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Fri, 28 Feb 2020 13:01:54 -0800 (PST) Date: Fri, 28 Feb 2020 16:01:52 -0500 From: Peter Xu To: David Hildenbrand Subject: Re: [PATCH v3 12/15] util: vfio-helpers: Implement ram_block_resized() Message-ID: <20200228210152.GD180973@xz-x1> References: <20200228194257.GV180973@xz-x1> <509A885B-055F-4EEF-96FA-2EDA759F4F2C@redhat.com> MIME-Version: 1.0 In-Reply-To: <509A885B-055F-4EEF-96FA-2EDA759F4F2C@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S . Tsirkin" , Igor Kotrasinski , Stefan Hajnoczi , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" , Alex Williamson , Murilo Opsfelder Araujo , Igor Mammedov , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Feb 28, 2020 at 09:16:28PM +0100, David Hildenbrand wrote: >=20 [...] > >> @@ -631,7 +658,7 @@ int qemu_vfio_dma_map(QEMUVFIOState *s, void *host= , size_t size, > >> qemu_vfio_remove_mapping(s, mapping); > >> goto out; > >> } > >> - s->low_water_mark +=3D size; > >> + s->low_water_mark +=3D max_size; > >=20 > > I think it's fine to only increase the low water mark here, however > > imo it would be better to also cache the max size in IOVAMapping too, > > then in resize() we double check new_size <=3D max_size? It also makes > > IOVAMapping more self contained. > >=20 >=20 > I=E2=80=98ll have a look how much additional code that will imply - if it= =E2=80=98s simple, I=E2=80=98ll do it. AFAICT it'll be as simple as introducing IOVAMapping.max_size, then pass max_size into qemu_vfio_add_mapping(). Thanks, --=20 Peter Xu