Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On Tue, Aug 09, 2016 at 07:34:14PM +0200, Paulina Szubarczyk wrote:
> On 08/09/2016 06:56 PM, Anthony PERARD wrote:
> > On Tue, Aug 02, 2016 at 04:06:30PM +0200, Paulina Szubarczyk wrote:
> > > diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
> > > index 640c31e..e80c61f 100644
> > > --- a/include/hw/xen/xen_common.h
> > > +++ b/include/hw/xen/xen_common.h
> > > @@ -25,6 +25,31 @@
> > >*/
> > >
> > > /* Xen 4.2 through 4.6 */
> > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 480
> > > +
> > > +struct xengnttab_grant_copy_segment {
> > > +union xengnttab_copy_ptr {
> > > +void *virt;
> > > +struct {
> > > +uint32_t ref;
> > > +uint16_t offset;
> > > +uint16_t domid;
> > > +} foreign;
> > > +} source, dest;
> > > +uint16_t len;
> > > +uint16_t flags;
> > > +int16_t status;
> > > +};
> >
> > I don't think it's a good idee to define a struct that is not going to
> > be used, and does not belong here. The typedef is OK.
>
> I added it since it is needed to know all the fields of that struct in
> ioreq_copy but if I could replace that function with stubs I will do that.
>
> >
> > In xen_disk.c, you could use "#if CONFIG_XEN_CTRL_INTERFACE_VERSION ..."
> > around free_buffers, ioreq_init_copy_buffers and ioreq_copy, and replace
> > them by stubs when Xen does not support grant copy. I think that would
> > be better.
> >
> > Also, could you try to compile again xen unstable, without your other patch?
> > Right now, it does not compile.
>
> That is true, I am sorry. I need to add the headers that are included in the
> #else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 471 */
>
> #include
> #include
> #include
>
> #endif
>
> May I move that part to separate #if CONFIG_XEN_CTRL_INTERFACE_VERSION >=
> 471 in that header?
You could could add your code at the end of xen_common.h instead of the
beginning, I think that would work. (At the end of xen_common.h,
xengnttab_handle should be define, either in the file or via an
include.)
> >
> > > +typedef struct xengnttab_grant_copy_segment
> > > xengnttab_grant_copy_segment_t;
> > > +
> > > +static inline int xengnttab_grant_copy(xengnttab_handle *xgt, uint32_t
> > > count,
> > > + xengnttab_grant_copy_segment_t
> > > *segs)
> > > +{
> > > +return -1;
> >
> > return -ENOSYS would be more appropriate.
> >
> >
> > Otherwise, the patch looks good.
> >
> > Thanks,
> >
> Thank you,
>
> Paulina
--
Anthony PERARD
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Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On 08/09/2016 06:56 PM, Anthony PERARD wrote:
On Tue, Aug 02, 2016 at 04:06:30PM +0200, Paulina Szubarczyk wrote:
Copy data operated on during request from/to local buffers to/from
the grant references.
Before grant copy operation local buffers must be allocated what is
done by calling ioreq_init_copy_buffers. For the 'read' operation,
first, the qemu device invokes the read operation on local buffers
and on the completion grant copy is called and buffers are freed.
For the 'write' operation grant copy is performed before invoking
write by qemu device.
A new value 'feature_grant_copy' is added to recognize when the
grant copy operation is supported by a guest.
Signed-off-by: Paulina Szubarczyk
---
Changes since v3:
- qemu_memalign/qemu_free is used instead function allocating
memory from xc.
- removed the get_buffer function instead there is a direct call
to qemu_memalign.
- moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
- added struct xengnttab_grant_copy_segment_t and stub in
xen_common.h for version of xen earlier then 480.
- added checking for version 480 to configure. The test repeats
all the operation that are required for version < 480 and
checks if xengnttab_grant_copy() is implemented.
* I did not change the way of testing if grant_copy operation is
implemented. As far as I understand if the code from
gnttab_unimp.c is used then the gnttab device is unavailable
and the handler to gntdev would be invalid. But if the handler
is valid then the ioctl should return operation unimplemented
if the gntdev does not implement the operation.
---
configure | 56 +
hw/block/xen_disk.c | 142 ++--
include/hw/xen/xen_common.h | 25
3 files changed, 218 insertions(+), 5 deletions(-)
diff --git a/configure b/configure
index f57fcc6..b5bf7d4 100755
--- a/configure
+++ b/configure
@@ -1956,6 +1956,62 @@ EOF
/*
* If we have stable libs the we don't want the libxc compat
* layers, regardless of what CFLAGS we may have been given.
