From 1ff7c5986a515d2d936eba026ff19947bbc7cb92 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Wed, 3 May 2017 14:00:35 -0700 Subject: xen/mapcache: store dma information in revmapcache entries for debugging The Xen mapcache is able to create long term mappings, they are called "locked" mappings. The third parameter of the xen_map_cache call specifies if a mapping is a "locked" mapping. >From the QEMU point of view there are two kinds of long term mappings: [a] device memory mappings, such as option roms and video memory [b] dma mappings, created by dma_memory_map & friends After certain operations, ballooning a VM in particular, Xen asks QEMU kindly to destroy all mappings. However, certainly [a] mappings are present and cannot be removed. That's not a problem as they are not affected by balloonning. The *real* problem is that if there are any mappings of type [b], any outstanding dma operations could fail. This is a known shortcoming. In other words, when Xen asks QEMU to destroy all mappings, it is an error if any [b] mappings exist. However today we have no way of distinguishing [a] from [b]. Because of that, we cannot even print a decent warning. This patch introduces a new "dma" bool field to MapCacheRev entires, to remember if a given mapping is for dma or is a long term device memory mapping. When xen_invalidate_map_cache is called, we print a warning if any [b] mappings exist. We ignore [a] mappings. Mappings created by qemu_map_ram_ptr are assumed to be [a], while mappings created by address_space_map->qemu_ram_ptr_length are assumed to be [b]. The goal of the patch is to make debugging and system understanding easier. Signed-off-by: Stefano Stabellini Acked-by: Paolo Bonzini Acked-by: Anthony PERARD --- exec.c | 8 ++++---- hw/i386/xen/xen-mapcache.c | 15 ++++++++++----- include/sysemu/xen-mapcache.h | 5 +++-- 3 files changed, 17 insertions(+), 11 deletions(-) diff --git a/exec.c b/exec.c index eac6085760..85769e1464 100644 --- a/exec.c +++ b/exec.c @@ -2084,10 +2084,10 @@ void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr) * In that case just map until the end of the page. */ if (block->offset == 0) { - return xen_map_cache(addr, 0, 0); + return xen_map_cache(addr, 0, 0, false); } - block->host = xen_map_cache(block->offset, block->max_length, 1); + block->host = xen_map_cache(block->offset, block->max_length, 1, false); } return ramblock_ptr(block, addr); } @@ -2117,10 +2117,10 @@ static void *qemu_ram_ptr_length(RAMBlock *ram_block, ram_addr_t addr, * In that case just map the requested area. */ if (block->offset == 0) { - return xen_map_cache(addr, *size, 1); + return xen_map_cache(addr, *size, 1, true); } - block->host = xen_map_cache(block->offset, block->max_length, 1); + block->host = xen_map_cache(block->offset, block->max_length, 1, true); } return ramblock_ptr(block, addr); diff --git a/hw/i386/xen/xen-mapcache.c b/hw/i386/xen/xen-mapcache.c index 31debdfb2c..e60156c04f 100644 --- a/hw/i386/xen/xen-mapcache.c +++ b/hw/i386/xen/xen-mapcache.c @@ -62,6 +62,7 @@ typedef struct MapCacheRev { hwaddr paddr_index; hwaddr size; QTAILQ_ENTRY(MapCacheRev) next; + bool dma; } MapCacheRev; typedef struct MapCache { @@ -202,7 +203,7 @@ static void xen_remap_bucket(MapCacheEntry *entry, } static uint8_t *xen_map_cache_unlocked(hwaddr phys_addr, hwaddr size, - uint8_t lock) + uint8_t lock, bool dma) { MapCacheEntry *entry, *pentry = NULL; hwaddr address_index; @@ -289,6 +290,7 @@ tryagain: if (lock) { MapCacheRev *reventry = g_malloc0(sizeof(MapCacheRev)); entry->lock++; + reventry->dma = dma; reventry->vaddr_req = mapcache->last_entry->vaddr_base + address_offset; reventry->paddr_index = mapcache->last_entry->paddr_index; reventry->size = entry->size; @@ -300,12 +302,12 @@ tryagain: } uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, - uint8_t lock) + uint8_t lock, bool dma) { uint8_t *p; mapcache_lock(); - p = xen_map_cache_unlocked(phys_addr, size, lock); + p = xen_map_cache_unlocked(phys_addr, size, lock, dma); mapcache_unlock(); return p; } @@ -426,8 +428,11 @@ void xen_invalidate_map_cache(void) mapcache_lock(); QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) { - DPRINTF("There should be no locked mappings at this time, " - "but "TARGET_FMT_plx" -> %p is present\n", + if (!reventry->dma) { + continue; + } + fprintf(stderr, "Locked DMA mapping while invalidating mapcache!" + " "TARGET_FMT_plx" -> %p is