diff mbox

[v1,1/2] vhost-user: support SET_MEM_TABLE waite the result of mmap

Message ID 1423547293-8448-1-git-send-email-haifeng.lin@huawei.com
State New
Headers show

Commit Message

Linhaifeng Feb. 10, 2015, 5:48 a.m. UTC 
From: Linhaifeng <haifeng.lin@huawei.com>

Slave should reply to master and set u64 to 0 if
mmap all regions success otherwise set u64 to 1.

Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
---
 docs/specs/vhost-user.txt | 1 +
 1 file changed, 1 insertion(+)

Comments

Michael S. Tsirkin Feb. 10, 2015, 8:46 a.m. UTC | #1 
On Tue, Feb 10, 2015 at 01:48:12PM +0800, linhaifeng wrote:
> From: Linhaifeng <haifeng.lin@huawei.com>
> 
> Slave should reply to master and set u64 to 0 if
> mmap all regions success otherwise set u64 to 1.
> 
> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>

How does this work with existig slaves though?

> ---
>  docs/specs/vhost-user.txt | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 650bb18..c96bf6b 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -171,6 +171,7 @@ Message types
>        Id: 5
>        Equivalent ioctl: VHOST_SET_MEM_TABLE
>        Master payload: memory regions description
> +      Slave payload: u64 (0:success >0:failed)
>  
>        Sets the memory map regions on the slave so it can translate the vring
>        addresses. In the ancillary data there is an array of file descriptors
> -- 
> 1.7.12.4
>
Linhaifeng Feb. 10, 2015, 10:27 a.m. UTC | #2 
On 2015/2/10 16:46, Michael S. Tsirkin wrote:
> On Tue, Feb 10, 2015 at 01:48:12PM +0800, linhaifeng wrote:
>> From: Linhaifeng <haifeng.lin@huawei.com>
>>
>> Slave should reply to master and set u64 to 0 if
>> mmap all regions success otherwise set u64 to 1.
>>
>> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
> 
> How does this work with existig slaves though?
> 

Slaves should work like this:

int set_mem_table(...)
{
    ....
    for (idx = 0, i = 0; idx < memory.nregions; idx++) {
	....
    	mem = mmap(..);
	if (MAP_FAILED == mem) {
		msg->msg.u64 = 1;
                msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
		return 1;
	}
    }

    ....

    msg->msg.u64 = 0;
    msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
    return 1;
}

If slaves not reply QEMU will always wait.

>> ---
>>  docs/specs/vhost-user.txt | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
>> index 650bb18..c96bf6b 100644
>> --- a/docs/specs/vhost-user.txt
>> +++ b/docs/specs/vhost-user.txt
>> @@ -171,6 +171,7 @@ Message types
>>        Id: 5
>>        Equivalent ioctl: VHOST_SET_MEM_TABLE
>>        Master payload: memory regions description
>> +      Slave payload: u64 (0:success >0:failed)
>>  
>>        Sets the memory map regions on the slave so it can translate the vring
>>        addresses. In the ancillary data there is an array of file descriptors
>> -- 
>> 1.7.12.4
>>
> 
>
Michael S. Tsirkin Feb. 10, 2015, 10:41 a.m. UTC | #3 
On Tue, Feb 10, 2015 at 06:27:04PM +0800, Linhaifeng wrote:
> 
> 
> On 2015/2/10 16:46, Michael S. Tsirkin wrote:
> > On Tue, Feb 10, 2015 at 01:48:12PM +0800, linhaifeng wrote:
> >> From: Linhaifeng <haifeng.lin@huawei.com>
> >>
> >> Slave should reply to master and set u64 to 0 if
> >> mmap all regions success otherwise set u64 to 1.
> >>
> >> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
> > 
> > How does this work with existig slaves though?
> > 
> 
> Slaves should work like this:
> 
> int set_mem_table(...)
> {
>     ....
>     for (idx = 0, i = 0; idx < memory.nregions; idx++) {
> 	....
>     	mem = mmap(..);
> 	if (MAP_FAILED == mem) {
> 		msg->msg.u64 = 1;
>                 msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
> 		return 1;
> 	}
>     }
> 
>     ....
> 
>     msg->msg.u64 = 0;
>     msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
>     return 1;
> }
> 
> If slaves not reply QEMU will always wait.

