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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: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Gavin Shan 2014-09-30 12:39:01 +10:00 committed by Michael Ellerman
parent 4d4f577e4b
commit 4eeeff0ebc
2 changed files with 33 additions and 28 deletions
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1
arch/powerpc/include/asm/eeh.h
View File

@ -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);

60
arch/powerpc/kernel/eeh.c
View File

@ -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);
goto out;
}
}
/* Clear software isolated state */
if (edev->pe->state & EEH_PE_ISOLATED)
eeh_pe_state_clear(edev->pe, EEH_PE_ISOLATED);
ret = eeh_unfreeze_pe(edev->pe, true);
if (ret)
goto out;
/* 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",