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Commit 28158cd1 authored by Gavin Shan's avatar Gavin Shan Committed by Benjamin Herrenschmidt
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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: default avatarPriya M. A <priyama2@in.ibm.com>
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 9eccca08

arch/powerpc/kernel/eeh.c

+55 −0
Original line number Diff line number Diff line
@@ -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;