\
+	_IOW('E', 6, struct ioctl_gntdev_set_max_grants)
+struct ioctl_gntdev_set_max_grants {
+    /* IN parameters */
+    uint32_t count;
+};
+
+#endif /* __XEN_GNTDEV_H__ */
diff --git a/tools/libs/gnttab/Makefile b/tools/libs/gnttab/Makefile
index af64542..69bb207 100644
--- a/tools/libs/gnttab/Makefile
+++ b/tools/libs/gnttab/Makefile
@@ -14,7 +14,7 @@ SRCS-GNTSHR            += gntshr_core.c
 
 SRCS-$(CONFIG_Linux)   += $(SRCS-GNTTAB) $(SRCS-GNTSHR) linux.c
 SRCS-$(CONFIG_MiniOS)  += $(SRCS-GNTTAB) gntshr_unimp.c minios.c
-SRCS-$(CONFIG_FreeBSD) += gnttab_unimp.c gntshr_unimp.c
+SRCS-$(CONFIG_FreeBSD) += $(SRCS-GNTTAB) $(SRCS-GNTSHR) freebsd.c
 SRCS-$(CONFIG_SunOS)   += gnttab_unimp.c gntshr_unimp.c
 SRCS-$(CONFIG_NetBSD)  += gnttab_unimp.c gntshr_unimp.c
 
diff --git a/tools/libs/gnttab/freebsd.c b/tools/libs/gnttab/freebsd.c
new file mode 100644
index 0000000..eef0238
--- /dev/null
+++ b/tools/libs/gnttab/freebsd.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (c) 2007-2008, D G Murray <Derek.Murray@cl.cam.ac.uk>
+ * Copyright (c) 2016-2017, Akshay Jaggi <jaggi@FreeBSD.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Split out from linux.c
+ */
+
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <xen/sys/gntdev.h>
+
+#include "private.h"
+
+#define DEVXEN "/dev/xen/"
+
+#define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1))
+
+#define GTERROR(_l, _f...) xtl_log(_l, XTL_ERROR, errno, "gnttab", _f)
+#define GSERROR(_l, _f...) xtl_log(_l, XTL_ERROR, errno, "gntshr", _f)
+
+#define PAGE_SHIFT           12
+#define PAGE_SIZE            (1UL << PAGE_SHIFT)
+#define PAGE_MASK            (~(PAGE_SIZE-1))
+
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
+int osdep_gnttab_open(xengnttab_handle *xgt)
+{
+    int fd = open(DEVXEN "gntdev", O_RDWR|O_CLOEXEC);
+    if ( fd == -1 )
+        return -1;
+    xgt->fd = fd;
+    return 0;
+}
+
+int osdep_gnttab_close(xengnttab_handle *xgt)
+{
+    if ( xgt->fd == -1 )
+        return 0;
+
+    return close(xgt->fd);
+}
+
+int osdep_gnttab_set_max_grants(xengnttab_handle *xgt, uint32_t count)
+{
+    int fd = xgt->fd, rc;
+    struct ioctl_gntdev_set_max_grants max_grants = { .count = count };
+
+    rc = ioctl(fd, IOCTL_GNTDEV_SET_MAX_GRANTS, &max_grants);
+    if (rc) {
+        /*
+         * FreeBSD kernel doesn't implement this IOCTL,
+         * so ignore the resulting specific failure, if any.
