From be20bbcb0a8cb5597cc62b3e28d275919f3431df Mon Sep 17 00:00:00 2001 From: Kazufumi Ikeda Date: Mon, 25 Mar 2019 20:43:19 +0100 Subject: [PATCH 1/4] PCI: rcar: Add the initialization of PCIe link in resume_noirq() Reestablish the PCIe link very early in the resume process in case it went down to prevent PCI accesses from hanging the bus. Such accesses can happen early in the PCI resume process, as early as the SUSPEND_RESUME_NOIRQ step, thus the link must be reestablished in the driver resume_noirq() callback. Fixes: e015f88c368d ("PCI: rcar: Add support for R-Car H3 to pcie-rcar") Signed-off-by: Kazufumi Ikeda Signed-off-by: Gaku Inami Signed-off-by: Marek Vasut [lorenzo.pieralisi@arm.com: reformatted commit log] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Simon Horman Reviewed-by: Geert Uytterhoeven Acked-by: Wolfram Sang Cc: stable@vger.kernel.org Cc: Geert Uytterhoeven Cc: Phil Edworthy Cc: Simon Horman Cc: Wolfram Sang Cc: linux-renesas-soc@vger.kernel.org --- drivers/pci/controller/pcie-rcar.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c index c8febb009454..6a4e435bd35f 100644 --- a/drivers/pci/controller/pcie-rcar.c +++ b/drivers/pci/controller/pcie-rcar.c @@ -46,6 +46,7 @@ /* Transfer control */ #define PCIETCTLR 0x02000 +#define DL_DOWN BIT(3) #define CFINIT 1 #define PCIETSTR 0x02004 #define DATA_LINK_ACTIVE 1 @@ -94,6 +95,7 @@ #define MACCTLR 0x011058 #define SPEED_CHANGE BIT(24) #define SCRAMBLE_DISABLE BIT(27) +#define PMSR 0x01105c #define MACS2R 0x011078 #define MACCGSPSETR 0x011084 #define SPCNGRSN BIT(31) @@ -1130,6 +1132,7 @@ static int rcar_pcie_probe(struct platform_device *pdev) pcie = pci_host_bridge_priv(bridge); pcie->dev = dev; + platform_set_drvdata(pdev, pcie); err = pci_parse_request_of_pci_ranges(dev, &pcie->resources, NULL); if (err) @@ -1221,10 +1224,28 @@ err_free_bridge: return err; } +static int rcar_pcie_resume_noirq(struct device *dev) +{ + struct rcar_pcie *pcie = dev_get_drvdata(dev); + + if (rcar_pci_read_reg(pcie, PMSR) && + !(rcar_pci_read_reg(pcie, PCIETCTLR) & DL_DOWN)) + return 0; + + /* Re-establish the PCIe link */ + rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR); + return rcar_pcie_wait_for_dl(pcie); +} + +static const struct dev_pm_ops rcar_pcie_pm_ops = { + .resume_noirq = rcar_pcie_resume_noirq, +}; + static struct platform_driver rcar_pcie_driver = { .driver = { .name = "rcar-pcie", .of_match_table = rcar_pcie_of_match, + .pm = &rcar_pcie_pm_ops, .suppress_bind_attrs = true, }, .probe = rcar_pcie_probe, From 05f151a73ec2b23ffbff706e5203e729a995cdc2 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Mon, 4 Mar 2019 21:34:48 +0000 Subject: [PATCH 2/4] PCI: hv: Fix a memory leak in hv_eject_device_work() When a device is created in new_pcichild_device(), hpdev->refs is set to 2 (i.e. the initial value of 1 plus the get_pcichild()). When we hot remove the device from the host, in a Linux VM we first call hv_pci_eject_device(), which increases hpdev->refs by get_pcichild() and then schedules a work of hv_eject_device_work(), so hpdev->refs becomes 3 (let's ignore the paired get/put_pcichild() in other places). But in hv_eject_device_work(), currently we only call put_pcichild() twice, meaning the 'hpdev' struct can't be freed in put_pcichild(). Add one put_pcichild() to fix the memory leak. The device can also be removed when we run "rmmod pci-hyperv". On this path (hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_devices_present()), hpdev->refs is 2, and we do correctly call put_pcichild() twice in pci_devices_present_work(). Fixes: 4daace0d8ce8 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Signed-off-by: Dexuan Cui [lorenzo.pieralisi@arm.com: commit log rework] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Stephen Hemminger Reviewed-by: Michael Kelley Cc: stable@vger.kernel.org --- drivers/pci/controller/pci-hyperv.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 95441a35eceb..30f16b882746 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1900,6 +1900,9 @@ static void hv_eject_device_work(struct work_struct *work) sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0); + /* For the get_pcichild() in hv_pci_eject_device() */ + put_pcichild(hpdev); + /* For the two refs got in new_pcichild_device() */ put_pcichild(hpdev); put_pcichild(hpdev); put_hvpcibus(hpdev->hbus); From 15becc2b56c6eda3d9bf5ae993bafd5661c1fad1 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Mon, 4 Mar 2019 21:34:48 +0000 Subject: [PATCH 3/4] PCI: hv: Add hv_pci_remove_slots() when we unload the driver When we unload the pci-hyperv host controller driver, the host does not send us a PCI_EJECT message. In this case we also need to make sure the sysfs PCI slot directory is removed, otherwise a command on a slot file eg: "cat /sys/bus/pci/slots/2/address" will trigger a "BUG: unable to handle kernel paging request" and, if we unload/reload the driver several times we would end up with stale slot entries in PCI slot directories in /sys/bus/pci/slots/ root@localhost:~# ls -rtl /sys/bus/pci/slots/ total 0 drwxr-xr-x 2 root root 0 Feb 7 10:49 2 drwxr-xr-x 2 root root 0 Feb 7 10:49 2-1 drwxr-xr-x 2 root root 0 Feb 7 10:51 2-2 Add the missing code to remove the PCI slot and fix the current behaviour. Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot information") Signed-off-by: Dexuan Cui [lorenzo.pieralisi@arm.com: reformatted the log] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Stephen Hemminger Reviewed-by: Michael Kelley Cc: stable@vger.kernel.org --- drivers/pci/controller/pci-hyperv.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 30f16b882746..b489412e3502 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1486,6 +1486,21 @@ static void hv_pci_assign_slots(struct hv_pcibus_device *hbus) } } +/* + * Remove entries in sysfs pci slot directory. + */ +static void hv_pci_remove_slots(struct hv_pcibus_device *hbus) +{ + struct hv_pci_dev *hpdev; + + list_for_each_entry(hpdev, &hbus->children, list_entry) { + if (!hpdev->pci_slot) + continue; + pci_destroy_slot(hpdev->pci_slot); + hpdev->pci_slot = NULL; + } +} + /** * create_root_hv_pci_bus() - Expose a new root PCI bus * @hbus: Root PCI bus, as understood by this driver @@ -2680,6 +2695,7 @@ static int hv_pci_remove(struct hv_device *hdev) pci_lock_rescan_remove(); pci_stop_root_bus(hbus->pci_bus); pci_remove_root_bus(hbus->pci_bus); + hv_pci_remove_slots(hbus); pci_unlock_rescan_remove(); hbus->state = hv_pcibus_removed; } From 340d455699400f2c2c0f9b3f703ade3085cdb501 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Mon, 4 Mar 2019 21:34:49 +0000 Subject: [PATCH 4/4] PCI: hv: Add pci_destroy_slot() in pci_devices_present_work(), if necessary When we hot-remove a device, usually the host sends us a PCI_EJECT message, and a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. When we execute the quick hot-add/hot-remove test, the host may not send us the PCI_EJECT message if the guest has not fully finished the initialization by sending the PCI_RESOURCES_ASSIGNED* message to the host, so it's potentially unsafe to only depend on the pci_destroy_slot() in hv_eject_device_work() because the code path create_root_hv_pci_bus() -> hv_pci_assign_slots() is not called in this case. Note: in this case, the host still sends the guest a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. In the quick hot-add/hot-remove test, we can have such a race before the code path pci_devices_present_work() -> new_pcichild_device() adds the new device into the hbus->children list, we may have already received the PCI_EJECT message, and since the tasklet handler hv_pci_onchannelcallback() may fail to find the "hpdev" by calling get_pcichild_wslot(hbus, dev_message->wslot.slot) hv_pci_eject_device() is not called; Later, by continuing execution create_root_hv_pci_bus() -> hv_pci_assign_slots() creates the slot and the PCI_BUS_RELATIONS message with bus_rel->device_count == 0 removes the device from hbus->children, and we end up being unable to remove the slot in hv_pci_remove() -> hv_pci_remove_slots() Remove the slot in pci_devices_present_work() when the device is removed to address this race. pci_devices_present_work() and hv_eject_device_work() run in the singled-threaded hbus->wq, so there is not a double-remove issue for the slot. We cannot offload hv_pci_eject_device() from hv_pci_onchannelcallback() to the workqueue, because we need the hv_pci_onchannelcallback() synchronously call hv_pci_eject_device() to poll the channel ringbuffer to work around the "hangs in hv_compose_msi_msg()" issue fixed in commit de0aa7b2f97d ("PCI: hv: Fix 2 hang issues in hv_compose_msi_msg()") Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot information") Signed-off-by: Dexuan Cui [lorenzo.pieralisi@arm.com: rewritten commit log] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Stephen Hemminger Reviewed-by: Michael Kelley Cc: stable@vger.kernel.org --- drivers/pci/controller/pci-hyperv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index b489412e3502..82acd6155adf 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -1776,6 +1776,10 @@ static void pci_devices_present_work(struct work_struct *work) hpdev = list_first_entry(&removed, struct hv_pci_dev, list_entry); list_del(&hpdev->list_entry); + + if (hpdev->pci_slot) + pci_destroy_slot(hpdev->pci_slot); + put_pcichild(hpdev); }