From 28158cd1b75180343efa7c4d7d2f8e74ccc63b8f Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Wed, 11 Feb 2015 10:20:49 +1100 Subject: [PATCH] powerpc/eeh: Enhance pcibios_set_pcie_reset_state() 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 Signed-off-by: Gavin Shan Signed-off-by: Benjamin Herrenschmidt --- 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 3b2252e7731b..19a897c810be 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c @@ -667,6 +667,55 @@ 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 @@ -689,13 +738,19 @@ 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;