From 875b9fd97b34dae796d61330804b094ca7b1b403 Mon Sep 17 00:00:00 2001 From: Raphael Norwitz Date: Thu, 21 May 2020 05:00:56 +0000 Subject: Support individual region unmap in libvhost-user When the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS protocol feature is enabled, on memory hot-unplug qemu will transmit memory regions to remove individually using the new message VHOST_USER_REM_MEM_REG message. With this change, vhost-user backends build with libvhost-user can now unmap individual memory regions when receiving the VHOST_USER_REM_MEM_REG message. Qemu only sends VHOST_USER_REM_MEM_REG messages when the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS feature is negotiated, and support for that feature has not yet been added in libvhost-user, this new functionality is not yet used. Signed-off-by: Raphael Norwitz Message-Id: <1588533678-23450-10-git-send-email-raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- contrib/libvhost-user/libvhost-user.c | 63 +++++++++++++++++++++++++++++++++++ contrib/libvhost-user/libvhost-user.h | 1 + 2 files changed, 64 insertions(+) (limited to 'contrib/libvhost-user') diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c index d8ee7a23a3..386449b697 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -139,6 +139,7 @@ vu_request_to_string(unsigned int req) REQ(VHOST_USER_VRING_KICK), REQ(VHOST_USER_GET_MAX_MEM_SLOTS), REQ(VHOST_USER_ADD_MEM_REG), + REQ(VHOST_USER_REM_MEM_REG), REQ(VHOST_USER_MAX), }; #undef REQ @@ -763,6 +764,66 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { } } +static inline bool reg_equal(VuDevRegion *vudev_reg, + VhostUserMemoryRegion *msg_reg) +{ + if (vudev_reg->gpa == msg_reg->guest_phys_addr && + vudev_reg->qva == msg_reg->userspace_addr && + vudev_reg->size == msg_reg->memory_size) { + return true; + } + + return false; +} + +static bool +vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) { + int i, j; + bool found = false; + VuDevRegion shadow_regions[VHOST_MEMORY_MAX_NREGIONS] = {}; + VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m; + + DPRINT("Removing region:\n"); + DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n", + msg_region->guest_phys_addr); + DPRINT(" memory_size: 0x%016"PRIx64"\n", + msg_region->memory_size); + DPRINT(" userspace_addr 0x%016"PRIx64"\n", + msg_region->userspace_addr); + DPRINT(" mmap_offset 0x%016"PRIx64"\n", + msg_region->mmap_offset); + + for (i = 0, j = 0; i < dev->nregions; i++) { + if (!reg_equal(&dev->regions[i], msg_region)) { + shadow_regions[j].gpa = dev->regions[i].gpa; + shadow_regions[j].size = dev->regions[i].size; + shadow_regions[j].qva = dev->regions[i].qva; + shadow_regions[j].mmap_offset = dev->regions[i].mmap_offset; + j++; + } else { + found = true; + VuDevRegion *r = &dev->regions[i]; + void *m = (void *) (uintptr_t) r->mmap_addr; + + if (m) { + munmap(m, r->size + r->mmap_offset); + } + } + } + + if (found) { + memcpy(dev->regions, shadow_regions, + sizeof(VuDevRegion) * VHOST_MEMORY_MAX_NREGIONS); + DPRINT("Successfully removed a region\n"); + dev->nregions--; + vmsg_set_reply_u64(vmsg, 0); + } else { + vu_panic(dev, "Specified region not found\n"); + } + + return true; +} + static bool vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) { @@ -1771,6 +1832,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg) return vu_handle_get_max_memslots(dev, vmsg); case VHOST_USER_ADD_MEM_REG: return vu_add_mem_reg(dev, vmsg); + case VHOST_USER_REM_MEM_REG: + return vu_rem_mem_reg(dev, vmsg); default: vmsg_close_fds(vmsg); vu_panic(dev, "Unhandled request: %d", vmsg->request); diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h index 60ef7fd13e..f8439713a8 100644 --- a/contrib/libvhost-user/libvhost-user.h +++ b/contrib/libvhost-user/libvhost-user.h @@ -99,6 +99,7 @@ typedef enum VhostUserRequest { VHOST_USER_VRING_KICK = 35, VHOST_USER_GET_MAX_MEM_SLOTS = 36, VHOST_USER_ADD_MEM_REG = 37, + VHOST_USER_REM_MEM_REG = 38, VHOST_USER_MAX } VhostUserRequest; -- cgit v1.2.3