+ *
+ * Also, check if xengnttab_grant_copy_segment_t is defined and
+ * grant copy operation is implemented.
+ */
+#undef XC_WANT_COMPAT_EVTCHN_API
+#undef XC_WANT_COMPAT_GNTTAB_API
+#undef XC_WANT_COMPAT_MAP_FOREIGN_API
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#if !defined(HVM_MAX_VCPUS)
+# error HVM_MAX_VCPUS not defined
+#endif
+int main(void) {
+ xc_interface *xc = NULL;
+ xenforeignmemory_handle *xfmem;
+ xenevtchn_handle *xe;
+ xengnttab_handle *xg;
+ xen_domain_handle_t handle;
+ xengnttab_grant_copy_segment_t* seg = NULL;
+
+ xs_daemon_open();
+
+ xc = xc_interface_open(0, 0, 0);
+ xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
+ xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
+ xc_hvm_inject_msi(xc, 0, 0xf000, 0x);
+ xc_hvm_create_ioreq_server(xc, 0, HVM_IOREQSRV_BUFIOREQ_ATOMIC, NULL);
+ xc_domain_create(xc, 0, handle, 0, NULL, NULL);
+
+ xfmem = xenforeignmemory_open(0, 0);
+ xenforeignmemory_map(xfmem, 0, 0, 0, 0, 0);
+
+ xe = xenevtchn_open(0, 0);
+ xenevtchn_fd(xe);
+
+ xg = xengnttab_open(0, 0);
+ xengnttab_map_grant_ref(xg, 0, 0, 0);
+ xengnttab_grant_copy(xg, 0, seg);
+
+ return 0;
+}
+EOF
+ compile_prog "" "$xen_libs $xen_stable_libs"
+then
+xen_ctrl_version=480
+xen=yes
+ elif
+ cat > $TMPC page[i] = NULL;
+}
+
+qemu_vfree(ioreq->pages);
+}
+
+static int ioreq_init_copy_buffers(struct ioreq *ioreq)
+{
+int i;
+
+if (ioreq->v.niov == 0) {
+return 0;
+}
+
+ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
+if (!ioreq->pages) {
qemu_memalign never returns NULL, you don't have to check.
+return -1;
+}
+
+for (i = 0; i < ioreq->v.niov; i++) {
+ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE;
+ioreq->v.iov[i].iov_base = ioreq->page[i];
+}
+
+return 0;
+}
+
+static int ioreq_copy(struct ioreq *ioreq)
+{
+xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
+xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+int i, count = 0, r, rc;
+int64_t file_blk = ioreq->blkdev->file_blk;
+
+if (ioreq->v.niov == 0) {
+return 0;
+}
+
+count = ioreq->v.niov;
+
+for (i = 0; i < count; i++) {
+
+if (ioreq->req.operation == BLKIF_OP_READ) {
+segs[i].flags = GNTCOPY_dest_gref;
+segs[i].dest.foreign.ref = ioreq->refs[i];
+segs[i].dest.foreign.domid = ioreq->domids[i];
+segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect *
file_blk;
+segs[i].source.virt = ioreq->v.iov[i].iov_base;
+} else {
+segs[i].flags = GNTCOPY_source_gref;
+segs[i].source.foreign.ref = ioreq->refs[i];
+segs[i].source.foreign.domid = ioreq->domids[i];
+
Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On Tue, Aug 02, 2016 at 04:06:30PM +0200, Paulina Szubarczyk wrote:
> Copy data operated on during request from/to local buffers to/from
> the grant references.
>
> Before grant copy operation local buffers must be allocated what is
> done by calling ioreq_init_copy_buffers. For the 'read' operation,
> first, the qemu device invokes the read operation on local buffers
> and on the completion grant copy is called and buffers are freed.
> For the 'write' operation grant copy is performed before invoking
> write by qemu device.
>
> A new value 'feature_grant_copy' is added to recognize when the
> grant copy operation is supported by a guest.
>
> Signed-off-by: Paulina Szubarczyk
> ---
> Changes since v3:
> - qemu_memalign/qemu_free is used instead function allocating
> memory from xc.
> - removed the get_buffer function instead there is a direct call
> to qemu_memalign.
> - moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
> - added struct xengnttab_grant_copy_segment_t and stub in
> xen_common.h for version of xen earlier then 480.