present\n", reventry->paddr_index, reventry->vaddr_req); } diff --git a/include/sysemu/xen-mapcache.h b/include/sysemu/xen-mapcache.h index b8c93b9bce..01daaad00c 100644 --- a/include/sysemu/xen-mapcache.h +++ b/include/sysemu/xen-mapcache.h @@ -17,7 +17,7 @@ typedef hwaddr (*phys_offset_to_gaddr_t)(hwaddr start_addr, void xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque); uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, - uint8_t lock); + uint8_t lock, bool dma); ram_addr_t xen_ram_addr_from_mapcache(void *ptr); void xen_invalidate_map_cache_entry(uint8_t *buffer); void xen_invalidate_map_cache(void); @@ -31,7 +31,8 @@ static inline void xen_map_cache_init(phys_offset_to_gaddr_t f, static inline uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, - uint8_t lock) + uint8_t lock, + bool dma) { abort(); } -- cgit v1.2.3 From d9506cab36391c906671b3767d0ccf9c8c0e9645 Mon Sep 17 00:00:00 2001 From: Anthony PERARD Date: Thu, 11 May 2017 12:35:42 +0100 Subject: configure: Remove -lxencall for Xen detection QEMU does not depends on libxencall, it was added because it was a missing link dependency of libxendevicemodel, but now the later should be built properly. Signed-off-by: Anthony PERARD Reviewed-by: Stefano Stabellini --- configure | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/configure b/configure index 57b5ae600b..139638e922 100755 --- a/configure +++ b/configure @@ -2015,7 +2015,7 @@ if test "$xen" != "no" ; then else xen_libs="-lxenstore -lxenctrl -lxenguest" - xen_stable_libs="-lxencall -lxenforeignmemory -lxengnttab -lxenevtchn" + xen_stable_libs="-lxenforeignmemory -lxengnttab -lxenevtchn" # First we test whether Xen headers and libraries are available. # If no, we are done and there is no Xen support. -- cgit v1.2.3 From c0c24b95542bc1a4dc3fc6ea71475ae04fa69189 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Tue, 9 May 2017 12:04:51 -0700 Subject: xen/9pfs: fix two resource leaks on error paths, discovered by Coverity CID: 1374836 Signed-off-by: Stefano Stabellini Reviewed-by: Eric Blake Reviewed-by: Greg Kurz CC: anthony.perard@citrix.com CC: groug@kaod.org CC: aneesh.kumar@linux.vnet.ibm.com --- hw/9pfs/xen-9p-backend.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c index 9c7f41af99..a1fdedecc6 100644 --- a/hw/9pfs/xen-9p-backend.c +++ b/hw/9pfs/xen-9p-backend.c @@ -332,12 +332,14 @@ static int xen_9pfs_connect(struct XenDevice *xendev) str = g_strdup_printf("ring-ref%u", i); if (xenstore_read_fe_int(&xen_9pdev->xendev, str, &xen_9pdev->rings[i].ref) == -1) { + g_free(str); goto out; } g_free(str); str = g_strdup_printf("event-channel-%u", i); if (xenstore_read_fe_int(&xen_9pdev->xendev, str, &xen_9pdev->rings[i].evtchn) == -1) { + g_free(str); goto out; } g_free(str); -- cgit v1.2.3 From 01cd90b641e1aed40cf13a577e6a737af94d55e7 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Tue, 9 May 2017 12:04:53 -0700 Subject: xen: call qemu_set_cloexec instead of fcntl Use the common utility function, which contains checks on return values and first calls F_GETFD as recommended by POSIX.1-2001, instead of manually calling fcntl. CID: 1374831 Signed-off-by: Stefano Stabellini Reviewed-by: Eric Blake Reviewed-by: Greg Kurz CC: anthony.perard@citrix.com CC: groug@kaod.org CC: aneesh.kumar@linux.vnet.ibm.com CC: Eric Blake --- hw/9pfs/xen-9p-backend.c | 2 +- hw/xen/xen_backend.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c index a1fdedecc6..5df97c90fa 100644 --- a/hw/9pfs/xen-9p-backend.c +++ b/hw/9pfs/xen-9p-backend.c @@ -380,7 +380,7 @@ static int xen_9pfs_connect(struct XenDevice *xendev) if (xen_9pdev->rings[i].evtchndev == NULL) { goto out; } - fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD, FD_CLOEXEC); + qemu_set_cloexec(xenevtchn_fd(xen_9pdev->rings[i].evtchndev)); xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain (xen_9pdev->rings[i].evtchndev, xendev->dom, diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c index c85f1637e4..2cac47d6c4 100644 --- a/hw/xen/xen_backend.c +++ b/hw/xen/xen_backend.c @@ -147,7 +147,7 @@ static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev, qdev_unplug(DEVICE(xendev), NULL); return NULL; } - fcntl(xenevtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC); + qemu_set_cloexec(xenevtchn_fd(xendev->evtchndev)); if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) { xendev->gnttabdev = xengnttab_open(NULL, 0); -- cgit v1.2.3