Re: vhost-user technical isssues

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

Hi Lin,

(2014/11/14 13:42), Linhaifeng wrote:
>
> On 2014/11/14 11:40, Tetsuya Mukawa wrote:
>> 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,
>
> How many is size? mmap_size + mmap_offset ?
In this case, guest memory length is the size.
I added messages from this program within last email.
Could you please also check it?

>
>
>> 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);
> memory.regions[i].memory_size --> memory.regions[i].memory_size + memory.regions[i].memory_offset
>
> check you have apply qemu's patch: [PATCH] vhost-user: fix mmap offset calculation
I checked it using latest QEMU code.
So the patch you mentioned is included.

I guess you can munmap a file, because 'size' is aligned by hugepage
size like 2GB.
Could you please try another value like 6000MB?

Thanks,
Tetsuya