> - added checking for version 480 to configure. The test repeats
> all the operation that are required for version < 480 and
> checks if xengnttab_grant_copy() is implemented.
>
> * I did not change the way of testing if grant_copy operation is
> implemented. As far as I understand if the code from
> gnttab_unimp.c is used then the gnttab device is unavailable
> and the handler to gntdev would be invalid. But if the handler
> is valid then the ioctl should return operation unimplemented
> if the gntdev does not implement the operation.
> ---
> configure | 56 +
> hw/block/xen_disk.c | 142
> ++--
> include/hw/xen/xen_common.h | 25
> 3 files changed, 218 insertions(+), 5 deletions(-)
>
> diff --git a/configure b/configure
> index f57fcc6..b5bf7d4 100755
> --- a/configure
> +++ b/configure
> @@ -1956,6 +1956,62 @@ EOF
> /*
> * If we have stable libs the we don't want the libxc compat
> * layers, regardless of what CFLAGS we may have been given.
> + *
> + * Also, check if xengnttab_grant_copy_segment_t is defined and
> + * grant copy operation is implemented.
> + */
> +#undef XC_WANT_COMPAT_EVTCHN_API
> +#undef XC_WANT_COMPAT_GNTTAB_API
> +#undef XC_WANT_COMPAT_MAP_FOREIGN_API
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#if !defined(HVM_MAX_VCPUS)
> +# error HVM_MAX_VCPUS not defined
> +#endif
> +int main(void) {
> + xc_interface *xc = NULL;
> + xenforeignmemory_handle *xfmem;
> + xenevtchn_handle *xe;
> + xengnttab_handle *xg;
> + xen_domain_handle_t handle;
> + xengnttab_grant_copy_segment_t* seg = NULL;
> +
> + xs_daemon_open();
> +
> + xc = xc_interface_open(0, 0, 0);
> + xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
> + xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
> + xc_hvm_inject_msi(xc, 0, 0xf000, 0x);
> + xc_hvm_create_ioreq_server(xc, 0, HVM_IOREQSRV_BUFIOREQ_ATOMIC, NULL);
> + xc_domain_create(xc, 0, handle, 0, NULL, NULL);
> +
> + xfmem = xenforeignmemory_open(0, 0);
> + xenforeignmemory_map(xfmem, 0, 0, 0, 0, 0);
> +
> + xe = xenevtchn_open(0, 0);
> + xenevtchn_fd(xe);
> +
> + xg = xengnttab_open(0, 0);
> + xengnttab_map_grant_ref(xg, 0, 0, 0);
> + xengnttab_grant_copy(xg, 0, seg);
> +
> + return 0;
> +}
> +EOF
> + compile_prog "" "$xen_libs $xen_stable_libs"
> +then
> +xen_ctrl_version=480
> +xen=yes
> + elif
> + cat > $TMPC < +/*
> + * If we have stable libs the we don't want the libxc compat
> + * layers, regardless of what CFLAGS we may have been given.
> */
> #undef XC_WANT_COMPAT_EVTCHN_API
> #undef XC_WANT_COMPAT_GNTTAB_API
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index 3b8ad33..2dd1464 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -119,6 +119,9 @@ struct XenBlkDev {
> unsigned intpersistent_gnt_count;
> unsigned intmax_grants;
>
> +/* Grant copy */
> +gbooleanfeature_grant_copy;
> +
> /* qemu block driver */
> DriveInfo *dinfo;
> BlockBackend*blk;
> @@ -489,6 +492,95 @@ static int ioreq_map(struct ioreq *ioreq)
> return 0;
> }
>
> +static void free_buffers(struct ioreq *ioreq)
> +{
> +int i;
> +
> +for (i = 0; i < ioreq->v.niov; i++) {
> +ioreq->page[i] = NULL;
> +}
> +
> +qemu_vfree(ioreq->pages);
> +}
> +
> +static int ioreq_init_copy_buffers(struct ioreq *ioreq)
> +{
> +int i;
> +
> +if (ioreq->v.niov == 0) {
> +return 0;
> +}
> +
> +ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
> +if (!ioreq->pages) {
qemu_memalign never returns NULL, you don't have to check.
> +return -1;
> +}
> +
> +for (i = 0; i < ioreq->v.niov; i++) {
> +ioreq->page[i] = ioreq->pages + i * XC_PAGE_SI
Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On 08/02/2016 04:06 PM, Paulina Szubarczyk wrote:
Copy data operated on during request from/to local buffers to/from
the grant references.
