* [PATCH v2] introduce grant copy for user land
@ 2014-12-02 16:13 Thanos Makatos
2014-12-05 18:05 ` Boris Ostrovsky
2014-12-08 11:02 ` David Vrabel
0 siblings, 2 replies; 4+ messages in thread
From: Thanos Makatos @ 2014-12-02 16:13 UTC (permalink / raw)
To: xen-devel; +Cc: boris.ostrovsky, david.vrabel, thanos.makatos
This patch introduces the interface to allow user-space applications
execute grant-copy operations. This is done by sending an ioctl to the
grant device.
Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
---
drivers/xen/gntdev.c | 171 +++++++++++++++++++++++++++++++++++++++++++++
include/uapi/xen/gntdev.h | 69 ++++++++++++++++++
2 files changed, 240 insertions(+)
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 51f4c95..7b4a8e0 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -705,6 +705,174 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
return rc;
}
+static int gntdev_gcopy_batch(int nr_segments, unsigned long gcopy_cb,
+ struct gntdev_grant_copy_segment __user *__segments, int dir,
+ int src, int dst) {
+
+ static const int batch_size = PAGE_SIZE / (sizeof(struct page*) +
+ sizeof(struct gnttab_copy) + sizeof(struct gntdev_grant_copy_segment));
+ struct page **pages = (struct page **)gcopy_cb;
+ struct gnttab_copy *batch = (struct gnttab_copy *)((unsigned long)pages +
+ sizeof(struct page*) * batch_size);
+ struct gntdev_grant_copy_segment *segments =
+ (struct gntdev_grant_copy_segment *)((unsigned long)batch +
+ sizeof(struct gnttab_copy) * batch_size);
+ unsigned int nr_pinned = 0, nr_segs2cp = 0;
+ int err = 0, i;
+ const int write = dir == GNTCOPY_IOCTL_g2s;
+
+ nr_segments = min(nr_segments, batch_size);
+
+ if (unlikely(copy_from_user(segments, __segments,
+ sizeof(struct gntdev_grant_copy_segment) * nr_segments))) {
+ pr_debug("failed to copy %d segments from user", nr_segments);
+ err = -EFAULT;
+ goto out;
+ }
+
+ for (i = 0; i < nr_segments; i++) {
+
+ xen_pfn_t pgaddr;
+ unsigned long start, offset;
+ struct gntdev_grant_copy_segment *seg = &segments[i];
+
+ if (dir == GNTCOPY_IOCTL_s2g || dir == GNTCOPY_IOCTL_g2s) {
+
+ start = (unsigned long)seg->self.iov.iov_base & PAGE_MASK;
+ offset = (unsigned long)seg->self.iov.iov_base & ~PAGE_MASK;
+ if (unlikely(offset + seg->self.iov.iov_len > PAGE_SIZE)) {
+ pr_warn("segments crossing page boundaries not yet "
+ "implemented\n");
+ err = -ENOSYS;
+ goto out;
+ }
+
+ err = get_user_pages_fast(start, 1, write, &pages[i]);
+ if (unlikely(err != 1)) {
+ pr_debug("failed to get user page %lu", start);
+ err = -EFAULT;
+ goto out;
+ }
+
+ nr_pinned++;
+
+ pgaddr = pfn_to_mfn(page_to_pfn(pages[i]));
+ }
+
+ nr_segs2cp++;
+
+ switch (dir) {
+ case GNTCOPY_IOCTL_g2s: /* copy from guest */
+ batch[i].len = seg->self.iov.iov_len;
+ batch[i].source.u.ref = seg->self.ref;
+ batch[i].source.domid = src;
+ batch[i].source.offset = seg->self.offset;
+ batch[i].dest.u.gmfn = pgaddr;
+ batch[i].dest.domid = DOMID_SELF;
+ batch[i].dest.offset = offset;
+ batch[i].flags = GNTCOPY_source_gref;
+ break;
+ case GNTCOPY_IOCTL_s2g: /* copy to guest */
+ batch[i].len = seg->self.iov.iov_len;
+ batch[i].source.u.gmfn = pgaddr;
+ batch[i].source.domid = DOMID_SELF;
+ batch[i].source.offset = offset;
+ batch[i].dest.u.ref = seg->self.ref;
+ batch[i].dest.domid = dst;
+ batch[i].dest.offset = seg->self.offset;
+ batch[i].flags = GNTCOPY_dest_gref;
+ break;
+ case GNTCOPY_IOCTL_g2g: /* copy guest to guest */
+ batch[i].len = seg->g2g.len;
+ batch[i].source.u.ref = seg->g2g.src.ref;
+ batch[i].source.domid = src;
+ batch[i].source.offset = seg->g2g.src.offset;
+ batch[i].dest.u.ref = seg->g2g.dst.ref;
+ batch[i].dest.domid = dst;
+ batch[i].dest.offset = seg->g2g.dst.offset;
