[PATCH openEuler-1.0-LTS 1/6] xen/blkfront: fix memory allocation flags in blkfront_setup_indirect()
From: Juergen Gross <jgross@suse.com> stable inclusion from stable-v4.19.116 commit 5f547e7cbd8435be3aa2a27e2ae594b4fd94865b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GLXT CVE: CVE-2022-26365 -------------------------------- commit 3a169c0be75b59dd85d159493634870cdec6d3c4 upstream. Commit 1d5c76e664333 ("xen-blkfront: switch kcalloc to kvcalloc for large array allocation") didn't fix the issue it was meant to, as the flags for allocating the memory are GFP_NOIO, which will lead the memory allocation falling back to kmalloc(). So instead of GFP_NOIO use GFP_KERNEL and do all the memory allocation in blkfront_setup_indirect() in a memalloc_noio_{save,restore} section. Fixes: 1d5c76e664333 ("xen-blkfront: switch kcalloc to kvcalloc for large array allocation") Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20200403090034.8753-1-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/block/xen-blkfront.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 0e451b17f33a..8059ff5ab4a6 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -47,6 +47,7 @@ #include <linux/bitmap.h> #include <linux/list.h> #include <linux/workqueue.h> +#include <linux/sched/mm.h> #include <xen/xen.h> #include <xen/xenbus.h> @@ -2251,10 +2252,12 @@ static void blkfront_setup_discard(struct blkfront_info *info) static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) { - unsigned int psegs, grants; + unsigned int psegs, grants, memflags; int err, i; struct blkfront_info *info = rinfo->dev_info; + memflags = memalloc_noio_save(); + if (info->max_indirect_segments == 0) { if (!HAS_EXTRA_REQ) grants = BLKIF_MAX_SEGMENTS_PER_REQUEST; @@ -2286,7 +2289,7 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) BUG_ON(!list_empty(&rinfo->indirect_pages)); for (i = 0; i < num; i++) { - struct page *indirect_page = alloc_page(GFP_NOIO); + struct page *indirect_page = alloc_page(GFP_KERNEL); if (!indirect_page) goto out_of_memory; list_add(&indirect_page->lru, &rinfo->indirect_pages); @@ -2297,15 +2300,15 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) rinfo->shadow[i].grants_used = kvcalloc(grants, sizeof(rinfo->shadow[i].grants_used[0]), - GFP_NOIO); + GFP_KERNEL); rinfo->shadow[i].sg = kvcalloc(psegs, sizeof(rinfo->shadow[i].sg[0]), - GFP_NOIO); + GFP_KERNEL); if (info->max_indirect_segments) rinfo->shadow[i].indirect_grants = kvcalloc(INDIRECT_GREFS(grants), sizeof(rinfo->shadow[i].indirect_grants[0]), - GFP_NOIO); + GFP_KERNEL); if ((rinfo->shadow[i].grants_used == NULL) || (rinfo->shadow[i].sg == NULL) || (info->max_indirect_segments && @@ -2314,6 +2317,7 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) sg_init_table(rinfo->shadow[i].sg, psegs); } + memalloc_noio_restore(memflags); return 0; @@ -2333,6 +2337,9 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) __free_page(indirect_page); } } + + memalloc_noio_restore(memflags); + return -ENOMEM; } -- 2.25.1
From: Roger Pau Monne <roger.pau@citrix.com> stable inclusion from stable-v4.19.251 commit f4a1391185e30c977bfe1648435c152f806211c7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GLXT CVE: CVE-2022-26365 -------------------------------- commit 2f446ffe9d737e9a844b97887919c4fda18246e7 upstream. When allocating pages to be used for shared communication with the backend always zero them, this avoids leaking unintended data present on the pages. This is CVE-2022-26365, part of XSA-403. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/block/xen-blkfront.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 8059ff5ab4a6..5863e742b4c9 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -301,7 +301,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) goto out_of_memory; if (info->feature_persistent) { - granted_page = alloc_page(GFP_NOIO); + granted_page = alloc_page(GFP_NOIO | __GFP_ZERO); if (!granted_page) { kfree(gnt_list_entry); goto out_of_memory; @@ -1743,7 +1743,7 @@ static int setup_blkring(struct xenbus_device *dev, for (i = 0; i < info->nr_ring_pages; i++) rinfo->ring_ref[i] = GRANT_INVALID_REF; - sring = alloc_pages_exact(ring_size, GFP_NOIO); + sring = alloc_pages_exact(ring_size, GFP_NOIO | __GFP_ZERO); if (!sring) { xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); return -ENOMEM; @@ -2289,7 +2289,8 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) BUG_ON(!list_empty(&rinfo->indirect_pages)); for (i = 0; i < num; i++) { - struct page *indirect_page = alloc_page(GFP_KERNEL); + struct page *indirect_page = alloc_page(GFP_KERNEL | + __GFP_ZERO); if (!indirect_page) goto out_of_memory; list_add(&indirect_page->lru, &rinfo->indirect_pages); -- 2.25.1