+         */
+        if (errno == ENOTTY)
+            rc = 0;
+        else
+            GTERROR(xgt->logger, "ioctl SET_MAX_GRANTS failed");
+    }
+
+    return rc;
+}
+
+void *osdep_gnttab_grant_map(xengnttab_handle *xgt,
+                             uint32_t count, int flags, int prot,
+                             uint32_t *domids, uint32_t *refs,
+                             uint32_t notify_offset,
+                             evtchn_port_t notify_port)
+{
+    int fd = xgt->fd;
+    struct ioctl_gntdev_map_grant_ref *map;
+    unsigned int map_size = ROUNDUP((sizeof(*map) + (count - 1) *
+                                    sizeof(struct ioctl_gntdev_map_grant_ref)),
+                                    PAGE_SHIFT);
+    void *addr = NULL;
+    int domids_stride = 1;
+    int i;
+
+    if (flags & XENGNTTAB_GRANT_MAP_SINGLE_DOMAIN)
+        domids_stride = 0;
+
+    if ( map_size <= PAGE_SIZE )
+        map = alloca(sizeof(*map) +
+                     (count - 1) * sizeof(struct ioctl_gntdev_map_grant_ref));
+    else
+    {
+        map = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
+                   MAP_PRIVATE | MAP_ANON, -1, 0);
+        if ( map == MAP_FAILED )
+        {
+            GTERROR(xgt->logger, "mmap of map failed");
+            return NULL;
+        }
+    }
+
+    for ( i = 0; i < count; i++ )
+    {
+        map->refs[i].domid = domids[i * domids_stride];
+        map->refs[i].ref = refs[i];
+    }
+
+    map->count = count;
+
+    if ( ioctl(fd, IOCTL_GNTDEV_MAP_GRANT_REF, map) ) {
+        GTERROR(xgt->logger, "ioctl MAP_GRANT_REF failed");
+        goto out;
+    }
+
+ retry:
+    addr = mmap(NULL, PAGE_SIZE * count, prot, MAP_SHARED, fd,
+                map->index);
+
+    if (addr == MAP_FAILED && errno == EAGAIN)
+    {
+        /*
+         * The grant hypercall can return EAGAIN if the granted page
+         * is swapped out. Since the paging daemon may be in the same
+         * domain, the hypercall cannot block without causing a
+         * deadlock.
+         *
+         * Because there are no notifications when the page is swapped
+         * in, wait a bit before retrying, and hope that the page will
+         * arrive eventually.
+         */
+        usleep(1000);
+        goto retry;
+    }
+
+    if (addr != MAP_FAILED)
+    {
+        int rv = 0;
+        struct ioctl_gntdev_unmap_notify notify;
+        notify.index = map->index;
+        notify.action = 0;
+        if (notify_offset < PAGE_SIZE * count) {
+            notify.index += notify_offset;
+            notify.action |= UNMAP_NOTIFY_CLEAR_BYTE;
+        }
+        if (notify_port != -1) {
+            notify.event_channel_port = notify_port;
+            notify.action |= UNMAP_NOTIFY_SEND_EVENT;
+        }
+        if (notify.action)
+            rv = ioctl(fd, IOCTL_GNTDEV_SET_UNMAP_NOTIFY, &notify);
+        if (rv) {
+            GTERROR(xgt->logger, "ioctl SET_UNMAP_NOTIFY failed");
+            munmap(addr, count * PAGE_SIZE);
+            addr = MAP_FAILED;
+        }
+    }
+
+    if (addr == MAP_FAILED)
+    {
+        int saved_errno = errno;
+        struct ioctl_gntdev_unmap_grant_ref unmap_grant;
+
+        /* Unmap the driver slots used to store the grant information. */
+        GTERROR(xgt->logger, "mmap failed");
+        unmap_grant.index = map->index;
+        unmap_grant.count = count;
+        ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &unmap_grant);
+        errno = saved_errno;
+        addr = NULL;
+    }
+
+ out:
+    if ( map_size > PAGE_SIZE )
+        munmap(map, map_size);
+
+    return addr;
+}
+
+int osdep_gnttab_unmap(xengnttab_handle *xgt,
+                       void *start_address,
+                       uint32_t count)
+{
+    int fd = xgt->fd;
+    struct ioctl_gntdev_get_offset_for_vaddr get_offset;
+    struct ioctl_gntdev_unmap_grant_ref unmap_grant;
+    int rc;
+
+    if ( start_address == NULL )
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    /* First, it is necessary to get the offset which was initially used to
+     * mmap() the pages.
