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Date: Wed, 17 Sep 2014 17:39:04 +0800
From: Linhaifeng <haifeng.lin@huawei.com>
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Subject: Re: [Qemu-devel] vhost-user: VHOST_SET_MEM_TABLE,
 VHOST_SET_VRING_CALL need a reply?
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, n.nikolaev@virtualopensystems.com, jerry.lilijun@huawei.com

I think maybe is not need for the backend to wait for response.

There is another way.vhost-user send "VHOST_GET_MEM_TABLE" to qemu then qemu send VHOST_SET_MEM_TABLE to update the regions of vhost-user.same as other command.
If qemu could response the request of the vhost-user.the vhost-user could update date at anytime.

I think it's very useful for Commercialization.

On 2014/9/17 16:38, Michael S. Tsirkin wrote:
> Reply-To: 
> 
> Thinking about the vhost-user protocol, VHOST_SET_MEM_TABLE
> is used to update the memory mappings.
> 
> So shouldn't we want for response?
> Otherwise e.g. guest can start using the memory
> that vhost-user can't access.
> 
> Similarly, with an IOMMU vhost-user might access memory it shouldn't.
> 
> VHOST_SET_VRING_CALL is used for MSI-X masking.
> Again, after vector is masted by switching the call fd,
> backend shouldn't assert the old one.
> 
> Thoughts?
> 
>