linux-kernel - Re: [PATCH v33 0/4] Virtio-balloon: support free page reporting

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180615172933-mutt-send-email-mst@kernel.org>
Date:   Fri, 15 Jun 2018 17:38:31 +0300
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     "Wang, Wei W" <wei.w.wang@...el.com>
Cc:     "virtio-dev@...ts.oasis-open.org" <virtio-dev@...ts.oasis-open.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "mhocko@...nel.org" <mhocko@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "liliang.opensource@...il.com" <liliang.opensource@...il.com>,
        "yang.zhang.wz@...il.com" <yang.zhang.wz@...il.com>,
        "quan.xu0@...il.com" <quan.xu0@...il.com>,
        "nilal@...hat.com" <nilal@...hat.com>,
        "riel@...hat.com" <riel@...hat.com>,
        "peterx@...hat.com" <peterx@...hat.com>
Subject: Re: [PATCH v33 0/4] Virtio-balloon: support free page reporting

On Fri, Jun 15, 2018 at 02:28:49PM +0000, Wang, Wei W wrote:
> On Friday, June 15, 2018 7:30 PM, Michael S. Tsirkin wrote:
> > On Fri, Jun 15, 2018 at 12:43:09PM +0800, Wei Wang wrote:
> > >       - remove the cmd id related interface. Now host can just send a free
> > >         page hint command to the guest (via the host_cmd config register)
> > >         to start the reporting.
> > 
> > Here we go again. And what if reporting was already started previously?
> > I don't think it's a good idea to tweak the host/guest interface yet again.
> 
> This interface is much simpler, and I'm not sure if that would be an
> issue here now, because now the guest delivers the whole buffer of
> hints to host once, instead of hint by hint as before. And the guest
> notifies host after the buffer is delivered. In any case, the host
> doorbell handler will be invoked, if host doesn't need the hints at
> that time, it will just give back the buffer. There will be no stale
> hints remained in the ring now.
> 
> Best,
> Wei

I still think all the old arguments for cmd id apply.

-- 
MST