+ batch[i].flags = GNTCOPY_source_gref | GNTCOPY_dest_gref;
+ break;
+ default:
+ pr_debug("invalid grant-copy direction %d\n", dir);
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+ gnttab_batch_copy(batch, nr_segs2cp);
+ for (i = 0; i < nr_segs2cp; i++) {
+ err = put_user(batch[i].status, &__segments[i].status);
+ if (unlikely(err)) {
+ pr_debug("failed to copy error code %d to user: %d\n",
+ batch[i].status, err);
+ goto out;
+ }
+ }
+
+out:
+ for (i = 0; i < nr_pinned; i++)
+ put_page(pages[i]);
+
+ if (unlikely(err))
+ return err;
+
+ return nr_segs2cp;
+}
+
+static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
+{
+ struct ioctl_gntdev_grant_copy op;
+ unsigned int remaining;
+ int err = 0;
+ unsigned long gcopy_cb = 0;
+
+ if (unlikely(copy_from_user(&op, u, sizeof(op)))) {
+ pr_debug("failed to copy grant-copy parameters from user");
+ err = -EFAULT;
+ goto out;
+ }
+
+ if (unlikely(op.dir != GNTCOPY_IOCTL_s2g && op.dir != GNTCOPY_IOCTL_g2s &&
+ op.dir != GNTCOPY_IOCTL_g2g)) {
+ pr_debug("invalid copy direction %d\n", op.dir);
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (!op.count) {
+ pr_debug("no segments to transfer");
+ err = 0;
+ goto out;
+ }
+
+ gcopy_cb = get_zeroed_page(GFP_KERNEL);
+ if (unlikely(!gcopy_cb)) {
+ pr_debug("failed to allocate page");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ remaining = op.count;
+
+ while (remaining > 0) {
+ err = gntdev_gcopy_batch(remaining, gcopy_cb,
+ op.segments + (op.count - remaining), op.dir, op.src, op.dst);
+ if (unlikely(err < 0)) {
+ pr_debug("failed to grant-copy %d segments: %d",
+ op.count - remaining, err);
+ goto out;
+ }
+ remaining -= err;
+ }
+
+ err = 0;
+
+out:
+ if (likely(gcopy_cb))
+ free_page(gcopy_cb);
+ return err;
+}
+
static long gntdev_ioctl(struct file *flip,
unsigned int cmd, unsigned long arg)
{
@@ -724,6 +892,9 @@ static long gntdev_ioctl(struct file *flip,
case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
return gntdev_ioctl_notify(priv, ptr);
+ case IOCTL_GNTDEV_GRANT_COPY:
+ return gntdev_ioctl_grant_copy(priv, ptr);
+
default:
pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
return -ENOIOCTLCMD;
diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h
index 5304bd3..17da5e9 100644
--- a/include/uapi/xen/gntdev.h
+++ b/include/uapi/xen/gntdev.h
@@ -33,6 +33,12 @@
#ifndef __LINUX_PUBLIC_GNTDEV_H__
#define __LINUX_PUBLIC_GNTDEV_H__
+#ifdef __KERNEL__
+#include <linux/uio.h>
+#else
+#include <sys/uio.h>
+#endif
+
struct ioctl_gntdev_grant_ref {
/* The domain ID of the grant to be mapped. */
uint32_t domid;
@@ -142,6 +148,69 @@ struct ioctl_gntdev_unmap_notify {
uint32_t event_channel_port;
};
+struct gntdev_grant_copy_segment {
+
+ union {
+ /* copy from (to) self to (from) guest */
+ struct {
+ /*
+ * source address and length
+ */
+ struct iovec iov;
+
+ /* the granted page */
+ uint32_t ref;
+
+ /* offset in the granted page */
+ uint16_t offset;
+ } self;
+
+ /* copy from guest to guest */
+ struct {
+ uint16_t len;
+
+ struct {
+ /* the granted page */
+ uint32_t ref;
+
+ /* offset in the granted page */
+ uint16_t offset;
+ } src, dst;
+ } g2g;
+ };
+
+ /* grant copy result (GNTST_XXX) */
+ int16_t status;
+};
+
+/* grant-copy from self to guest */
+#define GNTCOPY_IOCTL_s2g 0
+/* grant-copy from guest to self */
+#define GNTCOPY_IOCTL_g2s 1
+/* grant-copy from guest to guest */
+#define GNTCOPY_IOCTL_g2g 2
+
+#define IOCTL_GNTDEV_GRANT_COPY \
+_IOC(_IOC_NONE, 'G', 8, sizeof(struct ioctl_gntdev_grant_copy))
+struct ioctl_gntdev_grant_copy {
+ /*
+ * copy direction, see GNTCOPY_IOCTL_XXX
+ */
+ int dir;
+
+ /*
+ * domain IDs:
+ * When the source (destination) domain is the one executing the
+ * grant-copy operation, the @src (@dst) parameter is ignored.