From: Roger Pau Monne <roger.pau@citrix.com> stable inclusion from stable-v4.19.251 commit 3650ac3218c1640a3d597a8cee17d8e2fcf0ed4e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GLYP CVE: CVE-2022-33740 -------------------------------- commit 307c8de2b02344805ebead3440d8feed28f2f010 upstream. When allocating pages to be used for shared communication with the backend always zero them, this avoids leaking unintended data present on the pages. This is CVE-2022-33740, part of XSA-403. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/net/xen-netfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 376024c26270..1d1d63af368d 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -259,7 +259,7 @@ static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue) if (unlikely(!skb)) return NULL; - page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); + page = alloc_page(GFP_ATOMIC | __GFP_NOWARN | __GFP_ZERO); if (!page) { kfree_skb(skb); return NULL; -- 2.25.1
From: Andrea Righi <andrea.righi@canonical.com> stable inclusion from stable-v4.19.137 commit 4b635fc2b3491bdaa69fd80b376b216fae2d1461 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GLZZ CVE: CVE-2022-33741 -------------------------------- [ Upstream commit c2c633106453611be07821f53dff9e93a9d1c3f0 ] There's a potential race in xennet_remove(); this is what the driver is doing upon unregistering a network device: 1. state = read bus state 2. if state is not "Closed": 3. request to set state to "Closing" 4. wait for state to be set to "Closing" 5. request to set state to "Closed" 6. wait for state to be set to "Closed" If the state changes to "Closed" immediately after step 1 we are stuck forever in step 4, because the state will never go back from "Closed" to "Closing". Make sure to check also for state == "Closed" in step 4 to prevent the deadlock. Also add a 5 sec timeout any time we wait for the bus state to change, to avoid getting stuck forever in wait_event(). Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/net/xen-netfront.c | 64 +++++++++++++++++++++++++------------- 1 file changed, 42 insertions(+), 22 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 1d1d63af368d..892e540f2d92 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -63,6 +63,8 @@ module_param_named(max_queues, xennet_max_queues, uint, 0644); MODULE_PARM_DESC(max_queues, "Maximum number of queues per virtual interface"); +#define XENNET_TIMEOUT (5 * HZ) + static const struct ethtool_ops xennet_ethtool_ops; struct netfront_cb { @@ -1452,12 +1454,15 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev) netif_carrier_off(netdev); - xenbus_switch_state(dev, XenbusStateInitialising); - wait_event(module_wq, - xenbus_read_driver_state(dev->otherend) != - XenbusStateClosed && - xenbus_read_driver_state(dev->otherend) != - XenbusStateUnknown); + do { + xenbus_switch_state(dev, XenbusStateInitialising); + err = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) != + XenbusStateClosed && + xenbus_read_driver_state(dev->otherend) != + XenbusStateUnknown, XENNET_TIMEOUT); + } while (!err); + return netdev; exit: @@ -2270,28 +2275,43 @@ static const struct attribute_group xennet_dev_group = { }; #endif /* CONFIG_SYSFS */ -static int xennet_remove(struct xenbus_device *dev) +static void xennet_bus_close(struct xenbus_device *dev) { - struct netfront_info *info = dev_get_drvdata(&dev->dev); - - dev_dbg(&dev->dev, "%s\n", dev->nodename); + int ret; - if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) { + if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed) + return; + do { xenbus_switch_state(dev, XenbusStateClosing); - wait_event(module_wq, - xenbus_read_driver_state(dev->otherend) == - XenbusStateClosing || - xenbus_read_driver_state(dev->otherend) == - XenbusStateUnknown); + ret = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosing || + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosed || + xenbus_read_driver_state(dev->otherend) == + XenbusStateUnknown, + XENNET_TIMEOUT); + } while (!ret); + + if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed) + return; + do { xenbus_switch_state(dev, XenbusStateClosed); - wait_event(module_wq, - xenbus_read_driver_state(dev->otherend) == - XenbusStateClosed || - xenbus_read_driver_state(dev->otherend) == - XenbusStateUnknown); - } + ret = wait_event_timeout(module_wq, + xenbus_read_driver_state(dev->otherend) == + XenbusStateClosed || + xenbus_read_driver_state(dev->otherend) == + XenbusStateUnknown, + XENNET_TIMEOUT); + } while (!ret); +} + +static int xennet_remove(struct xenbus_device *dev) +{ + struct netfront_info *info = dev_get_drvdata(&dev->dev); + xennet_bus_close(dev); xennet_disconnect_backend(info); if (info->netdev->reg_state == NETREG_REGISTERED) -- 2.25.1
From: Roger Pau Monne <roger.pau@citrix.com> stable inclusion from stable-v4.19.251 commit 4b67d8e42dbba42cfafe22ac3e4117d9573fdd74 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GM0S CVE: CVE-2022-33741 -------------------------------- commit 4491001c2e0fa69efbb748c96ec96b100a5cdb7e upstream. Bounce all data on the skbs to be transmitted into zeroed pages if the backend is untrusted. This avoids leaking data present in the pages shared with the backend but not part of the skb fragments. This requires introducing a new helper in order to allocate skbs with a size multiple of XEN_PAGE_SIZE so we don't leak contiguous data on the granted pages. Reporting whether the backend is to be trusted can be done using a module parameter, or from the xenstore frontend path as set by the toolstack when adding the device. This is CVE-2022-33741, part of XSA-403. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/net/xen-netfront.c | 50 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 48 insertions(+), 2 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 892e540f2d92..f5f11346427e 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -63,6 +63,10 @@ module_param_named(max_queues, xennet_max_queues, uint, 0644); MODULE_PARM_DESC(max_queues, "Maximum number of queues per virtual interface"); +static bool __read_mostly xennet_trusted = true; +module_param_named(trusted, xennet_trusted, bool, 0644); +MODULE_PARM_DESC(trusted, "Is the backend trusted"); + #define XENNET_TIMEOUT (5 * HZ) static const struct ethtool_ops xennet_ethtool_ops; @@ -163,6 +167,9 @@ struct netfront_info { /* Is device behaving sane? */ bool broken; + /* Should skbs be bounced into a zeroed buffer? */ + bool bounce; + atomic_t rx_gso_checksum_fixup; }; @@ -593,6 +600,34 @@ static void xennet_mark_tx_pending(struct netfront_queue *queue) queue->tx_link[i] = TX_PENDING; } +struct sk_buff *bounce_skb(const struct sk_buff *skb) +{ + unsigned int headerlen = skb_headroom(skb); + /* Align size to allocate full pages and avoid contiguous data leaks */ + unsigned int size = ALIGN(skb_end_offset(skb) + skb->data_len, + XEN_PAGE_SIZE); + struct sk_buff *n = alloc_skb(size, GFP_ATOMIC | __GFP_ZERO); + + if (!n) + return NULL; + + if (!IS_ALIGNED((uintptr_t)n->head, XEN_PAGE_SIZE)) { + WARN_ONCE(1, "misaligned skb allocated\n"); + kfree_skb(n); + return NULL; + } + + /* Set the data pointer */ + skb_reserve(n, headerlen); + /* Set the tail pointer and length */ + skb_put(n, skb->len); + + BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)); + + skb_copy_header(n, skb); + return n; +} + #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1) static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) @@ -645,9 +680,13 @@ static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev /* The first req should be at least ETH_HLEN size or the packet will be * dropped by