| Message ID | 20170620134756.9632-3-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 20 Jun 2017, Paul Durrant wrote: > The blkif protocol has had provision for negotiation of multi-page shared > rings for some time now and many guest OS have support in their frontend > drivers. > > This patch makes the necessary modifications to xen-disk support a shared > ring up to order 4 (i.e. 16 pages). > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Thanks for the patch! > --- > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > Cc: Kevin Wolf <kwolf@redhat.com> > Cc: Max Reitz <mreitz@redhat.com> > --- > hw/block/xen_disk.c | 141 ++++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 110 insertions(+), 31 deletions(-) > > diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c > index 9b06e3aa81..a9942d32db 100644 > --- a/hw/block/xen_disk.c > +++ b/hw/block/xen_disk.c > @@ -36,8 +36,6 @@ > > static int batch_maps = 0; > > -static int max_requests = 32; > - > /* ------------------------------------------------------------- */ > > #define BLOCK_SIZE 512 > @@ -84,6 +82,8 @@ struct ioreq { > BlockAcctCookie acct; > }; > > +#define MAX_RING_PAGE_ORDER 4 > + > struct XenBlkDev { > struct XenDevice xendev; /* must be first */ > char *params; > @@ -94,7 +94,8 @@ struct XenBlkDev { > bool directiosafe; > const char *fileproto; > const char *filename; > - int ring_ref; > + unsigned int ring_ref[1 << MAX_RING_PAGE_ORDER]; > + unsigned int nr_ring_ref; > void *sring; > int64_t file_blk; > int64_t file_size; > @@ -110,6 +111,7 @@ struct XenBlkDev { > int requests_total; > int requests_inflight; > int requests_finished; > + unsigned int max_requests; > > /* Persistent grants extension */ > gboolean feature_discard; > @@ -199,7 +201,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) > struct ioreq *ioreq = NULL; > > if (QLIST_EMPTY(&blkdev->freelist)) { > - if (blkdev->requests_total >= max_requests) { > + if (blkdev->requests_total >= blkdev->max_requests) { > goto out; > } > /* allocate new struct */ > @@ -905,7 +907,7 @@ static void blk_handle_requests(struct XenBlkDev *blkdev) > ioreq_runio_qemu_aio(ioreq); > } > > - if (blkdev->more_work && blkdev->requests_inflight < max_requests) { > + if (blkdev->more_work && blkdev->requests_inflight < blkdev->max_requests) { > qemu_bh_schedule(blkdev->bh); > } > } > @@ -918,15 +920,6 @@ static void blk_bh(void *opaque) > blk_handle_requests(blkdev); > } > > -/* > - * We need to account for the grant allocations requiring contiguous > - * chunks; the worst case number would be > - * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, > - * but in order to keep things simple just use > - * 2 * max_req * max_seg. > - */ > -#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) > - > static void blk_alloc(struct XenDevice *xendev) > { > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); > @@ -938,11 +931,6 @@ static void blk_alloc(struct XenDevice *xendev) > if (xen_mode != XEN_EMULATE) { > batch_maps = 1; > } > - if (xengnttab_set_max_grants(xendev->gnttabdev, > - MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { > - xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > - strerror(errno)); > - } > } > > static void blk_parse_discard(struct XenBlkDev *blkdev) > @@ -1037,6 +1025,9 @@ static int blk_init(struct XenDevice *xendev) > !blkdev->feature_grant_copy); > xenstore_write_be_int(&blkdev->xendev, "info", info); > > + xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order", > + MAX_RING_PAGE_ORDER); > + > blk_parse_discard(blkdev); > > g_free(directiosafe); > @@ -1058,12 +1049,25 @@ out_error: > return -1; > } > > +/* > + * We need to account for the grant allocations requiring contiguous > + * chunks; the worst case number would be > + * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, > + * but in order to keep things simple just use > + * 2 * max_req * max_seg. > + */ > +#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) > + > static int blk_connect(struct XenDevice *xendev) > { > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); > int pers, index, qflags; > bool readonly = true; > bool writethrough = true; > + int order, ring_ref; > + unsigned int ring_size, max_grants; > + unsigned int i; > + uint32_t *domids; > > /* read-only ? */ > if (blkdev->directiosafe) { > @@ -1138,9 +1142,39 @@ static int blk_connect(struct XenDevice *xendev) > xenstore_write_be_int64(&blkdev->xendev, "sectors", > blkdev->file_size / blkdev->file_blk); > > - if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) { > + if (xenstore_read_fe_int(&blkdev->xendev, "ring-page-order", > + &order) == -1) { > + blkdev->nr_ring_ref = 1; > + > + if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", > + &ring_ref) == -1) { > + return -1; > + } > + blkdev->ring_ref[0] = ring_ref; > + > + } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) { > + blkdev->nr_ring_ref = 1 << order; > + > + for (i = 0; i < blkdev->nr_ring_ref; i++) { > + char *key; > + > + key = g_strdup_printf("ring-ref%u", i); > + if (!key) { > + return -1; > + } > + > + if (xenstore_read_fe_int(&blkdev->xendev, key, > + &ring_ref) == -1) { it looks like we are leaking key. > + return -1; > + } > + blkdev->ring_ref[i] = ring_ref; > + > + g_free(key); > + } > + } else { > return -1; I would like to print warning if the requested ring size exceeds our limit. > } > + > if (xenstore_read_fe_int(&blkdev->xendev, "event-channel", > &blkdev->xendev.remote_port) == -1) { > return -1; > @@ -1163,41 +1197,85 @@ static int blk_connect(struct XenDevice *xendev) > blkdev->protocol = BLKIF_PROTOCOL_NATIVE; > } > > - blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev, > - blkdev->xendev.dom, > - blkdev->ring_ref, > - PROT_READ | PROT_WRITE); > + ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref; > + switch (blkdev->protocol) { > + case BLKIF_PROTOCOL_NATIVE: > + { > + blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size); > + break; > + } > + case BLKIF_PROTOCOL_X86_32: > + { > + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, ring_size); > + break; > + } > + case BLKIF_PROTOCOL_X86_64: > + { > + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, ring_size); > + break; > + } > + default: > + return -1; > + } > + > + /* Calculate the maximum number of grants needed by ioreqs */ > + max_grants = MAX_GRANTS(blkdev->max_requests, > + BLKIF_MAX_SEGMENTS_PER_REQUEST); > + /* Add on the number needed for the ring pages */ > + max_grants += blkdev->nr_ring_ref; > + > + if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, max_grants)) { > + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > + strerror(errno)); > + return -1; > + } > + > + domids = g_malloc0_n(blkdev->nr_ring_ref, sizeof(uint32_t)); > + for (i = 0; i < blkdev->nr_ring_ref; i++) { > + domids[i] = blkdev->xendev.dom; > + } > + > + blkdev->sring = xengnttab_map_grant_refs(blkdev->xendev.gnttabdev, > + blkdev->nr_ring_ref, > + domids, > + blkdev->ring_ref, > + PROT_READ | PROT_WRITE); > + > + g_free(domids); > + > if (!blkdev->sring) { > return -1; > } > + > blkdev->cnt_map++; > > switch (blkdev->protocol) { > case BLKIF_PROTOCOL_NATIVE: > { > blkif_sring_t *sring_native = blkdev->sring; > - BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE); > + BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size); > break; > } > case BLKIF_PROTOCOL_X86_32: > { > blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring; > > - BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE); > + BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, ring_size); > break; > } > case BLKIF_PROTOCOL_X86_64: > { > blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring; > > - BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE); > + BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, ring_size); > break; > } > } > > if (blkdev->feature_persistent) { > /* Init persistent grants */ > - blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST; > + blkdev->max_grants = blkdev->max_requests * > + BLKIF_MAX_SEGMENTS_PER_REQUEST; > blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp, > NULL, NULL, > batch_maps ? > @@ -1209,9 +1287,9 @@ static int blk_connect(struct XenDevice *xendev) > > xen_be_bind_evtchn(&blkdev->xendev); > > - xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " > + xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, nr-ring-ref %u, " > "remote port %d, local port %d\n", > - blkdev->xendev.protocol, blkdev->ring_ref, > + blkdev->xendev.protocol, blkdev->nr_ring_ref, > blkdev->xendev.remote_port, blkdev->xendev.local_port); > return 0; > } > @@ -1228,7 +1306,8 @@ static void blk_disconnect(struct XenDevice *xendev) > xen_pv_unbind_evtchn(&blkdev->xendev); > > if (blkdev->sring) { > - xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); > + xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, > + blkdev->nr_ring_ref); > blkdev->cnt_map--; > blkdev->sring = NULL; > } > -- > 2.11.0 >
> -----Original Message----- > From: Stefano Stabellini [mailto:sstabellini@kernel.org] > Sent: 20 June 2017 23:51 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: xen-devel@lists.xenproject.org; qemu-devel@nongnu.org; qemu- > block@nongnu.org; Stefano Stabellini <sstabellini@kernel.org>; Anthony > Perard <anthony.perard@citrix.com>; Kevin Wolf <kwolf@redhat.com>; > Max Reitz <mreitz@redhat.com> > Subject: Re: [PATCH 2/3] xen-disk: add support for multi-page shared rings > > On Tue, 20 Jun 2017, Paul Durrant wrote: > > The blkif protocol has had provision for negotiation of multi-page shared > > rings for some time now and many guest OS have support in their frontend > > drivers. > > > > This patch makes the necessary modifications to xen-disk support a shared > > ring up to order 4 (i.e. 16 pages). > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > Thanks for the patch! > You're welcome. > > --- > > Cc: Stefano Stabellini <sstabellini@kernel.org> > > Cc: Anthony Perard <anthony.perard@citrix.com> > > Cc: Kevin Wolf <kwolf@redhat.com> > > Cc: Max Reitz <mreitz@redhat.com> > > --- > > hw/block/xen_disk.c | 141 > ++++++++++++++++++++++++++++++++++++++++------------ > > 1 file changed, 110 insertions(+), 31 deletions(-) > > > > diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c > > index 9b06e3aa81..a9942d32db 100644 > > --- a/hw/block/xen_disk.c > > +++ b/hw/block/xen_disk.c > > @@ -36,8 +36,6 @@ > > > > static int batch_maps = 0; > > > > -static int max_requests = 32; > > - > > /* ------------------------------------------------------------- */ > > > > #define BLOCK_SIZE 512 > > @@ -84,6 +82,8 @@ struct ioreq { > > BlockAcctCookie acct; > > }; > > > > +#define MAX_RING_PAGE_ORDER 4 > > + > > struct XenBlkDev { > > struct XenDevice xendev; /* must be first */ > > char *params; > > @@ -94,7 +94,8 @@ struct XenBlkDev { > > bool directiosafe; > > const char *fileproto; > > const char *filename; > > - int ring_ref; > > + unsigned int ring_ref[1 << MAX_RING_PAGE_ORDER]; > > + unsigned int nr_ring_ref; > > void *sring; > > int64_t file_blk; > > int64_t file_size; > > @@ -110,6 +111,7 @@ struct XenBlkDev { > > int requests_total; > > int requests_inflight; > > int requests_finished; > > + unsigned int max_requests; > > > > /* Persistent grants extension */ > > gboolean feature_discard; > > @@ -199,7 +201,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev > *blkdev) > > struct ioreq *ioreq = NULL; > > > > if (QLIST_EMPTY(&blkdev->freelist)) { > > - if (blkdev->requests_total >= max_requests) { > > + if (blkdev->requests_total >= blkdev->max_requests) { > > goto out; > > } > > /* allocate new struct */ > > @@ -905,7 +907,7 @@ static void blk_handle_requests(struct XenBlkDev > *blkdev) > > ioreq_runio_qemu_aio(ioreq); > > } > > > > - if (blkdev->more_work && blkdev->requests_inflight < max_requests) { > > + if (blkdev->more_work && blkdev->requests_inflight < blkdev- > >max_requests) { > > qemu_bh_schedule(blkdev->bh); > > } > > } > > @@ -918,15 +920,6 @@ static void blk_bh(void *opaque) > > blk_handle_requests(blkdev); > > } > > > > -/* > > - * We need to account for the grant allocations requiring contiguous > > - * chunks; the worst case number would be > > - * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, > > - * but in order to keep things simple just use > > - * 2 * max_req * max_seg. > > - */ > > -#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) > > - > > static void blk_alloc(struct XenDevice *xendev) > > { > > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, > xendev); > > @@ -938,11 +931,6 @@ static void blk_alloc(struct XenDevice *xendev) > > if (xen_mode != XEN_EMULATE) { > > batch_maps = 1; > > } > > - if (xengnttab_set_max_grants(xendev->gnttabdev, > > - MAX_GRANTS(max_requests, > BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { > > - xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > > - strerror(errno)); > > - } > > } > > > > static void blk_parse_discard(struct XenBlkDev *blkdev) > > @@ -1037,6 +1025,9 @@ static int blk_init(struct XenDevice *xendev) > > !blkdev->feature_grant_copy); > > xenstore_write_be_int(&blkdev->xendev, "info", info); > > > > + xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order", > > + MAX_RING_PAGE_ORDER); > > + > > blk_parse_discard(blkdev); > > > > g_free(directiosafe); > > @@ -1058,12 +1049,25 @@ out_error: > > return -1; > > } > > > > +/* > > + * We need to account for the grant allocations requiring contiguous > > + * chunks; the worst case number would be > > + * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, > > + * but in order to keep things simple just use > > + * 2 * max_req * max_seg. > > + */ > > +#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) > > + > > static int blk_connect(struct XenDevice *xendev) > > { > > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, > xendev); > > int pers, index, qflags; > > bool readonly = true; > > bool writethrough = true; > > + int order, ring_ref; > > + unsigned int ring_size, max_grants; > > + unsigned int i; > > + uint32_t *domids; > > > > /* read-only ? */ > > if (blkdev->directiosafe) { > > @@ -1138,9 +1142,39 @@ static int blk_connect(struct XenDevice > *xendev) > > xenstore_write_be_int64(&blkdev->xendev, "sectors", > > blkdev->file_size / blkdev->file_blk); > > > > - if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev- > >ring_ref) == -1) { > > + if (xenstore_read_fe_int(&blkdev->xendev, "ring-page-order", > > + &order) == -1) { > > + blkdev->nr_ring_ref = 1; > > + > > + if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", > > + &ring_ref) == -1) { > > + return -1; > > + } > > + blkdev->ring_ref[0] = ring_ref; > > + > > + } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) { > > + blkdev->nr_ring_ref = 1 << order; > > + > > + for (i = 0; i < blkdev->nr_ring_ref; i++) { > > + char *key; > > + > > + key = g_strdup_printf("ring-ref%u", i); > > + if (!key) { > > + return -1; > > + } > > + > > + if (xenstore_read_fe_int(&blkdev->xendev, key, > > + &ring_ref) == -1) { > > it looks like we are leaking key. > Indeed it does. Good spot. > > > + return -1; > > + } > > + blkdev->ring_ref[i] = ring_ref; > > + > > + g_free(key); > > + } > > + } else { > > return -1; > > I would like to print warning if the requested ring size exceeds our > limit. > Sure. That's a good idea. Cheers, Paul > > > } > > + > > if (xenstore_read_fe_int(&blkdev->xendev, "event-channel", > > &blkdev->xendev.remote_port) == -1) { > > return -1; > > @@ -1163,41 +1197,85 @@ static int blk_connect(struct XenDevice > *xendev) > > blkdev->protocol = BLKIF_PROTOCOL_NATIVE; > > } > > > > - blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev, > > - blkdev->xendev.dom, > > - blkdev->ring_ref, > > - PROT_READ | PROT_WRITE); > > + ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref; > > + switch (blkdev->protocol) { > > + case BLKIF_PROTOCOL_NATIVE: > > + { > > + blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size); > > + break; > > + } > > + case BLKIF_PROTOCOL_X86_32: > > + { > > + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, > ring_size); > > + break; > > + } > > + case BLKIF_PROTOCOL_X86_64: > > + { > > + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, > ring_size); > > + break; > > + } > > + default: > > + return -1; > > + } > > + > > + /* Calculate the maximum number of grants needed by ioreqs */ > > + max_grants = MAX_GRANTS(blkdev->max_requests, > > + BLKIF_MAX_SEGMENTS_PER_REQUEST); > > + /* Add on the number needed for the ring pages */ > > + max_grants += blkdev->nr_ring_ref; > > + > > + if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, > max_grants)) { > > + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", > > + strerror(errno)); > > + return -1; > > + } > > + > > + domids = g_malloc0_n(blkdev->nr_ring_ref, sizeof(uint32_t)); > > + for (i = 0; i < blkdev->nr_ring_ref; i++) { > > + domids[i] = blkdev->xendev.dom; > > + } > > + > > + blkdev->sring = xengnttab_map_grant_refs(blkdev- > >xendev.gnttabdev, > > + blkdev->nr_ring_ref, > > + domids, > > + blkdev->ring_ref, > > + PROT_READ | PROT_WRITE); > > + > > + g_free(domids); > > + > > if (!blkdev->sring) { > > return -1; > > } > > + > > blkdev->cnt_map++; > > > > switch (blkdev->protocol) { > > case BLKIF_PROTOCOL_NATIVE: > > { > > blkif_sring_t *sring_native = blkdev->sring; > > - BACK_RING_INIT(&blkdev->rings.native, sring_native, > XC_PAGE_SIZE); > > + BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size); > > break; > > } > > case BLKIF_PROTOCOL_X86_32: > > { > > blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring; > > > > - BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, > XC_PAGE_SIZE); > > + BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, > ring_size); > > break; > > } > > case BLKIF_PROTOCOL_X86_64: > > { > > blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring; > > > > - BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, > XC_PAGE_SIZE); > > + BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, > ring_size); > > break; > > } > > } > > > > if (blkdev->feature_persistent) { > > /* Init persistent grants */ > > - blkdev->max_grants = max_requests * > BLKIF_MAX_SEGMENTS_PER_REQUEST; > > + blkdev->max_grants = blkdev->max_requests * > > + BLKIF_MAX_SEGMENTS_PER_REQUEST; > > blkdev->persistent_gnts = > g_tree_new_full((GCompareDataFunc)int_cmp, > > NULL, NULL, > > batch_maps ? > > @@ -1209,9 +1287,9 @@ static int blk_connect(struct XenDevice *xendev) > > > > xen_be_bind_evtchn(&blkdev->xendev); > > > > - xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " > > + xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, nr-ring-ref %u, " > > "remote port %d, local port %d\n", > > - blkdev->xendev.protocol, blkdev->ring_ref, > > + blkdev->xendev.protocol, blkdev->nr_ring_ref, > > blkdev->xendev.remote_port, blkdev->xendev.local_port); > > return 0; > > } > > @@ -1228,7 +1306,8 @@ static void blk_disconnect(struct XenDevice > *xendev) > > xen_pv_unbind_evtchn(&blkdev->xendev); > > > > if (blkdev->sring) { > > - xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); > > + xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, > > + blkdev->nr_ring_ref); > > blkdev->cnt_map--; > > blkdev->sring = NULL; > > } > > -- > > 2.11.0 > >
