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Tue, 29 Sep 2020 08:56:13 +0000 (UTC) Received: from laptop.redhat.com (ovpn-113-210.ams2.redhat.com [10.36.113.210]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5956055773; Tue, 29 Sep 2020 08:56:10 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, stefanha@redhat.com, fam@euphon.net, philmd@redhat.com, alex.williamson@redhat.com Subject: [PATCH v2 2/2] util/vfio-helpers: Rework the IOVA allocator to avoid IOVA reserved regions Date: Tue, 29 Sep 2020 10:55:50 +0200 Message-Id: <20200929085550.30926-3-eric.auger@redhat.com> In-Reply-To: <20200929085550.30926-1-eric.auger@redhat.com> References: <20200929085550.30926-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eric.auger@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/29 02:22:44 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.687, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: lvivier@redhat.com, kwolf@redhat.com, cohuck@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Introduce the qemu_vfio_find_fixed/temp_iova helpers which respectively allocate IOVAs from the bottom/top parts of the usable IOVA range, without picking within host IOVA reserved windows. The allocation remains basic: if the size is too big for the remaining of the current usable IOVA range, we jump to the next one, leaving a hole in the address map. Signed-off-by: Eric Auger --- v1 -> v2: - handle possible wrap --- util/vfio-helpers.c | 57 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 53 insertions(+), 4 deletions(-) diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c index ba0ee6e21c..71145970f3 100644 --- a/util/vfio-helpers.c +++ b/util/vfio-helpers.c @@ -667,6 +667,50 @@ static bool qemu_vfio_verify_mappings(QEMUVFIOState *s) return true; } +static int +qemu_vfio_find_fixed_iova(QEMUVFIOState *s, size_t size, uint64_t *iova) +{ + int i; + + for (i = 0; i < s->nb_iova_ranges; i++) { + if (s->usable_iova_ranges[i].end < s->low_water_mark) { + continue; + } + s->low_water_mark = + MAX(s->low_water_mark, s->usable_iova_ranges[i].start); + + if (s->usable_iova_ranges[i].end - s->low_water_mark + 1 >= size || + s->usable_iova_ranges[i].end - s->low_water_mark + 1 == 0) { + *iova = s->low_water_mark; + s->low_water_mark += size; + return 0; + } + } + return -ENOMEM; +} + +static int +qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size, uint64_t *iova) +{ + int i; + + for (i = s->nb_iova_ranges - 1; i >= 0; i--) { + if (s->usable_iova_ranges[i].start > s->high_water_mark) { + continue; + } + s->high_water_mark = + MIN(s->high_water_mark, s->usable_iova_ranges[i].end + 1); + + if (s->high_water_mark - s->usable_iova_ranges[i].start + 1 >= size || + s->high_water_mark - s->usable_iova_ranges[i].start + 1 == 0) { + *iova = s->high_water_mark - size; + s->high_water_mark = *iova; + return 0; + } + } + return -ENOMEM; +} + /* Map [host, host + size) area into a contiguous IOVA address space, and store * the result in @iova if not NULL. The caller need to make sure the area is * aligned to page size, and mustn't overlap with existing mapping areas (split @@ -693,7 +737,11 @@ int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size, goto out; } if (!temporary) { - iova0 = s->low_water_mark; + if (qemu_vfio_find_fixed_iova(s, size, &iova0)) { + ret = -ENOMEM; + goto out; + } + mapping = qemu_vfio_add_mapping(s, host, size, index + 1, iova0); if (!mapping) { ret = -ENOMEM; @@ -705,15 +753,16 @@ int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size, qemu_vfio_undo_mapping(s, mapping, NULL); goto out; } - s->low_water_mark += size; qemu_vfio_dump_mappings(s); } else { - iova0 = s->high_water_mark - size; + if (qemu_vfio_find_temp_iova(s, size, &iova0)) { + ret = -ENOMEM; + goto out; + } ret = qemu_vfio_do_mapping(s, host, size, iova0); if (ret) { goto out; } - s->high_water_mark -= size; } } if (iova) {