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Date: Tue, 19 Nov 2019 23:16:56 -0800
From: Dexuan Cui <decui@...rosoft.com>
To: kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
sashal@...nel.org, lorenzo.pieralisi@....com, bhelgaas@...gle.com,
linux-hyperv@...r.kernel.org, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, mikelley@...rosoft.com,
Alexander.Levin@...rosoft.com
Cc: Dexuan Cui <decui@...rosoft.com>
Subject: [PATCH v2 2/4] PCI: hv: Add the support of hibernation
Implement the suspend/resume callbacks.
We must make sure there is no pending work items before we call
vmbus_close().
Signed-off-by: Dexuan Cui <decui@...rosoft.com>
---
Changes in v2: this patch is a simple merge of 2 previous smaller patches,
accordign to the suggestion of Lorenzo Pieralisi <lorenzo.pieralisi@....com>.
drivers/pci/controller/pci-hyperv.c | 107 +++++++++++++++++++++++++++-
1 file changed, 105 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 65f18f840ce9..e71eb6e0bfdd 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -455,6 +455,7 @@ enum hv_pcibus_state {
hv_pcibus_init = 0,
hv_pcibus_probed,
hv_pcibus_installed,
+ hv_pcibus_removing,
hv_pcibus_removed,
hv_pcibus_maximum
};
@@ -1681,6 +1682,23 @@ static void prepopulate_bars(struct hv_pcibus_device *hbus)
spin_lock_irqsave(&hbus->device_list_lock, flags);
+ /*
+ * Clear the memory enable bit, in case it's already set. This occurs
+ * in the suspend path of hibernation, where the device is suspended,
+ * resumed and suspended again: see hibernation_snapshot() and
+ * hibernation_platform_enter().
+ *
+ * If the memory enable bit is already set, Hyper-V sliently ignores
+ * the below BAR updates, and the related PCI device driver can not
+ * work, because reading from the device register(s) always returns
+ * 0xFFFFFFFF.
+ */
+ list_for_each_entry(hpdev, &hbus->children, list_entry) {
+ _hv_pcifront_read_config(hpdev, PCI_COMMAND, 2, &command);
+ command &= ~PCI_COMMAND_MEMORY;
+ _hv_pcifront_write_config(hpdev, PCI_COMMAND, 2, command);
+ }
+
/* Pick addresses for the BARs. */
do {
list_for_each_entry(hpdev, &hbus->children, list_entry) {
@@ -2107,6 +2125,12 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
unsigned long flags;
bool pending_dr;
+ if (hbus->state == hv_pcibus_removing) {
+ dev_info(&hbus->hdev->device,
+ "PCI VMBus BUS_RELATIONS: ignored\n");
+ return;
+ }
+
dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
if (!dr_wrk)
return;
@@ -2223,11 +2247,19 @@ static void hv_eject_device_work(struct work_struct *work)
*/
static void hv_pci_eject_device(struct hv_pci_dev *hpdev)
{
+ struct hv_pcibus_device *hbus = hpdev->hbus;
+ struct hv_device *hdev = hbus->hdev;
+
+ if (hbus->state == hv_pcibus_removing) {
+ dev_info(&hdev->device, "PCI VMBus EJECT: ignored\n");
+ return;
+ }
+
hpdev->state = hv_pcichild_ejecting;
get_pcichild(hpdev);
INIT_WORK(&hpdev->wrk, hv_eject_device_work);
- get_hvpcibus(hpdev->hbus);
- queue_work(hpdev->hbus->wq, &hpdev->wrk);
+ get_hvpcibus(hbus);
+ queue_work(hbus->wq, &hpdev->wrk);
}
/**
@@ -3107,6 +3139,75 @@ static int hv_pci_remove(struct hv_device *hdev)
return ret;
}
+static int hv_pci_suspend(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ enum hv_pcibus_state old_state;
+ int ret;
+
+ tasklet_disable(&hdev->channel->callback_event);
+
+ /* Change the hbus state to prevent new work items. */
+ old_state = hbus->state;
+ if (hbus->state == hv_pcibus_installed)
+ hbus->state = hv_pcibus_removing;
+
+ tasklet_enable(&hdev->channel->callback_event);
+
+ if (old_state != hv_pcibus_installed)
+ return -EINVAL;
+
+ flush_workqueue(hbus->wq);
+
+ ret = hv_pci_bus_exit(hdev, true);
+ if (ret)
+ return ret;
+
+ vmbus_close(hdev->channel);
+
+ return 0;
+}
+
+static int hv_pci_resume(struct hv_device *hdev)
+{
+ struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+ enum pci_protocol_version_t version[1];
+ int ret;
+
+ hbus->state = hv_pcibus_init;
+
+ ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
+ hv_pci_onchannelcallback, hbus);
+ if (ret)
+ return ret;
+
+ /* Only use the version that was in use before hibernation. */
+ version[0] = pci_protocol_version;
+ ret = hv_pci_protocol_negotiation(hdev, version, 1);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_query_relations(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_pci_enter_d0(hdev);
+ if (ret)
+ goto out;
+
+ ret = hv_send_resources_allocated(hdev);
+ if (ret)
+ goto out;
+
+ prepopulate_bars(hbus);
+
+ hbus->state = hv_pcibus_installed;
+ return 0;
+out:
+ vmbus_close(hdev->channel);
+ return ret;
+}
+
static const struct hv_vmbus_device_id hv_pci_id_table[] = {
/* PCI Pass-through Class ID */
/* 44C4F61D-4444-4400-9D52-802E27EDE19F */
@@ -3121,6 +3222,8 @@ static struct hv_driver hv_pci_drv = {
.id_table = hv_pci_id_table,
.probe = hv_pci_probe,
.remove = hv_pci_remove,
+ .suspend = hv_pci_suspend,
+ .resume = hv_pci_resume,
};
static void __exit exit_hv_pci_drv(void)
--
2.19.1
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