+ */
+ uint32_t src;
+ uint32_t dst;
+
+ unsigned int count;
+
+ struct gntdev_grant_copy_segment __user *segments;
+};
+
/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
--
1.7.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] introduce grant copy for user land
2014-12-02 16:13 [PATCH v2] introduce grant copy for user land Thanos Makatos
@ 2014-12-05 18:05 ` Boris Ostrovsky
2014-12-09 12:34 ` Thanos Makatos
2014-12-08 11:02 ` David Vrabel
1 sibling, 1 reply; 4+ messages in thread
From: Boris Ostrovsky @ 2014-12-05 18:05 UTC (permalink / raw)
To: Thanos Makatos, xen-devel; +Cc: david.vrabel
On 12/02/2014 11:13 AM, Thanos Makatos wrote:
> This patch introduces the interface to allow user-space applications
> execute grant-copy operations. This is done by sending an ioctl to the
> grant device.
>
> Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
> ---
> drivers/xen/gntdev.c | 171 +++++++++++++++++++++++++++++++++++++++++++++
> include/uapi/xen/gntdev.h | 69 ++++++++++++++++++
> 2 files changed, 240 insertions(+)
>
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index 51f4c95..7b4a8e0 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -705,6 +705,174 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
> return rc;
> }
>
> +static int gntdev_gcopy_batch(int nr_segments, unsigned long gcopy_cb,
> + struct gntdev_grant_copy_segment __user *__segments, int dir,
> + int src, int dst) {
> +
> + static const int batch_size = PAGE_SIZE / (sizeof(struct page*) +
> + sizeof(struct gnttab_copy) + sizeof(struct gntdev_grant_copy_segment));
> + struct page **pages = (struct page **)gcopy_cb;
> + struct gnttab_copy *batch = (struct gnttab_copy *)((unsigned long)pages +
> + sizeof(struct page*) * batch_size);
> + struct gntdev_grant_copy_segment *segments =
> + (struct gntdev_grant_copy_segment *)((unsigned long)batch +
> + sizeof(struct gnttab_copy) * batch_size);
> + unsigned int nr_pinned = 0, nr_segs2cp = 0;
> + int err = 0, i;
> + const int write = dir == GNTCOPY_IOCTL_g2s;
> +
> + nr_segments = min(nr_segments, batch_size);
> +
> + if (unlikely(copy_from_user(segments, __segments,
> + sizeof(struct gntdev_grant_copy_segment) * nr_segments))) {
> + pr_debug("failed to copy %d segments from user", nr_segments);
> + err = -EFAULT;
> + goto out;
> + }
> +
> + for (i = 0; i < nr_segments; i++) {
> +
> + xen_pfn_t pgaddr;
> + unsigned long start, offset;
> + struct gntdev_grant_copy_segment *seg = &segments[i];
> +
> + if (dir == GNTCOPY_IOCTL_s2g || dir == GNTCOPY_IOCTL_g2s) {
> +
> + start = (unsigned long)seg->self.iov.iov_base & PAGE_MASK;
> + offset = (unsigned long)seg->self.iov.iov_base & ~PAGE_MASK;
> + if (unlikely(offset + seg->self.iov.iov_len > PAGE_SIZE)) {
> + pr_warn("segments crossing page boundaries not yet "
> + "implemented\n");
> + err = -ENOSYS;
> + goto out;
> + }
> +
> + err = get_user_pages_fast(start, 1, write, &pages[i]);
> + if (unlikely(err != 1)) {
> + pr_debug("failed to get user page %lu", start);