netback. + * + * If the backend is not trusted bounce all data to zeroed pages to + * avoid exposing contiguous data on the granted page not belonging to + * the skb. */ - if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) { - nskb = skb_copy(skb, GFP_ATOMIC); + if (np->bounce || unlikely(PAGE_SIZE - offset < ETH_HLEN)) { + nskb = bounce_skb(skb); if (!nskb) goto drop; dev_consume_skb_any(skb); @@ -1942,6 +1981,10 @@ static int talk_to_netback(struct xenbus_device *dev, info->netdev->irq = 0; + /* Check if backend is trusted. */ + info->bounce = !xennet_trusted || + !xenbus_read_unsigned(dev->nodename, "trusted", 1); + /* Check if backend supports multiple queues */ max_queues = xenbus_read_unsigned(info->xbdev->otherend, "multi-queue-max-queues", 1); @@ -2095,6 +2138,9 @@ static int xennet_connect(struct net_device *dev) err = talk_to_netback(np->xbdev, np); if (err) return err; + if (np->bounce) + dev_info(&np->xbdev->dev, + "bouncing transmitted data to zeroed pages\n"); /* talk_to_netback() sets the correct number of queues */ num_queues = dev->real_num_tx_queues; -- 2.25.1
From: Roger Pau Monne <roger.pau@citrix.com> stable inclusion from stable-v4.19.251 commit 981de55fb6b5253fa7ae345827c6c3ca77912e5c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5GM0S CVE: CVE-2022-33742 -------------------------------- commit 2400617da7eebf9167d71a46122828bc479d64c9 upstream. Split the current bounce buffering logic used with persistent grants into it's own option, and allow enabling it independently of persistent grants. This allows to reuse the same code paths to perform the bounce buffering required to avoid leaking contiguous data in shared pages not part of the request fragments. Reporting whether the backend is to be trusted can be done using a module parameter, or from the xenstore frontend path as set by the toolstack when adding the device. This is CVE-2022-33742, part of XSA-403. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/block/xen-blkfront.c | 49 +++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 15 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 5863e742b4c9..bc1d350c9bdc 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -151,6 +151,10 @@ static unsigned int xen_blkif_max_ring_order; module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444); MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); +static bool __read_mostly xen_blkif_trusted = true; +module_param_named(trusted, xen_blkif_trusted, bool, 0644); +MODULE_PARM_DESC(trusted, "Is the backend trusted"); + #define BLK_RING_SIZE(info) \ __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) @@ -211,6 +215,7 @@ struct blkfront_info unsigned int feature_discard:1; unsigned int feature_secdiscard:1; unsigned int feature_persistent:1; + unsigned int bounce:1; unsigned int discard_granularity; unsigned int discard_alignment; /* Number of 4KB segments handled */ @@ -300,7 +305,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) if (!gnt_list_entry) goto out_of_memory; - if (info->feature_persistent) { + if (info->bounce) { granted_page = alloc_page(GFP_NOIO | __GFP_ZERO); if (!granted_page) { kfree(gnt_list_entry); @@ -320,7 +325,7 @@ static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num) list_for_each_entry_safe(gnt_list_entry, n, &rinfo->grants, node) { list_del(&gnt_list_entry->node); - if (info->feature_persistent) + if (info->bounce) __free_page(gnt_list_entry->page); kfree(gnt_list_entry); i--; @@ -366,7 +371,7 @@ static struct grant *get_grant(grant_ref_t *gref_head, /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); - if (info->feature_persistent) + if (info->bounce) grant_foreign_access(gnt_list_entry, info); else { /* Grant access to the GFN passed by the caller */ @@ -390,7 +395,7 @@ static struct grant *get_indirect_grant(grant_ref_t *gref_head, /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); - if (!info->feature_persistent) { + if (!info->bounce) { struct page *indirect_page; /* Fetch a pre-allocated page to use for indirect grefs */ @@ -705,7 +710,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri .grant_idx = 