[PATCH v3 2/2] PCI: Apply warm reset to specific devices

[Gavin Shan]

Currently, VFIO infrastructure depends on pci_reset_function()
to ensure the PCI device in clean state when passing to guest,
or being returned back to host. However, the function doesn't
work (or well) on some PCI devices on PowerPC platforms, which
potentially brings pending traffic over the boundary between
host/guest and usually causes memory corruption.

The patch applies warm reset to those PCI devices, which is
implemented based on pci_set_pcie_reset_state() to get clean
state when passing device from host to guest, or returning it
back to host. The reset request is routed to platform specific
pcibios_set_pcie_reset_state() and processed there.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
---
 drivers/pci/quirks.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 85f247e..9846d5e 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3504,6 +3504,22 @@ static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+static int pci_dev_warm_reset(struct pci_dev *pdev, int probe)
+{
+	int ret;
+
+	/* Check the device can take the reset or not */
+	if (probe)
+		return pci_set_pcie_reset_state(pdev, pcie_warm_reset, probe);
+
+	/* Issue warm reset */
+	ret = pci_set_pcie_reset_state(pdev, pcie_warm_reset, 0);
+	if (!ret)
+		ret = pci_set_pcie_reset_state(pdev, pcie_deassert_reset, 0);
+
+	return ret;
+}
+
 #define PCI_DEVICE_ID_INTEL_82599_SFP_VF   0x10ed
 #define PCI_DEVICE_ID_INTEL_IVB_M_VGA      0x0156
 #define PCI_DEVICE_ID_INTEL_IVB_M2_VGA     0x0166
@@ -3519,6 +3535,18 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
 		reset_intel_generic_dev },
 	{ PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
 		reset_chelsio_generic_dev },
+	{ PCI_VENDOR_ID_IBM, PCI_ANY_ID,
+		pci_dev_warm_reset },
+	{ PCI_VENDOR_ID_BROADCOM, PCI_DEVICE_ID_NX2_57800,
+		pci_dev_warm_reset },
+	{ PCI_VENDOR_ID_BROADCOM, PCI_DEVICE_ID_NX2_57840,
+		pci_dev_warm_reset },
+	{ PCI_VENDOR_ID_BROADCOM, PCI_DEVICE_ID_NX2_57810,
+		pci_dev_warm_reset },
+	{ PCI_VENDOR_ID_MELLANOX, PCI_ANY_ID,
+		pci_dev_warm_reset },
+	{ PCI_VENDOR_ID_TI, PCI_ANY_ID,
+		pci_dev_warm_reset },
 	{ 0 }
 };
 
-- 
1.8.3.2