> + err = -EFAULT;
> + goto out;
> + }
> +
> + nr_pinned++;
> +
> + pgaddr = pfn_to_mfn(page_to_pfn(pages[i]));
> + }
> +
> + nr_segs2cp++;
> +
> + switch (dir) {
> + case GNTCOPY_IOCTL_g2s: /* copy from guest */
> + batch[i].len = seg->self.iov.iov_len;
> + batch[i].source.u.ref = seg->self.ref;
> + batch[i].source.domid = src;
> + batch[i].source.offset = seg->self.offset;
> + batch[i].dest.u.gmfn = pgaddr;
> + batch[i].dest.domid = DOMID_SELF;
> + batch[i].dest.offset = offset;
> + batch[i].flags = GNTCOPY_source_gref;
> + break;
> + case GNTCOPY_IOCTL_s2g: /* copy to guest */
> + batch[i].len = seg->self.iov.iov_len;
> + batch[i].source.u.gmfn = pgaddr;
> + batch[i].source.domid = DOMID_SELF;
> + batch[i].source.offset = offset;
> + batch[i].dest.u.ref = seg->self.ref;
> + batch[i].dest.domid = dst;
> + batch[i].dest.offset = seg->self.offset;
> + batch[i].flags = GNTCOPY_dest_gref;
> + break;
> + case GNTCOPY_IOCTL_g2g: /* copy guest to guest */
> + batch[i].len = seg->g2g.len;
> + batch[i].source.u.ref = seg->g2g.src.ref;
> + batch[i].source.domid = src;
> + batch[i].source.offset = seg->g2g.src.offset;
> + batch[i].dest.u.ref = seg->g2g.dst.ref;
> + batch[i].dest.domid = dst;
> + batch[i].dest.offset = seg->g2g.dst.offset;
> + batch[i].flags = GNTCOPY_source_gref | GNTCOPY_dest_gref;
> + break;
> + default:
> + pr_debug("invalid grant-copy direction %d\n", dir);
> + err = -EINVAL;
> + goto out;
> + }
> + }
> +
> + gnttab_batch_copy(batch, nr_segs2cp);
> + for (i = 0; i < nr_segs2cp; i++) {
Can nr_segs2cp be not equal to nr_segments here? If you got to this
point you have gone through the full loop.
> + err = put_user(batch[i].status, &__segments[i].status);
> + if (unlikely(err)) {
> + pr_debug("failed to copy error code %d to user: %d\n",
> + batch[i].status, err);
> + goto out;
> + }
> + }
> +
> +out:
> + for (i = 0; i < nr_pinned; i++)
> + put_page(pages[i]);
> +
> + if (unlikely(err))
> + return err;
> +
> + return nr_segs2cp;
And I think here it can be either 0 (which is the case of an error) or
nr_segments. If you error out of the 'for' loop you haven't actually
copied anything, even though nr_segs2cp might be non-zero.
-boris
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] introduce grant copy for user land
2014-12-05 18:05 ` Boris Ostrovsky
@ 2014-12-09 12:34 ` Thanos Makatos
0 siblings, 0 replies; 4+ messages in thread
From: Thanos Makatos @ 2014-12-09 12:34 UTC (permalink / raw)
To: 'Boris Ostrovsky', xen-devel@lists.xenproject.org; +Cc: David Vrabel
> -----Original Message-----
> From: Boris Ostrovsky [mailto:boris.ostrovsky@oracle.com]
> Sent: 05 December 2014 6:06 PM
> To: Thanos Makatos; xen-devel@lists.xenproject.org
> Cc: David Vrabel
> Subject: Re: [Xen-devel] [PATCH v2] introduce grant copy for user land
>
> On 12/02/2014 11:13 AM, Thanos Makatos wrote:
> > This patch introduces the interface to allow user-space applications
> > execute grant-copy operations. This is done by sending an ioctl to the
> > grant device.