Before grant copy operation local buffers must be allocated what is
done by calling ioreq_init_copy_buffers. For the 'read' operation,
first, the qemu device invokes the read operation on local buffers
and on the completion grant copy is called and buffers are freed.
For the 'write' operation grant copy is performed before invoking
write by qemu device.
A new value 'feature_grant_copy' is added to recognize when the
grant copy operation is supported by a guest.
Signed-off-by: Paulina Szubarczyk
---
Changes since v3:
- qemu_memalign/qemu_free is used instead function allocating
memory from xc.
- removed the get_buffer function instead there is a direct call
to qemu_memalign.
- moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
- added struct xengnttab_grant_copy_segment_t and stub in
xen_common.h for version of xen earlier then 480.
- added checking for version 480 to configure. The test repeats
all the operation that are required for version < 480 and
checks if xengnttab_grant_copy() is implemented.
* I did not change the way of testing if grant_copy operation is
implemented. As far as I understand if the code from
gnttab_unimp.c is used then the gnttab device is unavailable
and the handler to gntdev would be invalid. But if the handler
is valid then the ioctl should return operation unimplemented
if the gntdev does not implement the operation.
---
configure | 56 +
hw/block/xen_disk.c | 142 ++--
include/hw/xen/xen_common.h | 25
3 files changed, 218 insertions(+), 5 deletions(-)
/* qemu block driver */
DriveInfo *dinfo;
BlockBackend*blk;
@@ -489,6 +492,95 @@ static int ioreq_map(struct ioreq *ioreq)
return 0;
}
static void qemu_aio_complete(void *opaque, int ret)
@@ -511,8 +603,29 @@ static void qemu_aio_complete(void *opaque, int ret)
return;
}
+if (ioreq->blkdev->feature_grant_copy) {
+switch (ioreq->req.operation) {
+case BLKIF_OP_READ:
+/* in case of failure ioreq->aio_errors is increased */
+ioreq_copy(ioreq);
I would add a condition to invoke the grant copy only if the ret
argument with which the callback from BlockBackend
'qemu_aio_complete(void *opaque, int ret)' is called is equal to 0
to not unnecessary copy invalid data.
+free_buffers(ioreq);
+break;
+case BLKIF_OP_WRITE:
+case BLKIF_OP_FLUSH_DISKCACHE:
+if (!ioreq->req.nr_segments) {
+break;
+}
+free_buffers(ioreq);
+break;
+default:
+break;
+}
+}
+
ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
-ioreq_unmap(ioreq);
+if (!ioreq->blkdev->feature_grant_copy) {
+ioreq_unmap(ioreq);
+}
ioreq_finish(ioreq);
switch (ioreq->req.operation) {
case BLKIF_OP_WRITE:
Paulina
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Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On 08/08/2016 01:11 PM, Roger Pau Monné wrote:
On Tue, Aug 02, 2016 at 04:06:30PM +0200, Paulina Szubarczyk wrote:
Copy data operated on during request from/to local buffers to/from
the grant references.
Before grant copy operation local buffers must be allocated what is
done by calling ioreq_init_copy_buffers. For the 'read' operation,
first, the qemu device invokes the read operation on local buffers
and on the completion grant copy is called and buffers are freed.
For the 'write' operation grant copy is performed before invoking
write by qemu device.
A new value 'feature_grant_copy' is added to recognize when the
grant copy operation is supported by a guest.
Signed-off-by: Paulina Szubarczyk
Thanks, this is looking good, just a couple of minor comments below.
Thank you for the review, I will apply the comments.
---
Changes since v3:
- qemu_memalign/qemu_free is used instead function allocating
memory from xc.
- removed the get_buffer function instead there is a direct call
to qemu_memalign.
- moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
- added struct xengnttab_grant_copy_segment_t and stub in
xen_common.h for version of xen earlier then 480.
- added checking for version 480 to configure. The test repeats
all the operation that are required for version < 480 and
checks if xengnttab_grant_copy() is implemented.
* I did not change the way of testing if grant_copy operation is
implemented. As far as I understand if the code from
gnttab_unimp.c is used then the gnttab device is unavailable
and the handler to gntdev would be invalid. But if the handler
is valid then the ioctl should return operation unimplemented
if the gntdev does not implement the operation.
