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Fri, 10 Feb 2023 16:59:19 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.76]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0183A2166B29; Fri, 10 Feb 2023 16:59:17 +0000 (UTC) Date: Fri, 10 Feb 2023 16:59:15 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Nikolay Borisov Cc: dgilbert@redhat.com, qemu-devel@nongnu.org, jfehlig@suse.com, Claudio.Fontana@suse.com, dfaggioli@suse.com Subject: Re: [PATCH v3 09/14] migration: add qemu_get_buffer_at Message-ID: References: <20221028103914.908728-1-nborisov@suse.com> <20221028103914.908728-10-nborisov@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221028103914.908728-10-nborisov@suse.com> User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Oct 28, 2022 at 01:39:09PM +0300, Nikolay Borisov wrote: > Restoring a 'fixed-ram' enabled migration stream would require reading > from specific offsets in the file so add a helper to QEMUFile that uses > the newly introduced qio_channel_file_preadv. > > Signed-off-by: Nikolay Borisov > --- > migration/qemu-file.c | 23 +++++++++++++++++++++++ > migration/qemu-file.h | 1 + > 2 files changed, 24 insertions(+) > > diff --git a/migration/qemu-file.c b/migration/qemu-file.c > index d0e0ba6150f7..b24972d5728d 100644 > --- a/migration/qemu-file.c > +++ b/migration/qemu-file.c > @@ -564,6 +564,29 @@ void qemu_put_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen, off_t po > return; > } > > + > +size_t qemu_get_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen, off_t pos) > +{ > + Error *err = NULL; > + struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen }; > + ssize_t ret; > + > + if (f->last_error) { > + return 0; > + } > + > + ret = qio_channel_io_preadv(f->ioc, &iov, 1, pos, &err); If we have a qio_channel_io_preadv that does NOT use iovecs, then this code gets simpler, as the iovec wrapping can be hidden in the QIOChannel code. > + if (ret == -1) { > + goto error; > + } > + > + return (size_t)ret; > + > + error: > + qemu_file_set_error_obj(f, -EIO, err); > + return 0; > +} > + > void qemu_set_offset(QEMUFile *f, off_t off, int whence) > { > Error *err = NULL; > diff --git a/migration/qemu-file.h b/migration/qemu-file.h > index 33cfc07b81d1..ab10c3ad7e42 100644 > --- a/migration/qemu-file.h > +++ b/migration/qemu-file.h > @@ -151,6 +151,7 @@ void qemu_file_set_blocking(QEMUFile *f, bool block); > void qemu_set_offset(QEMUFile *f, off_t off, int whence); > off_t qemu_get_offset(QEMUFile *f); > void qemu_put_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen, off_t pos); > +size_t qemu_get_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen, off_t pos); > > void ram_control_before_iterate(QEMUFile *f, uint64_t flags); > void ram_control_after_iterate(QEMUFile *f, uint64_t flags); > -- > 2.34.1 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|