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Commit 4eeeff0e authored by Gavin Shan's avatar Gavin Shan Committed by Michael Ellerman
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powerpc/eeh: Unfreeze PE on enabling EEH functionality 



When passing through PE to guest, that's possibly in frozen
state. The driver for the pass-through devices on guest side
can't be loaded successfully as reported. We already had one
gate in eeh_dev_open() to clear PE frozen state accordingly,
but that's not enough because the function is only called at
QEMU startup for once.

The patch adds another gate in eeh_pe_set_option() so that the
PE frozen state can be cleared at QEMU restart time.

Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 4d4f577e

arch/powerpc/include/asm/eeh.h

+1 −0
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ void eeh_add_device_late(struct pci_dev *); 
void eeh_add_device_tree_late(struct pci_bus *);

void eeh_add_sysfs_files(struct pci_bus *);

void eeh_remove_device(struct pci_dev *);

int eeh_unfreeze_pe(struct eeh_pe *pe, bool sw_state);

int eeh_dev_open(struct pci_dev *pdev);

void eeh_dev_release(struct pci_dev *pdev);

struct eeh_pe *eeh_iommu_group_to_pe(struct iommu_group *group);

arch/powerpc/kernel/eeh.c

+32 −28
Original line number Diff line number Diff line
@@ -1164,6 +1164,31 @@ void eeh_remove_device(struct pci_dev *dev) 
	edev->mode &= ~EEH_DEV_SYSFS;

}



int eeh_unfreeze_pe(struct eeh_pe *pe, bool sw_state)

{

	int ret;



	ret = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);

	if (ret) {

		pr_warn("%s: Failure %d enabling IO on PHB#%x-PE#%x\n",

			__func__, ret, pe->phb->global_number, pe->addr);

		return ret;

	}



	ret = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);

	if (ret) {

		pr_warn("%s: Failure %d enabling DMA on PHB#%x-PE#%x\n",

			__func__, ret, pe->phb->global_number, pe->addr);

		return ret;

	}



	/* Clear software isolated state */

	if (sw_state && (pe->state & EEH_PE_ISOLATED))

		eeh_pe_state_clear(pe, EEH_PE_ISOLATED);



	return ret;

}



/**

 * eeh_dev_open - Increase count of pass through devices for PE

 * @pdev: PCI device
@@ -1176,7 +1201,6 @@ void eeh_remove_device(struct pci_dev *dev) 
int eeh_dev_open(struct pci_dev *pdev)

{

	struct eeh_dev *edev;

	int flag = (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE);

	int ret = -ENODEV;



	mutex_lock(&eeh_dev_mutex);
@@ -1196,31 +1220,9 @@ int eeh_dev_open(struct pci_dev *pdev) 
	 * in frozen PE won't work properly. Clear the frozen state

	 * in advance.

	 */

	ret = eeh_ops->get_state(edev->pe, NULL);

	if (ret > 0 && ret != EEH_STATE_NOT_SUPPORT &&

	    (ret & flag) != flag) {

		ret = eeh_ops->set_option(edev->pe, EEH_OPT_THAW_MMIO);

		if (ret) {

			pr_warn("%s: Failure %d enabling MMIO "

				"for PHB#%x-PE#%x\n",

				__func__, ret, edev->phb->global_number,

				edev->pe->addr);

			goto out;

		}



		ret = eeh_ops->set_option(edev->pe, EEH_OPT_THAW_DMA);

		if (ret) {

			pr_warn("%s: Failure %d enabling DMA "

				"for PHB#%x-PE#%x\n",

				__func__, ret, edev->phb->global_number,

				edev->pe->addr);

	ret = eeh_unfreeze_pe(edev->pe, true);

	if (ret)

		goto out;

		}

	}



	/* Clear software isolated state */

	if (edev->pe->state & EEH_PE_ISOLATED)

		eeh_pe_state_clear(edev->pe, EEH_PE_ISOLATED);



	/* Increase PE's pass through count */

	atomic_inc(&edev->pe->pass_dev_cnt);
@@ -1338,8 +1340,10 @@ int eeh_pe_set_option(struct eeh_pe *pe, int option) 
	 */

	switch (option) {

	case EEH_OPT_ENABLE:

		if (eeh_enabled())

		if (eeh_enabled()) {

			ret = eeh_unfreeze_pe(pe, true);

			break;

		}

		ret = -EIO;

		break;

	case EEH_OPT_DISABLE:
@@ -1351,7 +1355,7 @@ int eeh_pe_set_option(struct eeh_pe *pe, int option) 
			break;

		}



		ret = eeh_ops->set_option(pe, option);

		ret = eeh_pci_enable(pe, option);

		break;

	default:

		pr_debug("%s: Option %d out of range (%d, %d)\n",