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Support individual region unmap in libvhost-user

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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 <raphael.norwitz@nutanix.com>
Message-Id: <1588533678-23450-10-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Raphael Norwitz 2020-05-21 05:00:56 +00:00 committed by Michael S. Tsirkin
parent ec94c8e621
commit 875b9fd97b
2 changed files with 64 additions and 0 deletions
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63
contrib/libvhost-user/libvhost-user.c
View File

@ -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);

1
contrib/libvhost-user/libvhost-user.h
View File

@ -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;