| Message ID | 1525461967-32174-2-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, May 04, 2018 at 08:26:00PM +0100, Paul Durrant wrote: > This patch adds grant table helper functions to the xen_backend code to > localize error reporting and use of xen_domid. > > The patch also defers the call to xengnttab_open() until just before the > initialise method in XenDevOps is invoked. This method is responsible for > mapping the shared ring. No prior method requires access to the grant table. > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > --- > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > > v2: > - New in v2 > --- > hw/xen/xen_backend.c | 123 ++++++++++++++++++++++++++++++++++++++----- > include/hw/xen/xen_backend.h | 33 ++++++++++++ > 2 files changed, 144 insertions(+), 12 deletions(-) > > diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c > index 7445b50..50412d6 100644 > --- a/hw/xen/xen_backend.c > +++ b/hw/xen/xen_backend.c > @@ -106,6 +106,103 @@ int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state) > return 0; > } > > +void xen_be_set_max_grant_refs(struct XenDevice *xendev, > + unsigned int nr_refs) Is it fine to ignore error from set_max_grants and continue ? xen_disk.c seems to fail the initialisation if set_max_grants call fails. On the other end, xen-usb.c just keep going. > +{ > + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); > + > + if (xengnttab_set_max_grants(xendev->gnttabdev, nr_refs)) { > + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > + strerror(errno)); > + } > +} > + > +int xen_be_copy_grant_refs(struct XenDevice *xendev, > + bool to_domain, > + XenGrantCopySegment segs[], > + unsigned int nr_segs) > +{ > + xengnttab_grant_copy_segment_t *xengnttab_segs; > + unsigned int i; > + int rc; > + > + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); > + > + xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs); > + > + for (i = 0; i < nr_segs; i++) { > + XenGrantCopySegment *seg = &segs[i]; > + xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i]; > + > + if (to_domain) { > + xengnttab_seg->flags = GNTCOPY_dest_gref; > + xengnttab_seg->dest.foreign.domid = xen_domid; > + xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref; > + xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset; > + xengnttab_seg->source.virt = seg->source.virt; > + } else { > + xengnttab_seg->flags = GNTCOPY_source_gref; > + xengnttab_seg->source.foreign.domid = xen_domid; > + xengnttab_seg->source.foreign.ref = seg->source.foreign.ref; > + xengnttab_seg->source.foreign.offset = > + seg->source.foreign.offset; > + xengnttab_seg->dest.virt = seg->dest.virt; > + } That's not going to work because xengnttab_grant_copy_segment_t doesn't exist on Xen 4.7. > + > + xengnttab_seg->len = seg->len; > + } > + > + rc = xengnttab_grant_copy(xendev->gnttabdev, nr_segs, xengnttab_segs); Thanks,
> -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 16 May 2018 14:50 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: xen-devel@lists.xenproject.org; qemu-block@nongnu.org; qemu- > devel@nongnu.org; Stefano Stabellini <sstabellini@kernel.org> > Subject: Re: [PATCH v3 1/8] xen_backend: add grant table helpers > > On Fri, May 04, 2018 at 08:26:00PM +0100, Paul Durrant wrote: > > This patch adds grant table helper functions to the xen_backend code to > > localize error reporting and use of xen_domid. > > > > The patch also defers the call to xengnttab_open() until just before the > > initialise method in XenDevOps is invoked. This method is responsible for > > mapping the shared ring. No prior method requires access to the grant > table. > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > --- > > Cc: Stefano Stabellini <sstabellini@kernel.org> > > Cc: Anthony Perard <anthony.perard@citrix.com> > > > > v2: > > - New in v2 > > --- > > hw/xen/xen_backend.c | 123 > ++++++++++++++++++++++++++++++++++++++----- > > include/hw/xen/xen_backend.h | 33 ++++++++++++ > > 2 files changed, 144 insertions(+), 12 deletions(-) > > > > diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c > > index 7445b50..50412d6 100644 > > --- a/hw/xen/xen_backend.c > > +++ b/hw/xen/xen_backend.c > > @@ -106,6 +106,103 @@ int