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[Qemu-devel] vhost-user question
From: |
jack.chen |
Subject: |
[Qemu-devel] vhost-user question |
Date: |
Wed, 31 Jan 2018 19:42:10 +0800 |
hello,I am confused when I read vhost-user source code in qemu.I know
vhost-user app shared memory with qemu by mmap,but why it can use fd which
is belong to qemu?
relative code:
qemu code in function vhost_user_set_mem_table
fd = memory_region_get_fd(mr);
if (fd > 0) {
msg.payload.memory.regions[fd_num].userspace_addr =
reg->userspace_addr;
msg.payload.memory.regions[fd_num].memory_size =
reg->memory_size;
msg.payload.memory.regions[fd_num].guest_phys_addr =
reg->guest_phys_addr;
msg.payload.memory.regions[fd_num].mmap_offset = offset;
assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
fds[fd_num++] = fd;
}
……
DPDK code in vhost_user_set_mem_table
mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_POPULATE, fd, 0);
……
thanks a lot!
- [Qemu-devel] vhost-user question,
jack.chen <=