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 9b06e3aa81..a9942d32db 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -36,8 +36,6 @@ static int batch_maps = 0; -static int max_requests = 32; - /* ------------------------------------------------------------- */ #define BLOCK_SIZE 512 @@ -84,6 +82,8 @@ struct ioreq { BlockAcctCookie acct; }; +#define MAX_RING_PAGE_ORDER 4 + struct XenBlkDev { struct XenDevice xendev; /* must be first */ char *params; @@ -94,7 +94,8 @@ struct XenBlkDev { bool directiosafe; const char *fileproto; const char *filename; - int ring_ref; + unsigned int ring_ref[1 << MAX_RING_PAGE_ORDER]; + unsigned int nr_ring_ref; void *sring; int64_t file_blk; int64_t file_size; @@ -110,6 +111,7 @@ struct XenBlkDev { int requests_total; int requests_inflight; int requests_finished; + unsigned int max_requests; /* Persistent grants extension */ gboolean feature_discard; @@ -199,7 +201,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) struct ioreq *ioreq = NULL; if (QLIST_EMPTY(&blkdev->freelist)) { - if (blkdev->requests_total >= max_requests) { + if (blkdev->requests_total >= blkdev->max_requests) { goto out; } /* allocate new struct */ @@ -905,7 +907,7 @@ static void blk_handle_requests(struct XenBlkDev *blkdev) ioreq_runio_qemu_aio(ioreq); } - if (blkdev->more_work && blkdev->requests_inflight < max_requests) { + if (blkdev->more_work && blkdev->requests_inflight < blkdev->max_requests) { qemu_bh_schedule(blkdev->bh); } } @@ -918,15 +920,6 @@ static void blk_bh(void *opaque) blk_handle_requests(blkdev); } -/* - * We need to account for the grant allocations requiring contiguous - * chunks; the worst case number would be - * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, - * but in order to keep things simple just use - * 2 * max_req * max_seg. - */ -#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) - static void blk_alloc(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); @@ -938,11 +931,6 @@ static void blk_alloc(struct XenDevice *xendev) if (xen_mode != XEN_EMULATE) { batch_maps = 1; } - if (xengnttab_set_max_grants(xendev->gnttabdev, - MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { - xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", - strerror(errno)); - } } static void blk_parse_discard(struct XenBlkDev *blkdev) @@ -1037,6 +1025,9 @@ static int blk_init(struct XenDevice *xendev) !blkdev->feature_grant_copy); xenstore_write_be_int(&blkdev->xendev, "info", info); + xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order", + MAX_RING_PAGE_ORDER); + blk_parse_discard(blkdev); g_free(directiosafe); @@ -1058,12 +1049,25 @@ out_error: return -1; } +/* + * We need to account for the grant allocations requiring contiguous + * chunks; the worst case number would be + * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, + * but in order to keep things simple just use + * 2 * max_req * max_seg. + */ +#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) + static int blk_connect(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); int pers, index, qflags; bool readonly = true; bool writethrough = true; + int order, ring_ref; + unsigned int ring_size, max_grants; + unsigned int i; + uint32_t *domids; /* read-only ? */ if (blkdev->directiosafe) { @@ -1138,9 +1142,39 @@ static int blk_connect(struct XenDevice *xendev) xenstore_write_be_int64(&blkdev->xendev, "sectors", blkdev->file_size / blkdev->file_blk); - if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) { + if (xenstore_read_fe_int(&blkdev->xendev, "ring-page-order", + &order) == -1) { + blkdev->nr_ring_ref = 1; + + if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", + &ring_ref) == -1) { + return -1; + } + blkdev->ring_ref[0] = ring_ref; + + } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) { + blkdev->nr_ring_ref = 1 << order; + + for (i = 0; i < blkdev->nr_ring_ref; i++) { + char *key; + + key = g_strdup_printf("ring-ref%u", i); + if (!key) { + return -1; + } + + if (xenstore_read_fe_int(&blkdev->xendev, key, + &ring_ref) == -1) { + return -1; + } + blkdev->ring_ref[i] = ring_ref; + + g_free(key); + } + } else { return -1; } + if (xenstore_read_fe_int(&blkdev->xendev, "event-channel", &blkdev->xendev.remote_port) == -1) { return -1; @@ -1163,41 +1197,85 @@ static int blk_connect(struct XenDevice *xendev) blkdev->protocol = BLKIF_PROTOCOL_NATIVE; } - blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev, - blkdev->xendev.dom, - blkdev->ring_ref, - PROT_READ | PROT_WRITE); + ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref; + switch (blkdev->protocol) { + case BLKIF_PROTOCOL_NATIVE: + { + blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size); + break; + } + case BLKIF_PROTOCOL_X86_32: + { + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, ring_size); + break; + } + case BLKIF_PROTOCOL_X86_64: + { + blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, ring_size); + break; + } + default: + return -1; + } + + /* Calculate the maximum number of grants needed by ioreqs */ + max_grants = MAX_GRANTS(blkdev->max_requests, + BLKIF_MAX_SEGMENTS_PER_REQUEST); + /* Add on the number needed for the ring pages */ + max_grants += blkdev->nr_ring_ref; + + if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, max_grants)) { + xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n", + strerror(errno)); + return -1; + } + + domids = g_malloc0_n(blkdev->nr_ring_ref, sizeof(uint32_t)); + for (i = 0; i < blkdev->nr_ring_ref; i++) { + domids[i] = blkdev->xendev.dom; + } + + blkdev->sring = xengnttab_map_grant_refs(blkdev->xendev.gnttabdev, + blkdev->nr_ring_ref, + domids, + blkdev->ring_ref, + PROT_READ | PROT_WRITE); + + g_free(domids); + if (!blkdev->sring) { return -1; } + blkdev->cnt_map++; switch (blkdev->protocol) { case BLKIF_PROTOCOL_NATIVE: { blkif_sring_t *sring_native = blkdev->sring; - BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE); + BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size); break; } case BLKIF_PROTOCOL_X86_32: { blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring; - BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE); + BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, ring_size); break; } case BLKIF_PROTOCOL_X86_64: { blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring; - BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE); + BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, ring_size); break; } } if (blkdev->feature_persistent) { /* Init persistent grants */ - blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST; + blkdev->max_grants = blkdev->max_requests * + BLKIF_MAX_SEGMENTS_PER_REQUEST; blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp, NULL, NULL, batch_maps ? @@ -1209,9 +1287,9 @@ static int blk_connect(struct XenDevice *xendev) xen_be_bind_evtchn(&blkdev->xendev); - xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " + xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, nr-ring-ref %u, " "remote port %d, local port %d\n", - blkdev->xendev.protocol, blkdev->ring_ref, + blkdev->xendev.protocol, blkdev->nr_ring_ref, blkdev->xendev.remote_port, blkdev->xendev.local_port); return 0; } @@ -1228,7 +1306,8 @@ static void blk_disconnect(struct XenDevice *xendev) xen_pv_unbind_evtchn(&blkdev->xendev); if (blkdev->sring) { - xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); + xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, + blkdev->nr_ring_ref); blkdev->cnt_map--; blkdev->sring = NULL; }
The blkif protocol has had provision for negotiation of multi-page shared rings for some time now and many guest OS have support in their frontend drivers. This patch makes the necessary modifications to xen-disk support a shared ring up to order 4 (i.e. 16 pages). Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> --- hw/block/xen_disk.c | 141 ++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 110 insertions(+), 31 deletions(-)