Are you sure existing slaves reply?

> >> ---
> >>  docs/specs/vhost-user.txt | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> >> index 650bb18..c96bf6b 100644
> >> --- a/docs/specs/vhost-user.txt
> >> +++ b/docs/specs/vhost-user.txt
> >> @@ -171,6 +171,7 @@ Message types
> >>        Id: 5
> >>        Equivalent ioctl: VHOST_SET_MEM_TABLE
> >>        Master payload: memory regions description
> >> +      Slave payload: u64 (0:success >0:failed)
> >>  
> >>        Sets the memory map regions on the slave so it can translate the vring
> >>        addresses. In the ancillary data there is an array of file descriptors
> >> -- 
> >> 1.7.12.4
> >>
> > 
> > 
> 
> -- 
> Regards,
> Haifeng
Linhaifeng Feb. 10, 2015, 11:59 a.m. UTC | #4 
On 2015/2/10 18:41, Michael S. Tsirkin wrote:
> On Tue, Feb 10, 2015 at 06:27:04PM +0800, Linhaifeng wrote:
>>
>>
>> On 2015/2/10 16:46, Michael S. Tsirkin wrote:
>>> On Tue, Feb 10, 2015 at 01:48:12PM +0800, linhaifeng wrote:
>>>> From: Linhaifeng <haifeng.lin@huawei.com>
>>>>
>>>> Slave should reply to master and set u64 to 0 if
>>>> mmap all regions success otherwise set u64 to 1.
>>>>
>>>> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
>>>
>>> How does this work with existig slaves though?
>>>
>>
>> Slaves should work like this:
>>
>> int set_mem_table(...)
>> {
>>     ....
>>     for (idx = 0, i = 0; idx < memory.nregions; idx++) {
>> 	....
>>     	mem = mmap(..);
>> 	if (MAP_FAILED == mem) {
>> 		msg->msg.u64 = 1;
>>                 msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
>> 		return 1;
>> 	}
>>     }
>>
>>     ....
>>
>>     msg->msg.u64 = 0;
>>     msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
>>     return 1;
>> }
>>
>> If slaves not reply QEMU will always wait.
> 
> Are you sure existing slaves reply?

No.May be the existing slaves need add reply in their codes.

> 
>>>> ---
>>>>  docs/specs/vhost-user.txt | 1 +
>>>>  1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
>>>> index 650bb18..c96bf6b 100644
>>>> --- a/docs/specs/vhost-user.txt
>>>> +++ b/docs/specs/vhost-user.txt
>>>> @@ -171,6 +171,7 @@ Message types
>>>>        Id: 5
>>>>        Equivalent ioctl: VHOST_SET_MEM_TABLE
>>>>        Master payload: memory regions description
>>>> +      Slave payload: u64 (0:success >0:failed)
>>>>  
>>>>        Sets the memory map regions on the slave so it can translate the vring
>>>>        addresses. In the ancillary data there is an array of file descriptors
>>>> -- 
>>>> 1.7.12.4
>>>>
>>>
>>>
>>
>> -- 
>> Regards,
>> Haifeng
> 
> .
>
Michael S. Tsirkin Feb. 10, 2015, 12:04 p.m. UTC | #5 
On Tue, Feb 10, 2015 at 07:59:16PM +0800, Linhaifeng wrote:
> 
> 
> On 2015/2/10 18:41, Michael S. Tsirkin wrote:
> > On Tue, Feb 10, 2015 at 06:27:04PM +0800, Linhaifeng wrote:
> >>
> >>
> >> On 2015/2/10 16:46, Michael S. Tsirkin wrote:
> >>> On Tue, Feb 10, 2015 at 01:48:12PM +0800, linhaifeng wrote:
> >>>> From: Linhaifeng <haifeng.lin@huawei.com>
> >>>>
> >>>> Slave should reply to master and set u64 to 0 if
> >>>> mmap all regions success otherwise set u64 to 1.
> >>>>
> >>>> Signed-off-by: Linhaifeng <haifeng.lin@huawei.com>
> >>>
> >>> How does this work with existig slaves though?
> >>>
> >>
> >> Slaves should work like this:
> >>
> >> int set_mem_table(...)
> >> {
> >>     ....
> >>     for (idx = 0, i = 0; idx < memory.nregions; idx++) {
> >> 	....
> >>     	mem = mmap(..);
> >> 	if (MAP_FAILED == mem) {
> >> 		msg->msg.u64 = 1;
> >>                 msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
> >> 		return 1;
> >> 	}
> >>     }
> >>
> >>     ....
> >>
> >>     msg->msg.u64 = 0;
> >>     msg->msg.size = MEMB_SIZE(VhostUserMsg, u64);
> >>     return 1;
> >> }
> >>
> >> If slaves not reply QEMU will always wait.
> > 
> > Are you sure existing slaves reply?
> 
> No.May be the existing slaves need add reply in their codes.

