Function pcibios_set_pcie_reset_state() is possibly called by
pci_reset_function(), on which VFIO infrastructure depends to
issue reset. pcibios_set_pcie_reset_state() is issuing reset
on the parent PE of the indicated PCI device. The reset causes
state lost on all PCI devices except the indicated one as the
argument to pcibios_set_pcie_reset_state(). Also, sideband
MMIO access from guest when issuing reset would cause unexpected
EEH error.
For above two issues, the patch applies following enhancements
to pcibios_set_pcie_reset_state():
* For all PCI devices except the indicated one, save their
state prior to reset and restore state after that.
* Explicitly freeze PE prior to reset and unfreeze it after
that, in order to avoid unexpected EEH error.
Tested-by: Priya M. A <priya...@in.ibm.com>
Signed-off-by: Gavin Shan <gws...@linux.vnet.ibm.com>
---
arch/powerpc/kernel/eeh.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index e1b6d8e..9c67538 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -660,6 +660,55 @@ int eeh_pci_enable(struct eeh_pe *pe, int function)
return rc;
}
+static void *eeh_disable_and_save_dev_state(void *data, void *userdata)
+{
+ struct eeh_dev *edev = data;
+ struct pci_dev *pdev = eeh_dev_to_pci_dev(edev);
+ struct pci_dev *dev = userdata;
+
+ /*
+ * The caller should have disabled and saved the
+ * state for the specified device
+ */
+ if (!pdev || pdev == dev)
+ return NULL;
+
+ /* Ensure we have D0 power state */
+ pci_set_power_state(pdev, PCI_D0);
+
+ /* Save device state */
+ pci_save_state(pdev);
+
+ /*
+ * Disable device to avoid any DMA traffic and
+ * interrupt from the device
+ */
+ pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);
+
+ return NULL;
+}
+
+static void *eeh_restore_dev_state(void *data, void *userdata)
+{
+ struct eeh_dev *edev = data;
+ struct device_node *dn = eeh_dev_to_of_node(edev);
+ struct pci_dev *pdev = eeh_dev_to_pci_dev(edev);
+ struct pci_dev *dev = userdata;
+
+ if (!pdev)
+ return NULL;
+
+ /* Apply customization from firmware */
+ if (dn && eeh_ops->restore_config)
+ eeh_ops->restore_config(dn);
+
+ /* The caller should restore state for the specified device */
+ if (pdev != dev)
+ pci_save_state(pdev);
+
+ return NULL;
+}
+
/**
* pcibios_set_pcie_slot_reset - Set PCI-E reset state
* @dev: pci device struct
@@ -682,13 +731,19 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev,
enum pcie_reset_state stat
switch (state) {
case pcie_deassert_reset:
eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);
+ eeh_unfreeze_pe(pe, false);
eeh_pe_state_clear(pe, EEH_PE_CFG_BLOCKED);
+ eeh_pe_dev_traverse(pe, eeh_restore_dev_state, dev);
break;
case pcie_hot_reset:
+ eeh_ops->set_option(pe, EEH_OPT_FREEZE_PE);
+ eeh_pe_dev_traverse(pe, eeh_disable_and_save_dev_state, dev);
eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
eeh_ops->reset(pe, EEH_RESET_HOT);
break;
case pcie_warm_reset:
+ eeh_ops->set_option(pe, EEH_OPT_FREEZE_PE);
+ eeh_pe_dev_traverse(pe, eeh_disable_and_save_dev_state, dev);
eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
break;
--
1.8.3.2
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