0, .segments = NULL, .rinfo = rinfo, - .need_copy = rq_data_dir(req) && info->feature_persistent, + .need_copy = rq_data_dir(req) && info->bounce, }; /* @@ -1025,11 +1030,12 @@ static void xlvbd_flush(struct blkfront_info *info) { blk_queue_write_cache(info->rq, info->feature_flush ? true : false, info->feature_fua ? true : false); - pr_info("blkfront: %s: %s %s %s %s %s\n", + pr_info("blkfront: %s: %s %s %s %s %s %s %s\n", info->gd->disk_name, flush_info(info), "persistent grants:", info->feature_persistent ? "enabled;" : "disabled;", "indirect descriptors:", - info->max_indirect_segments ? "enabled;" : "disabled;"); + info->max_indirect_segments ? "enabled;" : "disabled;", + "bounce buffer:", info->bounce ? "enabled" : "disabled;"); } static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) @@ -1264,7 +1270,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) if (!list_empty(&rinfo->indirect_pages)) { struct page *indirect_page, *n; - BUG_ON(info->feature_persistent); + BUG_ON(info->bounce); list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) { list_del(&indirect_page->lru); __free_page(indirect_page); @@ -1281,7 +1287,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) 0, 0UL); rinfo->persistent_gnts_c--; } - if (info->feature_persistent) + if (info->bounce) __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1302,7 +1308,7 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) for (j = 0; j < segs; j++) { persistent_gnt = rinfo->shadow[i].grants_used[j]; gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); - if (info->feature_persistent) + if (info->bounce) __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1492,7 +1498,7 @@ static int blkif_completion(unsigned long *id, data.s = s; num_sg = s->num_sg; - if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { + if (bret->operation == BLKIF_OP_READ && info->bounce) { for_each_sg(s->sg, sg, num_sg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); @@ -1551,7 +1557,7 @@ static int blkif_completion(unsigned long *id, * Add the used indirect page back to the list of * available pages for indirect grefs. */ - if (!info->feature_persistent) { + if (!info->bounce) { indirect_page = s->indirect_grants[i]->page; list_add(&indirect_page->lru, &rinfo->indirect_pages); } @@ -1846,6 +1852,10 @@ static int talk_to_blkback(struct xenbus_device *dev, if (!info) return -ENODEV; + /* Check if backend is trusted. */ + info->bounce = !xen_blkif_trusted || + !xenbus_read_unsigned(dev->nodename, "trusted", 1); + max_page_order = xenbus_read_unsigned(info->xbdev->otherend, "max-ring-page-order", 0); ring_page_order = min(xen_blkif_max_ring_order, max_page_order); @@ -2279,10 +2289,10 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo) if (err) goto out_of_memory; - if (!info->feature_persistent && info->max_indirect_segments) { + if (!info->bounce && info->max_indirect_segments) { /* - * We are using indirect descriptors but not persistent - * grants, we need to allocate a set of pages that can be + * We are using indirect descriptors but don't have a bounce + * buffer, we need to allocate a set of pages that can be * used for mapping indirect grefs */ int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); @@ -2382,6 +2392,8 @@ static void blkfront_gather_backend_features(struct blkfront_info *info) info->feature_persistent = !!xenbus_read_unsigned(info->xbdev->otherend, "feature-persistent", 0); + if (info->feature_persistent) + info->bounce = true; indirect_segments = xenbus_read_unsigned(info->xbdev->otherend, "feature-max-indirect-segments", 0); @@ -2757,6 +2769,13 @@ static void blkfront_delay_work(struct work_struct *work) struct blkfront_info *info; bool need_schedule_work = false; + /* + * Note that when using bounce buffers but not persistent grants + * there's no need to run blkfront_delay_work because grants are + * revoked in blkif_completion or else an error is reported and the + * connection is closed. + */ + mutex_lock(&blkfront_mutex); list_for_each_entry(info, &info_list, info_list) { -- 2.25.1
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Yongqiang Liu