diff options
Diffstat (limited to 'contrib/libvhost-user/libvhost-user.c')
| -rw-r--r-- | contrib/libvhost-user/libvhost-user.c | 47 |
1 files changed, 42 insertions, 5 deletions
diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c index 6314549b65..5feed52098 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -454,7 +454,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) int i; VhostUserMemory *memory = &vmsg->payload.memory; dev->nregions = memory->nregions; - /* TODO: Postcopy specific code */ + DPRINT("Nregions: %d\n", memory->nregions); for (i = 0; i < dev->nregions; i++) { void *mmap_addr; @@ -478,9 +478,12 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) /* We don't use offset argument of mmap() since the * mapped address has to be page aligned, and we use huge - * pages. */ + * pages. + * In postcopy we're using PROT_NONE here to catch anyone + * accessing it before we userfault + */ mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset, - PROT_READ | PROT_WRITE, MAP_SHARED, + PROT_NONE, MAP_SHARED, vmsg->fds[i], 0); if (mmap_addr == MAP_FAILED) { @@ -519,12 +522,38 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) /* OK, now we can go and register the memory and generate faults */ for (i = 0; i < dev->nregions; i++) { VuDevRegion *dev_region = &dev->regions[i]; + int ret; #ifdef UFFDIO_REGISTER /* We should already have an open ufd. Mark each memory * range as ufd. - * Note: Do we need any madvises? Well it's not been accessed - * yet, still probably need no THP to be safe, discard to be safe? + * Discard any mapping we have here; note I can't use MADV_REMOVE + * or fallocate to make the hole since I don't want to lose + * data that's already arrived in the shared process. + * TODO: How to do hugepage */ + ret = madvise((void *)dev_region->mmap_addr, + dev_region->size + dev_region->mmap_offset, + MADV_DONTNEED); + if (ret) { + fprintf(stderr, + "%s: Failed to madvise(DONTNEED) region %d: %s\n", + __func__, i, strerror(errno)); + } + /* Turn off transparent hugepages so we dont get lose wakeups + * in neighbouring pages. + * TODO: Turn this backon later. + */ + ret = madvise((void *)dev_region->mmap_addr, + dev_region->size + dev_region->mmap_offset, + MADV_NOHUGEPAGE); + if (ret) { + /* Note: This can happen legally on kernels that are configured + * without madvise'able hugepages + */ + fprintf(stderr, + "%s: Failed to madvise(NOHUGEPAGE) region %d: %s\n", + __func__, i, strerror(errno)); + } struct uffdio_register reg_struct; reg_struct.range.start = (uintptr_t)dev_region->mmap_addr; reg_struct.range.len = dev_region->size + dev_region->mmap_offset; @@ -546,6 +575,14 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) } DPRINT("%s: region %d: Registered userfault for %llx + %llx\n", __func__, i, reg_struct.range.start, reg_struct.range.len); + /* Now it's registered we can let the client at it */ + if (mprotect((void *)dev_region->mmap_addr, + dev_region->size + dev_region->mmap_offset, + PROT_READ | PROT_WRITE)) { + vu_panic(dev, "failed to mprotect region %d for postcopy (%s)", + i, strerror(errno)); + return false; + } /* TODO: Stash 'zero' support flags somewhere */ #endif } |