So that's not good. We need a way to negotiate the capability,
we can't just deadlock with legacy slaves.

> > 
> >>>> ---
> >>>>  docs/specs/vhost-user.txt | 1 +
> >>>>  1 file changed, 1 insertion(+)
> >>>>
> >>>> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> >>>> index 650bb18..c96bf6b 100644
> >>>> --- a/docs/specs/vhost-user.txt
> >>>> +++ b/docs/specs/vhost-user.txt
> >>>> @@ -171,6 +171,7 @@ Message types
> >>>>        Id: 5
> >>>>        Equivalent ioctl: VHOST_SET_MEM_TABLE
> >>>>        Master payload: memory regions description
> >>>> +      Slave payload: u64 (0:success >0:failed)
> >>>>  
> >>>>        Sets the memory map regions on the slave so it can translate the vring
> >>>>        addresses. In the ancillary data there is an array of file descriptors
> >>>> -- 
> >>>> 1.7.12.4
> >>>>
> >>>
> >>>
> >>
> >> -- 
> >> Regards,
> >> Haifeng
> > 
> > .
> > 
> 
> -- 
> Regards,
> Haifeng
Linhaifeng Feb. 11, 2015, 1:38 a.m. UTC | #6 
On 2015/2/10 20:04, Michael S. Tsirkin wrote:
> So that's not good. We need a way to negotiate the capability,
> we can't just deadlock with legacy slaves.

Should we wait many seconds if slave not reply we just return error?
Linhaifeng Feb. 11, 2015, 6:30 a.m. UTC | #7 
On 2015/2/10 20:04, Michael S. Tsirkin wrote:
> So that's not good. We need a way to negotiate the capability,
> we can't just deadlock with legacy slaves.

Or add a new message to query slaves' version if slaves not reply we don't wait
otherwise if the version as same as QEMU we wait the reply.

Mostly the same as iotcl may be all messages need reply.
Linhaifeng Feb. 12, 2015, 3:25 a.m. UTC | #8 
>>
>> No.May be the existing slaves need add reply in their codes.
> 
> So that's not good. We need a way to negotiate the capability,
> we can't just deadlock with legacy slaves.
> 

Hi,Michael

Do you have any suggestions?
Michael S. Tsirkin Feb. 12, 2015, 4:38 p.m. UTC | #9 
On Wed, Feb 11, 2015 at 09:38:34AM +0800, Linhaifeng wrote:
> 
> 
> On 2015/2/10 20:04, Michael S. Tsirkin wrote:
> > So that's not good. We need a way to negotiate the capability,
> > we can't just deadlock with legacy slaves.
> 
> Should we wait many seconds if slave not reply we just return error?

I would prefer something more robust.
Isn't there a version field we can use?

> -- 
> Regards,
> Haifeng
diff mbox

Patch

diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 650bb18..c96bf6b 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -171,6 +171,7 @@  Message types
       Id: 5
       Equivalent ioctl: VHOST_SET_MEM_TABLE
       Master payload: memory regions description
+      Slave payload: u64 (0:success >0:failed)
 
       Sets the memory map regions on the slave so it can translate the vring
       addresses. In the ancillary data there is an array of file descriptors