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powerpc/eeh: Enhance pcibios_set_pcie_reset_state()

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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 <priyama2@in.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Gavin Shan 2015-02-11 10:20:49 +11:00 • committed by Benjamin Herrenschmidt
commit 28158cd1b7
1 changed files with 55 additions and 0 deletions
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55
arch/powerpc/kernel/eeh.c
View file

@ -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;