<html dir="ltr"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <style>  </style><style type="text/css" id="owaParaStyle"></style> </head> <body fpstyle="1" ocsi="0"> <div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;"> <div>Hi Alain,</div> <div><br> </div> <div>Could you please point to some of the Greg's proposals?</div> <div><br> </div> <div>Thanks in advance.</div> <div><br> </div> <div>Best regards,<br> Dmitry.<br> </div> <div><br> </div> <div style="font-family: Times New Roman; color: #000000; font-size: 16px"> <hr tabindex="-1"> <div id="divRpF736864" style="direction: ltr;"><font size="2" face="Tahoma" color="#000000"><b>From:</b> virglrenderer-devel [virglrenderer-devel-bounces@lists.freedesktop.org] on behalf of Alain Magloire [amagloire@blackberry.com]<br> <b>Sent:</b> Thursday, August 20, 2020 01:18<br> <b>To:</b> Chia-I Wu; Vasyl Vavrychuk<br> <b>Cc:</b> virglrenderer-devel<br> <b>Subject:</b> Re: [virglrenderer-devel] virgl_renderer_resource_import_eglimage<br> </font><br> </div> <div></div> <div><style type="text/css" style="">  </style> <div dir="ltr"> <div id="x_divtagdefaultwrapper" dir="ltr" style="font-size:12pt; color:#000000; font-family:Calibri,Helvetica,sans-serif"> <p>Bonjour,</p> <p><br> </p> <p>Yes, it is my understanding that virtio-gpu allocates memory on the guest.</p> <p>Then on the host you will have the corresponding backing store... <br> </p> <p>if synchronization is needed, then you will get a transfer Host to guest and vice-versa and your performance is.. not great.</p> <p>The transfer to the attach backing is basically a memcpyv().<br> </p> <p><br> </p> <p>On Android, it can get more challenging, as Android is not killing apps, but relying on the lmkd (low memory killer) to take actions...</p> <p>Except that the graphics memory being consumed by guest... is actually on the host... sigh... the accounting is off.</p> <p><br> </p> <p>They are different possible strategies to deal with this.</p> <p>Gerd H proposed a few...</p> <p><br> </p> <p>Thanks<br> </p> <p><br> </p> <p><br> </p> <p><br> </p> </div> <hr tabindex="-1" style="display:inline-block; width:98%"> <div id="x_divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> virglrenderer-devel <virglrenderer-devel-bounces@lists.freedesktop.org> on behalf of Chia-I Wu <olvaffe@gmail.com><br> <b>Sent:</b> Wednesday, August 19, 2020 6:40:38 PM<br> <b>To:</b> Vasyl Vavrychuk<br> <b>Cc:</b> virglrenderer-devel<br> <b>Subject:</b> Re: [virglrenderer-devel] virgl_renderer_resource_import_eglimage</font> <div> </div> </div> </div> <font size="2"><span style="font-size:10pt"> <div class="PlainText">On Wed, Aug 19, 2020 at 3:12 PM Vasyl Vavrychuk <vvavrychuk@gmail.com> wrote:<br> ><br> > On Wed, Aug 19, 2020 at 10:02 PM Chia-I Wu <olvaffe@gmail.com> wrote:<br> > ><br> > > On Wed, Aug 19, 2020 at 1:42 AM Vasyl Vavrychuk <vvavrychuk@gmail.com> wrote:<br> > > ><br> > > > Commit message for commit that adds "virgl_renderer_resource_import_eglimage" says this function supposed to be used from CrosVM. But I have checked CrosVM source and did not find virgl_renderer_resource_import_eglimage usage. Same for QEMU.<br> > > ><br> > > > As I understand virgl_renderer_resource_import_eglimage is essential to achieve zero copy. So, why QEMU/CrosVM do not use it. Are they using some other methods to achieve zero copy?<br> > ><br> > > I think crosvm moved from import model to export model a while ago.<br> > > It probably uses virgl_renderer_export_query now (didn't verify).<br> ><br> > You are right, crosvm does export fd and then "RegisterFdAtPciBarOffset".<br> ><br> > But, as far as I understand, this means that resources are allocated<br> > from host memory. In embedded systems, usually video memory is the<br> > same as RAM, but here RAM accessible to the guest and video memory<br> > provided by virglrenderer/crosvm will be separate. So I will have to<br> > limit separately, that for example, my guest should have 2 GB of RAM<br> > and 1 GB of video memory. Kindly please confirm that my understanding<br> > is correct.<br> <br> That is correct, but it has nothing to do with importing or exporting.<br> The difference is whether crosvm or virglrenderer allocates, but those<br> allocations are not from the guest memory no matter who allocates. I<br> think at least virglrenderer does not put any limit.<br> <br> For qemu 2D mode, there is indeed a property called max_hostmem to<br> limit total host allocation size.<br> _______________________________________________<br> virglrenderer-devel mailing list<br> virglrenderer-devel@lists.freedesktop.org<br> <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.freedesktop.org_mailman_listinfo_virglrenderer-2Ddevel&d=DwICAg&c=yzoHOc_ZK-sxl-kfGNSEvlJYanssXN3q-lhj0sp26wE&r=HXY0JlWsCRezqLYUvNUPwHZ5mqaW649zvjNgwUbCqdA&m=wzB6ubiaQAckPg2BQnh3xKd7rlrZb0vrg3WEO8LX3C0&s=K4dgo1ALtSeiMGoYSB30Hr2NMVK8pnsy0yPxudjWwtA&e=" target="_blank" rel="noopener noreferrer">https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.freedesktop.org_mailman_listinfo_virglrenderer-2Ddevel&d=DwICAg&c=yzoHOc_ZK-sxl-kfGNSEvlJYanssXN3q-lhj0sp26wE&r=HXY0JlWsCRezqLYUvNUPwHZ5mqaW649zvjNgwUbCqdA&m=wzB6ubiaQAckPg2BQnh3xKd7rlrZb0vrg3WEO8LX3C0&s=K4dgo1ALtSeiMGoYSB30Hr2NMVK8pnsy0yPxudjWwtA&e=</a> <br> </div> </span></font> <hr> This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. 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