From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52732) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHD9N-0007CI-Cr for qemu-devel@nongnu.org; Tue, 21 Nov 2017 13:20:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eHD9K-0003iw-25 for qemu-devel@nongnu.org; Tue, 21 Nov 2017 13:20:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32948) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eHD9J-0003iB-Ov for qemu-devel@nongnu.org; Tue, 21 Nov 2017 13:19:57 -0500 Message-ID: <1511288389.1080.14.camel@redhat.com> From: Rik van Riel Date: Tue, 21 Nov 2017 13:19:49 -0500 In-Reply-To: References: <1455443283.33337333.1500618150787.JavaMail.zimbra@redhat.com> <1888117852.34216619.1500992835767.JavaMail.zimbra@redhat.com> <1501016375.26846.21.camel@redhat.com> <1063764405.34607875.1501076841865.JavaMail.zimbra@redhat.com> <1501104453.26846.45.camel@redhat.com> <1501112787.4073.49.camel@redhat.com> <0a26793f-86f7-29e7-f61b-dc4c1ef08c8e@gmail.com> <378b10f3-b32f-84f5-2bbc-50c2ec5bcdd4@gmail.com> <86754966-281f-c3ed-938c-f009440de563@gmail.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-YkxgZx0ZzE65iqL9l6Ah" Mime-Version: 1.0 Subject: Re: [Qemu-devel] KVM "fake DAX" flushing interface - discussion List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong , Dan Williams Cc: Pankaj Gupta , Jan Kara , Stefan Hajnoczi , Stefan Hajnoczi , kvm-devel , Qemu Developers , "linux-nvdimm@lists.01.org" , ross zwisler , Paolo Bonzini , Kevin Wolf , Nitesh Narayan Lal , Haozhong Zhang , Ross Zwisler --=-YkxgZx0ZzE65iqL9l6Ah Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2017-11-03 at 14:21 +0800, Xiao Guangrong wrote: > On 11/03/2017 12:30 AM, Dan Williams wrote: > >=20 > > Good point, I was assuming that the mmio flush interface would be > > discovered separately from the NFIT-defined memory range. Perhaps > > via > > PCI in the guest? This piece of the proposal=C2=A0=C2=A0needs a bit mor= e > > thought... > >=20 >=20 > Consider the case that the vNVDIMM device on normal storage and > vNVDIMM device on real nvdimm hardware can both exist in VM, the > flush interface should be able to associate with the SPA region > respectively. That's why I'd like to integrate the flush interface > into NFIT/ACPI by using a separate table. Is it possible to be a > part of ACPI specification? :) It would also be perfectly fine to have the virtio PCI device indicate which vNVDIMM range it flushes. Since the guest OS needs to support that kind of device anyway, does it really matter which direction the device association points? We can go with the "best" interface for what could be a relatively slow flush (fsync on a file on ssd/disk on the host), which requires that the flushing task wait on completion asynchronously. If that kind of interface cannot be advertised through NFIT/ACPI, wouldn't it be perfectly fine to have only the virtio PCI device indicate which vNVDIMM range it flushes? --=20 All rights reversed --=-YkxgZx0ZzE65iqL9l6Ah Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJaFG5FAAoJEM553pKExN6DkB8H/2QuJPfLcfkc3wfyk1Y5B2We fipWPXwANS0sPCUl4JLIHG78qfV372SrmtnzTwbPpJsBts4IdkR7jcc0oXFIPrdz M7BxVEWuO1MSRnPNLtcDak8FoNwx5Ih987pZfrRaNT40N3XVwHsmdbEOnLiWw/gs bxPHlzhQ3x/vdbA6rwmxon/aIwa9/4D6wlmR1HQW8WE7Kwc5rrJxjTXb9/4znWVo yZsABziwJwK+9XhGXh2UmLp+7xf/PBR/X7uKvamPBL0sGS3pW8AS9sQxCi5CQ0IE DGEH7R1KTMDCJaY5+mVQf9Te351+4b1UMpIzkIueLjm5U+Kef7Omw5HjT0J/R2k= =Z+Y6 -----END PGP SIGNATURE----- --=-YkxgZx0ZzE65iqL9l6Ah--