> >
> > Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
> > ---
> > drivers/xen/gntdev.c | 171
> +++++++++++++++++++++++++++++++++++++++++++++
> > include/uapi/xen/gntdev.h | 69 ++++++++++++++++++
> > 2 files changed, 240 insertions(+)
> >
> > diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> > index 51f4c95..7b4a8e0 100644
> > --- a/drivers/xen/gntdev.c
> > +++ b/drivers/xen/gntdev.c
> > @@ -705,6 +705,174 @@ static long gntdev_ioctl_notify(struct gntdev_priv
> *priv, void __user *u)
> > return rc;
> > }
> >
> > +static int gntdev_gcopy_batch(int nr_segments, unsigned long gcopy_cb,
> > + struct gntdev_grant_copy_segment __user *__segments,
> int dir,
> > + int src, int dst) {
> > +
> > + static const int batch_size = PAGE_SIZE / (sizeof(struct page*) +
> > + sizeof(struct gnttab_copy) + sizeof(struct
> gntdev_grant_copy_segment));
> > + struct page **pages = (struct page **)gcopy_cb;
> > + struct gnttab_copy *batch = (struct gnttab_copy *)((unsigned
> long)pages +
> > + sizeof(struct page*) * batch_size);
> > + struct gntdev_grant_copy_segment *segments =
> > + (struct gntdev_grant_copy_segment *)((unsigned
> long)batch +
> > + sizeof(struct gnttab_copy) * batch_size);
> > + unsigned int nr_pinned = 0, nr_segs2cp = 0;
> > + int err = 0, i;
> > + const int write = dir == GNTCOPY_IOCTL_g2s;
> > +
> > + nr_segments = min(nr_segments, batch_size);
> > +
> > + if (unlikely(copy_from_user(segments, __segments,
> > + sizeof(struct gntdev_grant_copy_segment) *
> nr_segments))) {
> > + pr_debug("failed to copy %d segments from user",
> nr_segments);
> > + err = -EFAULT;
> > + goto out;
> > + }
> > +
> > + for (i = 0; i < nr_segments; i++) {
> > +
> > + xen_pfn_t pgaddr;
> > + unsigned long start, offset;
> > + struct gntdev_grant_copy_segment *seg = &segments[i];
> > +
> > + if (dir == GNTCOPY_IOCTL_s2g || dir ==
> GNTCOPY_IOCTL_g2s) {
> > +
> > + start = (unsigned long)seg->self.iov.iov_base &
> PAGE_MASK;
> > + offset = (unsigned long)seg->self.iov.iov_base &
> ~PAGE_MASK;
> > + if (unlikely(offset + seg->self.iov.iov_len >
> PAGE_SIZE)) {
> > + pr_warn("segments crossing page
> boundaries not yet "
> > + "implemented\n");
> > + err = -ENOSYS;
> > + goto out;
> > + }
> > +
> > + err = get_user_pages_fast(start, 1, write, &pages[i]);
> > + if (unlikely(err != 1)) {
> > + pr_debug("failed to get user page %lu",
> start);
> > + err = -EFAULT;
> > + goto out;
> > + }
> > +
> > + nr_pinned++;
> > +
> > + pgaddr = pfn_to_mfn(page_to_pfn(pages[i]));
> > + }
> > +
> > + nr_segs2cp++;
> > +
> > + switch (dir) {
> > + case GNTCOPY_IOCTL_g2s: /* copy from guest */
> > + batch[i].len = seg->self.iov.iov_len;
> > + batch[i].source.u.ref = seg->self.ref;
> > + batch[i].source.domid = src;
> > + batch[i].source.offset = seg->self.offset;
> > + batch[i].dest.u.gmfn = pgaddr;
> > + batch[i].dest.domid = DOMID_SELF;
> > + batch[i].dest.offset = offset;
> > + batch[i].flags = GNTCOPY_source_gref;
> > + break;
> > + case GNTCOPY_IOCTL_s2g: /* copy to guest */
> > + batch[i].len = seg->self.iov.iov_len;
> > + batch[i].source.u.gmfn = pgaddr;
> > + batch[i].source.domid = DOMID_SELF;
> > + batch[i].source.offset = offset;
> > + batch[i].dest.u.ref = seg->self.ref;
> > + batch[i].dest.domid = dst;
> > + batch[i].dest.offset = seg->self.offset;
> > + batch[i].flags = GNTCOPY_dest_gref;
> > + break;
> > + case GNTCOPY_IOCTL_g2g: /* copy guest to guest */
> > + batch[i].len = seg->g2g.len;
> > + batch[i].source.u.ref = seg->g2g.src.ref;
> > + batch[i].source.domid = src;
> > + batch[i].source.offset = seg->g2g.src.offset;
> > + batch[i].dest.u.ref = seg->g2g.dst.ref;
> > + batch[i].dest.domid = dst;
> > + batch[i].dest.offset = seg->g2g.dst.offset;
> > + batch[i].flags = GNTCOPY_source_gref |
> GNTCOPY_dest_gref;
> > + break;
> > + default:
> > + pr_debug("invalid grant-copy direction %d\n", dir);
> > + err = -EINVAL;
> > + goto out;
> > + }
> > + }
> > +
> > + gnttab_batch_copy(batch, nr_segs2cp);
> > + for (i = 0; i < nr_segs2cp; i++) {
>
> Can nr_segs2cp be not equal to nr_segments here? If you got to this
> point you have gone through the full loop.
