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Tsirkin" To: Yao Xingtao Cc: marcel.apfelbaum@gmail.com, qemu-devel@nongnu.org, jonathan.cameron@huawei.com Subject: Re: [PATCH v2] pci-bridge: avoid linking a single downstream port more than once Message-ID: <20240717080308-mutt-send-email-mst@kernel.org> References: <20240717085621.55315-1-yaoxt.fnst@fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240717085621.55315-1-yaoxt.fnst@fujitsu.com> Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, T_SPF_TEMPERROR=0.01 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jul 17, 2024 at 04:56:21AM -0400, Yao Xingtao wrote: > Since the downstream port is not checked, two slots can be linked to > a single port. However, this can prevent the driver from detecting the > device properly. > > It is necessary to ensure that a downstream port is not linked more than > once. > > Links: https://lore.kernel.org/qemu-devel/OSZPR01MB6453BC61D2FF4035F18084EF8DDC2@OSZPR01MB6453.jpnprd01.prod.outlook.com > Signed-off-by: Yao Xingtao You also need to take ARI into account. That can look like slot != 0. > --- > V1[1] -> V2: > - Move downstream port check forward > > [1] https://lore.kernel.org/qemu-devel/20240704033834.3362-1-yaoxt.fnst@fujitsu.com > --- > hw/pci-bridge/cxl_downstream.c | 5 +++++ > hw/pci-bridge/pcie_root_port.c | 5 +++++ > hw/pci-bridge/xio3130_downstream.c | 5 +++++ > 3 files changed, 15 insertions(+) > > diff --git a/hw/pci-bridge/cxl_downstream.c b/hw/pci-bridge/cxl_downstream.c > index 742da07a015a..af81ddfeec13 100644 > --- a/hw/pci-bridge/cxl_downstream.c > +++ b/hw/pci-bridge/cxl_downstream.c > @@ -142,6 +142,11 @@ static void cxl_dsp_realize(PCIDevice *d, Error **errp) > MemoryRegion *component_bar = &cregs->component_registers; > int rc; > > + if (pcie_find_port_by_pn(pci_get_bus(d), p->port) != NULL) { > + error_setg(errp, "Can't link port, error %d", -EBUSY); > + return; > + } > + > pci_bridge_initfn(d, TYPE_PCIE_BUS); > pcie_port_init_reg(d); > > diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c > index 09a34786bc62..a540204bda27 100644 > --- a/hw/pci-bridge/pcie_root_port.c > +++ b/hw/pci-bridge/pcie_root_port.c > @@ -67,6 +67,11 @@ static void rp_realize(PCIDevice *d, Error **errp) > PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(d); > int rc; > > + if (pcie_find_port_by_pn(pci_get_bus(d), p->port) != NULL) { > + error_setg(errp, "Can't link port, error %d", -EBUSY); > + return; > + } > + > pci_config_set_interrupt_pin(d->config, 1); > if (d->cap_present & QEMU_PCIE_CAP_CXL) { > pci_bridge_initfn(d, TYPE_CXL_BUS); > diff --git a/hw/pci-bridge/xio3130_downstream.c b/hw/pci-bridge/xio3130_downstream.c > index 907d5105b019..63f6baa615fd 100644 > --- a/hw/pci-bridge/xio3130_downstream.c > +++ b/hw/pci-bridge/xio3130_downstream.c > @@ -69,6 +69,11 @@ static void xio3130_downstream_realize(PCIDevice *d, Error **errp) > PCIESlot *s = PCIE_SLOT(d); > int rc; > > + if (pcie_find_port_by_pn(pci_get_bus(d), p->port) != NULL) { > + error_setg(errp, "Can't link port, error %d", -EBUSY); > + return; > + } > + > pci_bridge_initfn(d, TYPE_PCIE_BUS); > pcie_port_init_reg(d); > > -- > 2.37.3