[PATCH RFC 24/25] PCI: pci-lu-pf-stub: Add a PF stub driver for Live Update testing

[Chris Li <chrisl@kernel.org>]

The pci-lu-stub driver will always request device in probe(). However if
the PF driver might be add the liveupdate device list due to "depended" bit
rather than "requested" bit.

Create the pci-lu-stub-pf driver base on the pci-lu-stuf driver, it will
not request the device at probe().

For PF device, also restore the number of VFs at probe().

Signed-off-by: Chris Li <chrisl@kernel.org>
---
 drivers/pci/pci-lu-stub.c | 85 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 81 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci-lu-stub.c b/drivers/pci/pci-lu-stub.c
index ea8142dcb250d31cbf817df957157bc4ec3a876d..ff6230102b83ff3ad646c23b79d4e1b6de58b43f 100644
--- a/drivers/pci/pci-lu-stub.c
+++ b/drivers/pci/pci-lu-stub.c
@@ -5,6 +5,8 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 
+#include "pci.h"
+
 struct pci_lu_stub_ser {
 	u16 dev_id;
 } __packed;
@@ -32,15 +34,47 @@ static int validate_folio(struct pci_dev *dev, struct folio *folio)
 	return 0;
 }
 
-static int pci_lu_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
+static bool is_pf_driver(struct pci_dev *dev)
+{
+	return pci_get_drvdata(dev);
+}
+
+static int check_lu_flags(struct pci_dev *dev, bool is_pf)
+{
+	struct dev_liveupdate *lu = &dev->dev.lu;
+	bool expect_requested = !is_pf;
+	bool expect_depended = is_pf;
+
+	if (lu->requested != expect_requested) {
+		pci_err(dev, "Device requested bit %d not match expected %d\n",
+			lu->requested, expect_requested);
+		return -EINVAL;
+	}
+
+	if (lu->depended != expect_depended) {
+		pci_err(dev, "Device requested bit %d not match expected %d\n",
+			lu->depended, expect_depended);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int __pci_lu_stub_probe(struct pci_dev *dev, const struct pci_device_id *id,
+			       bool is_pf)
 {
 	struct folio *folio;
 	u64 data;
 	int ret;
+	int vfs;
+	struct dev_liveupdate *lu = &dev->dev.lu;
+	struct pci_dev_ser *s;
 
+	pci_set_drvdata(dev, (void *)(intptr_t) is_pf);
 	if (liveupdate_state_normal()) {
-		pci_info(dev, "Marking device as liveupdate requested\n");
-		dev->dev.lu.requested = 1;
+		if (!is_pf) {
+			pci_info(dev, "Marking device as liveupdate requested\n");
+			lu->requested = 1;
+		}
 		return 0;
 	}
 
@@ -49,6 +83,10 @@ static int pci_lu_stub_probe(struct pci_dev *dev, const struct pci_device_id *id
 		return -EOPNOTSUPP;
 	}
 
+	ret = check_lu_flags(dev, is_pf);
+	if (ret)
+		return ret;
+
 	ret = pci_liveupdate_get_driver_data(dev, &data);
 	if (ret) {
 		pci_err(dev, "Failed to get driver data for device (%d)\n", ret);
@@ -63,7 +101,31 @@ static int pci_lu_stub_probe(struct pci_dev *dev, const struct pci_device_id *id
 		return -ENOENT;
 	}
 
-	return validate_folio(dev, folio);
+	ret = validate_folio(dev, folio);
+	if (ret)
+		return ret;
+
+	s = lu->dev_state;
+	vfs = s->num_vfs;
+	if (dev->is_physfn && vfs) {
+		ret = pci_sriov_configure_simple(dev, vfs);
+		if (vfs != ret) {
+			pci_err(dev, "Failed to restore num VFs %d got %d\n",
+				vfs, ret);
+			return (ret < 0) ? ret : -EAGAIN;
+		}
+	}
+	return  0;
+}
+
+static int pci_lu_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	return __pci_lu_stub_probe(dev, id, false);
+}
+
+static int pci_lu_stub_pf_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	return __pci_lu_stub_probe(dev, id, true);
 }
 
 static void pci_lu_stub_remove(struct pci_dev *dev)
@@ -74,10 +136,15 @@ static void pci_lu_stub_remove(struct pci_dev *dev)
 
 static int pci_lu_stub_prepare(struct device *dev, u64 *data)
 {
+	struct pci_dev *pdev = to_pci_dev(dev);
 	struct pci_lu_stub_ser *ser;
 	struct folio *folio;
 	int ret;
 
+	ret = check_lu_flags(pdev, is_pf_driver(pdev));
+	if (ret)
+		return ret;
+
 	folio = folio_alloc(GFP_KERNEL | __GFP_ZERO, get_order(sizeof(*ser)));
 	if (!folio)
 		return -ENOMEM;
@@ -135,5 +202,15 @@ static struct pci_driver pci_lu_stub_driver = {
 	.driver.lu	= &liveupdate_ops,
 };
 
+static struct pci_driver pci_lu_stub_pf_driver = {
+	.name		= "pci-lu-stub-pf",
+	.id_table	= pci_lu_stub_id_table,
+	.probe		= pci_lu_stub_pf_probe,
+	.remove		= pci_lu_stub_remove,
+	.sriov_configure = pci_sriov_configure_simple,
+	.driver.lu	= &liveupdate_ops,
+};
+
 module_pci_driver(pci_lu_stub_driver);
+module_pci_driver(pci_lu_stub_pf_driver);
 MODULE_LICENSE("GPL");

-- 
2.50.1.487.gc89ff58d15-goog