---
configure | 56 +
hw/block/xen_disk.c | 142 ++--
include/hw/xen/xen_common.h | 25
3 files changed, 218 insertions(+), 5 deletions(-)
diff --git a/configure b/configure
index f57fcc6..b5bf7d4 100755
--- a/configure
+++ b/configure
@@ -1956,6 +1956,62 @@ EOF
/*
* If we have stable libs the we don't want the libxc compat
* layers, regardless of what CFLAGS we may have been given.
+ *
+ * Also, check if xengnttab_grant_copy_segment_t is defined and
+ * grant copy operation is implemented.
+ */
+#undef XC_WANT_COMPAT_EVTCHN_API
+#undef XC_WANT_COMPAT_GNTTAB_API
+#undef XC_WANT_COMPAT_MAP_FOREIGN_API
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#if !defined(HVM_MAX_VCPUS)
+# error HVM_MAX_VCPUS not defined
+#endif
+int main(void) {
+ xc_interface *xc = NULL;
+ xenforeignmemory_handle *xfmem;
+ xenevtchn_handle *xe;
+ xengnttab_handle *xg;
+ xen_domain_handle_t handle;
+ xengnttab_grant_copy_segment_t* seg = NULL;
+
+ xs_daemon_open();
+
+ xc = xc_interface_open(0, 0, 0);
+ xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
+ xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
+ xc_hvm_inject_msi(xc, 0, 0xf000, 0x);
+ xc_hvm_create_ioreq_server(xc, 0, HVM_IOREQSRV_BUFIOREQ_ATOMIC, NULL);
+ xc_domain_create(xc, 0, handle, 0, NULL, NULL);
+
+ xfmem = xenforeignmemory_open(0, 0);
+ xenforeignmemory_map(xfmem, 0, 0, 0, 0, 0);
+
+ xe = xenevtchn_open(0, 0);
+ xenevtchn_fd(xe);
+
+ xg = xengnttab_open(0, 0);
+ xengnttab_map_grant_ref(xg, 0, 0, 0);
I don't think you need to check xengnttab_map_grant_ref, just
xengnttab_grant_copy should be enough? Since xengnttab_grant_copy was added
later you can assume xengnttab_map_grant_ref will be there.
+ xengnttab_grant_copy(xg, 0, seg);
+
+ return 0;
+}
+EOF
+ compile_prog "" "$xen_libs $xen_stable_libs"
+then
+xen_ctrl_version=480
+xen=yes
+ elif
+ cat > $TMPC page[i] = NULL;
+}
+
+qemu_vfree(ioreq->pages);
+}
+
+static int ioreq_init_copy_buffers(struct ioreq *ioreq)
+{
+int i;
+
+if (ioreq->v.niov == 0) {
+return 0;
+}
+
+ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
+if (!ioreq->pages) {
+return -1;
+}
+
+for (i = 0; i < ioreq->v.niov; i++) {
+ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE;
+ioreq->v.iov[i].iov_base = ioreq->page[i];
+}
+
+return 0;
+}
+
+static int ioreq_copy(struct ioreq *ioreq)
+{
+xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
+xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+int i, count = 0, r, rc;
Why do you need to initialize count to 0 here? A couple of lines below you
inconditionally set it to ioreq->v.niov.
+int64_t file_blk = ioreq->blkdev->file_blk;
+
+if (ioreq->v.niov == 0) {
+return 0;
+}
+
+count = ioreq->v.niov;
+
+for (i = 0; i < count; i++) {
+
+if (ioreq->req.operation == BLKIF_OP_READ) {
+segs[i].flags = GNTCOPY_dest_gref;
+segs[i].dest.foreign.ref = ioreq->refs[i];
+
Re: [Xen-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation
On Tue, Aug 02, 2016 at 04:06:30PM +0200, Paulina Szubarczyk wrote:
> Copy data operated on during request from/to local buffers to/from
> the grant references.
>
> Before grant copy operation local buffers must be allocated what is
> done by calling ioreq_init_copy_buffers. For the 'read' operation,
> first, the qemu device invokes the read operation on local buffers
> and on the completion grant copy is called and buffers are freed.
> For the 'write' operation grant copy is performed before invoking
> write by qemu device.
>
> A new value 'feature_grant_copy' is added to recognize when the
> grant copy operation is supported by a guest.
>
> Signed-off-by: Paulina Szubarczyk
Thanks, this is looking good, just a couple of minor comments below.
> ---
> Changes since v3:
> - qemu_memalign/qemu_free is used instead function allocating
> memory from xc.
> - removed the get_buffer function instead there is a direct call
> to qemu_memalign.
> - moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
> - added struct xengnttab_grant_copy_segment_t and stub in
> xen_common.h for version of xen earlier then 480.
> - added checking for version 480 to configure. The test repeats
> all the operation that are required for version < 480 and
> checks if xengnttab_grant_copy() is implemented.
>
> * I did not change the way of testing if grant_copy operation is
> implemented. As far as I understand if the code from
> gnttab_unimp.c is used then the gnttab device is unavailable
> and the handler to gntdev would be invalid. But if the handler
> is valid then the ioctl should return operation unimplemented
> if the gntdev does not implement the operation.
> ---
> configure | 56 +
> hw/block/xen_disk.c | 142
> ++--
> include/hw/xen/xen_common.h | 25
> 3 files changed, 218 insertions(+), 5 deletions(-)
>
> diff --git a/configure b/configure
> index f57fcc6..b5bf7d4 100755
> --- a/configure
> +++ b/configure
> @@ -1956,6 +1956,62 @@ EOF
> /*
> * If we have stable libs the we don't want the libxc compat
> * layers, regardless of what CFLAGS we may have been given.
> + *
> + * Also, check if xengnttab_grant_copy_segment_t is defined and
> + * grant copy operation is implemented.
> + */
> +#undef XC_WANT_COMPAT_EVTCHN_API
> +#undef XC_WANT_COMPAT_GNTTAB_API
> +#undef XC_WANT_COMPAT_MAP_FOREIGN_API
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#if !defined(HVM_MAX_VCPUS)
> +# error HVM_MAX_VCPUS not defined
> +#endif
> +int main(void) {
> + xc_interface *xc = NULL;
> + xenforeignmemory_handle *xfmem;
> + xenevtchn_handle *xe;
> + xengnttab_handle *xg;
> + xen_domain_handle_t handle;
> + xengnttab_grant_copy_segment_t* seg = NULL;
> +
> + xs_daemon_open();
> +
> + xc = xc_interface_open(0, 0, 0);
> + xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
> + xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
> + xc_hvm_inject_msi(xc, 0, 0xf000, 0x);
> + xc_hvm_create_ioreq_server(xc, 0, HVM_IOREQSRV_BUFIOREQ_ATOMIC, NULL);
> + xc_domain_create(xc, 0, handle, 0, NULL, NULL);
> +
> + xfmem = xenforeignmemory_open(0, 0);
> + xenforeignmemory_map(xfmem, 0, 0, 0, 0, 0);
> +
> + xe = xenevtchn_open(0, 0);
> + xenevtchn_fd(xe);
> +
> + xg = xengnttab_open(0, 0);
> + xengnttab_map_grant_ref(xg, 0, 0, 0);
I don't think you need to check xengnttab_map_grant_ref, just
xengnttab_grant_copy should be enough? Since xengnttab_grant_copy was added
later you can assume xengnttab_map_grant_ref will be there.
> + xengnttab_grant_copy(xg, 0, seg);
> +
> + return 0;
> +}
> +EOF
> + compile_prog "" "$xen_libs $xen_stable_libs"
> +then
> +xen_ctrl_version=480
> +xen=yes
> + elif
> + cat > $TMPC < +/*
> + * If we have stable libs the we don't want the libxc compat
> + * layers, regardless of what CFLAGS we may have been given.
> */
> #undef XC_WANT_COMPAT_EVTCHN_API
> #undef XC_WANT_COMPAT_GNTTAB_API
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index 3b8ad33..2dd1464 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -119,6 +119,9 @@ struct XenBlkDev {
> unsigned intpersistent_gnt_count;
> unsigned intmax_grants;
>
> +/* Grant copy */
> +gbooleanfeature_grant_copy;
> +
> /* qemu block driver */
> DriveInfo *dinfo;
> BlockBackend*blk;
> @@ -489,6 +492,95 @@ static int ioreq_map(struct ioreq *ioreq)
> return 0;
> }
>
> +static void free_buffers(struct ioreq *ioreq)
> +{
> +int i;
> +
> +for (i = 0; i < ioreq->v.niov; i++) {
> +ioreq->page[i] = NULL;
> +}
> +
> +qemu_vfree(ioreq->pages);
> +}
> +
> +static int ioreq_init_copy_buffers(struct ioreq *ioreq)
> +{
> +int i;
> +
> +if (ioreq->v.niov == 0) {
> +return 0;
> +}
> +
> +ioreq->pages = qemu_memalig