+     */
+    get_offset.vaddr = (unsigned long)start_address;
+    if ( (rc = ioctl(fd, IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR,
+                     &get_offset)) )
+        return rc;
+
+    if ( get_offset.count != count )
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    /* Next, unmap the memory. */
+    if ( (rc = munmap(start_address, count * PAGE_SIZE)) )
+        return rc;
+
+    /* Finally, unmap the driver slots used to store the grant information. */
+    unmap_grant.index = get_offset.offset;
+    unmap_grant.count = count;
+    if ( (rc = ioctl(fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &unmap_grant)) )
+        return rc;
+
+    return 0;
+}
+
+int osdep_gntshr_open(xengntshr_handle *xgs)
+{
+    int fd = open(DEVXEN "gntdev", O_RDWR);
+    if ( fd == -1 )
+        return -1;
+    xgs->fd = fd;
+    return 0;
+}
+
+int osdep_gntshr_close(xengntshr_handle *xgs)
+{
+    if ( xgs->fd == -1 )
+        return 0;
+
+    return close(xgs->fd);
+}
+
+void *osdep_gntshr_share_pages(xengntshr_handle *xgs,
+                               uint32_t domid, int count,
+                               uint32_t *refs, int writable,
+                               uint32_t notify_offset,
+                               evtchn_port_t notify_port)
+{
+    struct ioctl_gntdev_alloc_gref *gref_info = NULL;
+    struct ioctl_gntdev_unmap_notify notify;
+    struct ioctl_gntdev_dealloc_gref gref_drop;
+    int fd = xgs->fd;
+    int err;
+    void *area = NULL;
+    gref_info = malloc(sizeof(*gref_info) + count * sizeof(uint32_t));
+    if (!gref_info)
+        return NULL;
+    gref_info->domid = domid;
+    gref_info->flags = writable ? GNTDEV_ALLOC_FLAG_WRITABLE : 0;
+    gref_info->count = count;
+
+    err = ioctl(fd, IOCTL_GNTDEV_ALLOC_GREF, gref_info);
+    if (err) {
+        GSERROR(xgs->logger, "ioctl failed");
+        goto out;
+    }
+
+    area = mmap(NULL, count * PAGE_SIZE, PROT_READ | PROT_WRITE,
+        MAP_SHARED, fd, gref_info->index);
+
+    if (area == MAP_FAILED) {
+        area = NULL;
+        GSERROR(xgs->logger, "mmap failed");
+        goto out_remove_fdmap;
+    }
+
+    notify.index = gref_info->index;
+    notify.action = 0;
+    if (notify_offset < PAGE_SIZE * count) {
+        notify.index += notify_offset;
+        notify.action |= UNMAP_NOTIFY_CLEAR_BYTE;
+    }
+    if (notify_port != -1) {
+        notify.event_channel_port = notify_port;
+        notify.action |= UNMAP_NOTIFY_SEND_EVENT;
+    }
+    if (notify.action)
+        err = ioctl(fd, IOCTL_GNTDEV_SET_UNMAP_NOTIFY, &notify);
+    if (err) {
+        GSERROR(xgs->logger, "ioctl SET_UNMAP_NOTIFY failed");
+        munmap(area, count * PAGE_SIZE);
+        area = NULL;
+    }
+
+    memcpy(refs, gref_info->gref_ids, count * sizeof(uint32_t));
+
+ out_remove_fdmap:
+    /* Removing the mapping from the file descriptor does not cause the pages to
+     * be deallocated until the mapping is removed.
+     */
+    gref_drop.index = gref_info->index;
+    gref_drop.count = count;
+    ioctl(fd, IOCTL_GNTDEV_DEALLOC_GREF, &gref_drop);
+ out:
+    free(gref_info);
+    return area;
+}
+
+int osdep_gntshr_unshare(xengntshr_handle *xgs,
+                         void *start_address, uint32_t count)
+{
+    return munmap(start_address, count * PAGE_SIZE);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.8.2


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