diff options
| -rw-r--r-- | subprojects/libvhost-user/libvhost-user.c | 107 |
1 files changed, 78 insertions, 29 deletions
diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c index ed0a978d4f..61fb3050b3 100644 --- a/subprojects/libvhost-user/libvhost-user.c +++ b/subprojects/libvhost-user/libvhost-user.c @@ -284,9 +284,74 @@ vu_remove_all_mem_regs(VuDev *dev) } static bool +map_ring(VuDev *dev, VuVirtq *vq) +{ + vq->vring.desc = qva_to_va(dev, vq->vra.desc_user_addr); + vq->vring.used = qva_to_va(dev, vq->vra.used_user_addr); + vq->vring.avail = qva_to_va(dev, vq->vra.avail_user_addr); + + DPRINT("Setting virtq addresses:\n"); + DPRINT(" vring_desc at %p\n", vq->vring.desc); + DPRINT(" vring_used at %p\n", vq->vring.used); + DPRINT(" vring_avail at %p\n", vq->vring.avail); + + return !(vq->vring.desc && vq->vring.used && vq->vring.avail); +} + +static bool vu_is_vq_usable(VuDev *dev, VuVirtq *vq) { - return likely(!dev->broken) && likely(vq->vring.avail); + if (unlikely(dev->broken)) { + return false; + } + + if (likely(vq->vring.avail)) { + return true; + } + + /* + * In corner cases, we might temporarily remove a memory region that + * mapped a ring. When removing a memory region we make sure to + * unmap any rings that would be impacted. Let's try to remap if we + * already succeeded mapping this ring once. + */ + if (!vq->vra.desc_user_addr || !vq->vra.used_user_addr || + !vq->vra.avail_user_addr) { + return false; + } + if (map_ring(dev, vq)) { + vu_panic(dev, "remapping queue on access"); + return false; + } + return true; +} + +static void +unmap_rings(VuDev *dev, VuDevRegion *r) +{ + int i; + + for (i = 0; i < dev->max_queues; i++) { + VuVirtq *vq = &dev->vq[i]; + const uintptr_t desc = (uintptr_t)vq->vring.desc; + const uintptr_t used = (uintptr_t)vq->vring.used; + const uintptr_t avail = (uintptr_t)vq->vring.avail; + + if (desc < r->mmap_addr || desc >= r->mmap_addr + r->size) { + continue; + } + if (used < r->mmap_addr || used >= r->mmap_addr + r->size) { + continue; + } + if (avail < r->mmap_addr || avail >= r->mmap_addr + r->size) { + continue; + } + + DPRINT("Unmapping rings of queue %d\n", i); + vq->vring.desc = NULL; + vq->vring.used = NULL; + vq->vring.avail = NULL; + } } static size_t @@ -787,21 +852,6 @@ vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg) } static bool -map_ring(VuDev *dev, VuVirtq *vq) -{ - vq->vring.desc = qva_to_va(dev, vq->vra.desc_user_addr); - vq->vring.used = qva_to_va(dev, vq->vra.used_user_addr); - vq->vring.avail = qva_to_va(dev, vq->vra.avail_user_addr); - - DPRINT("Setting virtq addresses:\n"); - DPRINT(" vring_desc at %p\n", vq->vring.desc); - DPRINT(" vring_used at %p\n", vq->vring.used); - DPRINT(" vring_avail at %p\n", vq->vring.avail); - - return !(vq->vring.desc && vq->vring.used && vq->vring.avail); -} - -static bool generate_faults(VuDev *dev) { unsigned int i; for (i = 0; i < dev->nregions; i++) { @@ -884,7 +934,6 @@ generate_faults(VuDev *dev) { static bool vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { - int i; VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m; if (vmsg->fd_num != 1) { @@ -930,19 +979,9 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { vmsg->fd_num = 0; DPRINT("Successfully added new region in postcopy\n"); return true; - } else { - for (i = 0; i < dev->max_queues; i++) { - if (dev->vq[i].vring.desc) { - if (map_ring(dev, &dev->vq[i])) { - vu_panic(dev, "remapping queue %d for new memory region", - i); - } - } - } - - DPRINT("Successfully added new region\n"); - return false; } + DPRINT("Successfully added new region\n"); + return false; } static inline bool reg_equal(VuDevRegion *vudev_reg, @@ -995,6 +1034,16 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { return false; } + /* + * There might be valid cases where we temporarily remove memory regions + * to readd them again, or remove memory regions and don't use the rings + * anymore before we set the ring addresses and restart the device. + * + * Unmap all affected rings, remapping them on demand later. This should + * be a corner case. + */ + unmap_rings(dev, r); + munmap((void *)(uintptr_t)r->mmap_addr, r->size + r->mmap_offset); idx = r - dev->regions; |