Re: vhost-user technical isssues

[Tetsuya Mukawa <mukawa-AlSX/UN32fvPDbFq/vQRIQ@public.gmane.org>]

Hi Lin,

(2014/11/14 12:13), Linhaifeng wrote:
>
> size should be same as mmap and
> guest_mem -= (memory.regions[i].mmap_offset / sizeof(*guest_mem));
>

Thanks. It should be.
How about following patch?

-------------------------------------------------------
diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index 75fedf0..be4b171 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -37,7 +37,7 @@
#endif

#define QEMU_CMD_ACCEL " -machine accel=tcg"
-#define QEMU_CMD_MEM " -m 512 -object
memory-backend-file,id=mem,size=512M,"\
+#define QEMU_CMD_MEM " -m 6000 -object
memory-backend-file,id=mem,size=6000M,"\
"mem-path=%s,share=on -numa node,memdev=mem"
#define QEMU_CMD_CHR " -chardev socket,id=chr0,path=%s"
#define QEMU_CMD_NETDEV " -netdev
vhost-user,id=net0,chardev=chr0,vhostforce"
@@ -221,13 +221,16 @@ static void read_guest_mem(void)

/* check for sanity */
g_assert_cmpint(fds_num, >, 0);
- g_assert_cmpint(fds_num, ==, memory.nregions);
+ //g_assert_cmpint(fds_num, ==, memory.nregions);

+ fprintf(stderr, "%s(%d)\n", __func__, __LINE__);
/* iterate all regions */
for (i = 0; i < fds_num; i++) {
+ int ret = 0;

/* We'll check only the region statring at 0x0*/
- if (memory.regions[i].guest_phys_addr != 0x0) {
+ if (memory.regions[i].guest_phys_addr == 0x0) {
+ close(fds[i]);
continue;
}

@@ -237,6 +240,7 @@ static void read_guest_mem(void)

guest_mem = mmap(0, size, PROT_READ | PROT_WRITE,
MAP_SHARED, fds[i], 0);
+ fprintf(stderr, "region=%d, mmap=%p, size=%lu\n", i, guest_mem, size);

g_assert(guest_mem != MAP_FAILED);
guest_mem += (memory.regions[i].mmap_offset / sizeof(*guest_mem));
@@ -247,8 +251,10 @@ static void read_guest_mem(void)

g_assert_cmpint(a, ==, b);
}
-
- munmap(guest_mem, memory.regions[i].memory_size);
+ guest_mem -= (memory.regions[i].mmap_offset / sizeof(*guest_mem));
+ ret = munmap(guest_mem, memory.regions[i].memory_size);
+ fprintf(stderr, "region=%d, munmap=%p, size=%lu, ret=%d\n",
+ i, guest_mem, size, ret);
}

g_assert_cmpint(1, ==, 1);
-------------------------------------------------------
I am using 1GB hugepage size.

$ sudo QTEST_HUGETLBFS_PATH=/mnt/huge make check
region=0, mmap=0x2aaac0000000, size=6291456000
region=0, munmap=0x2aaac0000000, size=6291456000, ret=-1 << failed

6291456000 is not aligned by 1GB.
When I specify 4096MB as guest memory size, munmap() doesn't return
error like following.

$ sudo QTEST_HUGETLBFS_PATH=/mnt/huge make check
region=0, mmap=0x2aaac0000000, size=4294967296
region=0, munmap=0x2aaac0000000, size=4294967296, ret=0

Thanks,
Tetsuya