xen_be_set_state(struct XenDevice *xendev, > enum xenbus_state state) > > return 0; > > } > > > > +void xen_be_set_max_grant_refs(struct XenDevice *xendev, > > + unsigned int nr_refs) > > Is it fine to ignore error from set_max_grants and continue ? xen_disk.c > seems to fail the initialisation if set_max_grants call fails. On the > other end, xen-usb.c just keep going. > I guess the upshot will be that a subsequent grant map would fail, so I think it should be sufficient to deal with the failure there. As you say it's use is inconsistent, and just plain missing in some cases. > > +{ > > + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); > > + > > + if (xengnttab_set_max_grants(xendev->gnttabdev, nr_refs)) { > > + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > > + strerror(errno)); > > + } > > +} > > + > > > +int xen_be_copy_grant_refs(struct XenDevice *xendev, > > + bool to_domain, > > + XenGrantCopySegment segs[], > > + unsigned int nr_segs) > > +{ > > + xengnttab_grant_copy_segment_t *xengnttab_segs; > > + unsigned int i; > > + int rc; > > + > > + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); > > + > > + xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, > nr_segs); > > + > > + for (i = 0; i < nr_segs; i++) { > > + XenGrantCopySegment *seg = &segs[i]; > > + xengnttab_grant_copy_segment_t *xengnttab_seg = > &xengnttab_segs[i]; > > + > > + if (to_domain) { > > + xengnttab_seg->flags = GNTCOPY_dest_gref; > > + xengnttab_seg->dest.foreign.domid = xen_domid; > > + xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref; > > + xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset; > > + xengnttab_seg->source.virt = seg->source.virt; > > + } else { > > + xengnttab_seg->flags = GNTCOPY_source_gref; > > + xengnttab_seg->source.foreign.domid = xen_domid; > > + xengnttab_seg->source.foreign.ref = seg->source.foreign.ref; > > + xengnttab_seg->source.foreign.offset = > > + seg->source.foreign.offset; > > + xengnttab_seg->dest.virt = seg->dest.virt; > > + } > > That's not going to work because xengnttab_grant_copy_segment_t doesn't > exist on Xen 4.7. Ah, I'd missed the ifdef around that in xen_disk. I'll add it here. Cheers, Paul > > > + > > + xengnttab_seg->len = seg->len; > > + } > > + > > + rc = xengnttab_grant_copy(xendev->gnttabdev, nr_segs, > xengnttab_segs); > > Thanks, > > -- > Anthony PERARD
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c index 7445b50..50412d6 100644 --- a/hw/xen/xen_backend.c +++ b/hw/xen/xen_backend.c @@ -106,6 +106,103 @@ int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state) return 0; } +void xen_be_set_max_grant_refs(struct XenDevice *xendev, + unsigned int nr_refs) +{ + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); + + if (xengnttab_set_max_grants(xendev->gnttabdev, nr_refs)) { + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", + strerror(errno)); + } +} + +void *xen_be_map_grant_refs(struct XenDevice *xendev, uint32_t *refs, + unsigned int nr_refs, int prot) +{ + void *ptr; + + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); + + ptr = xengnttab_map_domain_grant_refs(xendev->gnttabdev, nr_refs, + xen_domid, refs, prot); + if (!ptr) { + xen_pv_printf(xendev, 0, + "xengnttab_map_domain_grant_refs failed: %s\n", + strerror(errno)); + } + + return ptr; +} + +void xen_be_unmap_grant_refs(struct XenDevice *xendev, void *ptr, + unsigned int nr_refs) +{ + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); + + if (xengnttab_unmap(xendev->gnttabdev, ptr, nr_refs)) { + xen_pv_printf(xendev, 0, "xengnttab_unmap failed: %s\n", + strerror(errno)); + } +} + +int xen_be_copy_grant_refs(struct XenDevice *xendev, + bool to_domain, + XenGrantCopySegment segs[], + unsigned int nr_segs) +{ + xengnttab_grant_copy_segment_t *xengnttab_segs; + unsigned int i; + int rc; + + assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); + + xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs); + + for (i = 0; i < nr_segs; i++) { + XenGrantCopySegment *seg = &segs[i]; + xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i]; + + if (to_domain) { + xengnttab_seg->flags = GNTCOPY_dest_gref; + xengnttab_seg->dest.foreign.domid = xen_domid; + xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref; + xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset; + xengnttab_seg->source.virt = seg->source.virt; + } else { + xengnttab_seg->flags = GNTCOPY_source_gref; + xengnttab_seg->source.foreign.domid = xen_domid; + xengnttab_seg->source.foreign.ref = seg->source.foreign.ref; + xengnttab_seg->source.foreign.offset = + seg->source.foreign.offset; + xengnttab_seg->dest.virt = seg->dest.virt; + } + + xengnttab_seg->len = seg->len; + } + + rc = xengnttab_grant_copy(xendev->gnttabdev, nr_segs, xengnttab_segs); + + if (rc) { + xen_pv_printf(xendev, 0, "xengnttab_copy failed: %s\n", + strerror(errno)); + } + + for (i = 0; i < nr_segs; i++) { + xengnttab_grant_copy_segment_t *xengnttab_seg = + &xengnttab_segs[i]; + + if (xengnttab_seg->status != GNTST_okay) { + xen_pv_printf(xendev, 0, "segment[%u] status: %d\n", i, + xengnttab_seg->status); + rc = -1; + } + } + + g_free(xengnttab_segs); + return rc; +} + /* * get xen backend device, allocate a new one if it doesn't exist. */ @@ -149,18 +246,6 @@ static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev, } qemu_set_cloexec(xenevtchn_fd(xendev->evtchndev)); - if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) { - xendev->gnttabdev = xengnttab_open(NULL, 0); - if (xendev->gnttabdev == NULL) { - xen_pv_printf(NULL, 0, "can't open gnttab device\n"); - xenevtchn_close(xendev->evtchndev); - qdev_unplug(DEVICE(xendev), NULL); - return NULL; - } - } else { - xendev->gnttabdev = NULL; - } - xen_pv_insert_xendev(xendev); if (xendev->ops->alloc) { @@ -322,6 +407,16 @@ static int xen_be_try_initialise(struct XenDevice *xendev) } } + if (xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV) { + xendev->gnttabdev = xengnttab_open(NULL, 0); + if (xendev->gnttabdev == NULL) { + xen_pv_printf(NULL, 0, "can't open gnttab device\n"); + return -1; + } + } else { + xendev->gnttabdev = NULL; + } + if (xendev->ops->initialise) { rc = xendev->ops->initialise(xendev); } @@ -369,6 +464,10 @@ static void xen_be_disconnect(struct XenDevice *xendev, enum xenbus_state state) xendev->ops->disconnect) { xendev->ops->disconnect(xendev); } + if (xendev->gnttabdev) { + xengnttab_close(xendev->gnttabdev); + xendev->gnttabdev = NULL; + } if (xendev->be_state != state) { xen_be_set_state(xendev, state); } diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h index 3a27692..29bf1c3 100644 --- a/include/hw/xen/xen_backend.h +++ b/include/hw/xen/xen_backend.h @@ -42,6 +42,39 @@ void xen_be_register_common(void); int xen_be_register(const char *type, struct XenDevOps *ops); int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state); int xen_be_bind_evtchn(struct XenDevice *xendev); +void xen_be_set_max_grant_refs(struct XenDevice *xendev, + unsigned int nr_refs); +void *xen_be_map_grant_refs(struct XenDevice *xendev, uint32_t *refs, + unsigned int nr_refs, int prot); +void xen_be_unmap_grant_refs(struct XenDevice *xendev, void *ptr, + unsigned int nr_refs); + +typedef struct XenGrantCopySegment { + union { + void *virt; + struct { + uint32_t ref; + off_t offset; + } foreign; + } source, dest; + size_t len; +} XenGrantCopySegment; + +int xen_be_copy_grant_refs(struct XenDevice *xendev, + bool to_domain, XenGrantCopySegment segs[], + unsigned int nr_segs); + +static inline void *xen_be_map_grant_ref(struct XenDevice *xendev, + uint32_t ref, int prot) +{ + return xen_be_map_grant_refs(xendev, &ref, 1, prot); +} + +static inline void xen_be_unmap_grant_ref(struct XenDevice *xendev, + void *ptr) +{ + return xen_be_unmap_grant_refs(xendev, ptr, 1); +} /* actual backend drivers */ extern struct XenDevOps xen_console_ops; /* xen_console.c */
This patch adds grant table helper functions to the xen_backend code to localize error reporting and use of xen_domid. The patch also defers the call to xengnttab_open() until just before the initialise method in XenDevOps is invoked. This method is responsible for mapping the shared ring. No prior method requires access to the grant table. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> v2: - New in v2 --- hw/xen/xen_backend.c | 123 ++++++++++++++++++++++++++++++++++++++----- include/hw/xen/xen_backend.h | 33 ++++++++++++ 2 files changed, 144 insertions(+), 12 deletions(-)