Correct.
> > + err = put_user(batch[i].status, &__segments[i].status);
> > + if (unlikely(err)) {
> > + pr_debug("failed to copy error code %d to
> user: %d\n",
> > + batch[i].status, err);
> > + goto out;
> > + }
> > + }
> > +
> > +out:
> > + for (i = 0; i < nr_pinned; i++)
> > + put_page(pages[i]);
> > +
> > + if (unlikely(err))
> > + return err;
> > +
> > + return nr_segs2cp;
>
> And I think here it can be either 0 (which is the case of an error) or
> nr_segments. If you error out of the 'for' loop you haven't actually
> copied anything, even though nr_segs2cp might be non-zero.
If an error has occurred, "err" will be returned so the value of either "nr_segs2cp" or "nr_segments" is irrelevant. If no error occurs, then we have copied "nr_segments", therefore this is what we should return. I think I got something wrong and I thought there was some corner case so that why we needed an extra variable, but it doesn't seem to be the case. I'll replace "nr_segments" with "nr_segments".
> -boris
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] introduce grant copy for user land
2014-12-02 16:13 [PATCH v2] introduce grant copy for user land Thanos Makatos
2014-12-05 18:05 ` Boris Ostrovsky
@ 2014-12-08 11:02 ` David Vrabel
1 sibling, 0 replies; 4+ messages in thread
From: David Vrabel @ 2014-12-08 11:02 UTC (permalink / raw)
To: Thanos Makatos, xen-devel; +Cc: boris.ostrovsky, david.vrabel
On 02/12/14 16:13, Thanos Makatos wrote:
>
> +struct gntdev_grant_copy_segment {
> +
> + union {
> + /* copy from (to) self to (from) guest */
> + struct {
> + /*
> + * source address and length
> + */
> + struct iovec iov;
> +
> + /* the granted page */
> + uint32_t ref;
> +
> + /* offset in the granted page */
> + uint16_t offset;
> + } self;
> +
> + /* copy from guest to guest */
> + struct {
> + uint16_t len;
> +
> + struct {
> + /* the granted page */
> + uint32_t ref;
> +
> + /* offset in the granted page */
> + uint16_t offset;
> + } src, dst;
> + } g2g;
> + };
> +
> + /* grant copy result (GNTST_XXX) */
> + int16_t status;
> +};
I asked for this ioctl to mirror the hypercall.
Which looks like:
struct gnttab_copy {
/* IN parameters. */
struct {
union {
grant_ref_t ref;
xen_pfn_t gmfn;
} u;
domid_t domid;
uint16_t offset;
} source, dest;
uint16_t len;
uint16_t flags; /* GNTCOPY_* */
/* OUT parameters. */
int16_t status;
};
i.e., each operation specifies the domid of the source and destination
and whether it includes a ref or a virtual address.
David
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2014-12-02 16:13 [PATCH v2] introduce grant copy for user land Thanos Makatos
2014-12-05 18:05 ` Boris Ostrovsky
2014-12-09 12:34 ` Thanos Makatos
2014-12-08 11:02 ` David Vrabel
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