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libvhost-user: Factor out adding a memory region 

Let's factor it out, reducing quite some code duplication and perparing
for further changes.

If we fail to mmap a region and panic, we now simply don't add that
(broken) region.

Note that we now increment dev->nregions as we are successfully
adding memory regions, and don't increment dev->nregions if anything went
wrong.

Reviewed-by: Raphael Norwitz <raphael@enfabrica.net>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20240214151701.29906-6-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
David Hildenbrand 2024-02-14 16:16:52 +01:00 committed by Michael S. Tsirkin
parent 05a58ce471
commit 93fec23d8c
1 changed files with 60 additions and 108 deletions
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168
subprojects/libvhost-user/libvhost-user.c
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@ -256,6 +256,61 @@ vu_remove_all_mem_regs(VuDev *dev)
dev->nregions = 0;
}
static void
_vu_add_mem_reg(VuDev *dev, VhostUserMemoryRegion *msg_region, int fd)
{
int prot = PROT_READ | PROT_WRITE;
VuDevRegion *r;
void *mmap_addr;
DPRINT("Adding region %d\n", dev->nregions);
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);
if (dev->postcopy_listening) {
/*
* In postcopy we're using PROT_NONE here to catch anyone
* accessing it before we userfault
*/
prot = PROT_NONE;
}
/*
* We don't use offset argument of mmap() since the mapped address has
* to be page aligned, and we use huge pages.
*/
mmap_addr = mmap(0, msg_region->memory_size + msg_region->mmap_offset,
prot, MAP_SHARED | MAP_NORESERVE, fd, 0);
if (mmap_addr == MAP_FAILED) {
vu_panic(dev, "region mmap error: %s", strerror(errno));
return;
}
DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
(uint64_t)(uintptr_t)mmap_addr);
r = &dev->regions[dev->nregions];
r->gpa = msg_region->guest_phys_addr;
r->size = msg_region->memory_size;
r->qva = msg_region->userspace_addr;
r->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
r->mmap_offset = msg_region->mmap_offset;
dev->nregions++;
if (dev->postcopy_listening) {
/*
* Return the address to QEMU so that it can translate the ufd
* fault addresses back.
*/
msg_region->userspace_addr = r->mmap_addr + r->mmap_offset;
}
}
static void
vmsg_close_fds(VhostUserMsg *vmsg)
{
@ -727,10 +782,7 @@ generate_faults(VuDev *dev) {
static bool
vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
int i;
bool track_ramblocks = dev->postcopy_listening;
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
VuDevRegion *dev_region = &dev->regions[dev->nregions];
void *mmap_addr;
if (vmsg->fd_num != 1) {
vmsg_close_fds(vmsg);
@ -760,69 +812,20 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
* we know all the postcopy client bases have been received, and we
* should start generating faults.
*/
if (track_ramblocks &&
if (dev->postcopy_listening &&
vmsg->size == sizeof(vmsg->payload.u64) &&
vmsg->payload.u64 == 0) {
(void)generate_faults(dev);
return false;
}
DPRINT("Adding region: %u\n", dev->nregions);
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);
dev_region->gpa = msg_region->guest_phys_addr;
dev_region->size = msg_region->memory_size;
dev_region->qva = msg_region->userspace_addr;
dev_region->mmap_offset = msg_region->mmap_offset;
/*
* We don't use offset argument of mmap() since the
* mapped address has to be page aligned, and we use huge
* pages.
*/
if (track_ramblocks) {
/*
* 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_NONE, MAP_SHARED | MAP_NORESERVE,
vmsg->fds[0], 0);
} else {
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE,
vmsg->fds[0], 0);
}
if (mmap_addr == MAP_FAILED) {
vu_panic(dev, "region mmap error: %s", strerror(errno));
} else {
dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
dev_region->mmap_addr);
}
_vu_add_mem_reg(dev, msg_region, vmsg->fds[0]);
close(vmsg->fds[0]);
if (track_ramblocks) {
/*
* Return the address to QEMU so that it can translate the ufd
* fault addresses back.
*/
msg_region->userspace_addr = (uintptr_t)(mmap_addr +
dev_region->mmap_offset);
if (dev->postcopy_listening) {
/* Send the message back to qemu with the addresses filled in. */
vmsg->fd_num = 0;
DPRINT("Successfully added new region in postcopy\n");
dev->nregions++;
return true;
} else {
for (i = 0; i < dev->max_queues; i++) {
@ -835,7 +838,6 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
}
DPRINT("Successfully added new region\n");
dev->nregions++;
return false;
}
}
@ -940,63 +942,13 @@ static bool
vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
{
VhostUserMemory m = vmsg->payload.memory, *memory = &m;
int prot = PROT_READ | PROT_WRITE;
unsigned int i;
if (dev->postcopy_listening) {
/*
* In postcopy we're using PROT_NONE here to catch anyone
* accessing it before we userfault
*/
prot = PROT_NONE;
}
vu_remove_all_mem_regs(dev);
dev->nregions = memory->nregions;
DPRINT("Nregions: %u\n", memory->nregions);
for (i = 0; i < dev->nregions; i++) {
void *mmap_addr;
VhostUserMemoryRegion *msg_region = &memory->regions[i];
VuDevRegion *dev_region = &dev->regions[i];
DPRINT("Region %d\n", i);
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);
dev_region->gpa = msg_region->guest_phys_addr;
dev_region->size = msg_region->memory_size;
dev_region->qva = msg_region->userspace_addr;
dev_region->mmap_offset = msg_region->mmap_offset;
/* We don't use offset argument of mmap() since the
* mapped address has to be page aligned, and we use huge
* pages. */
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
prot, MAP_SHARED | MAP_NORESERVE, vmsg->fds[i], 0);
if (mmap_addr == MAP_FAILED) {
vu_panic(dev, "region mmap error: %s", strerror(errno));
} else {
dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
dev_region->mmap_addr);
}
if (dev->postcopy_listening) {
/*
* Return the address to QEMU so that it can translate the ufd
* fault addresses back.
*/
msg_region->userspace_addr = (uintptr_t)(mmap_addr +
dev_region->mmap_offset);
}
for (i = 0; i < memory->nregions; i++) {
_vu_add_mem_reg(dev, &memory->regions[i], vmsg->fds[i]);
close(vmsg->fds[i]);
}