[PATCH V10 11/12] powerpc/eeh: Don't block PCI config on resetting VF PE

[Wei Yang]

From: Gavin Shan <gwshan at linux.vnet.ibm.com>

When passing through SRIOV VF from host to guest via VFIO PCI
infrastructure, the VF is resetted by EEH specific backend
(pcibios_set_pcie_reset_state()). We can't block the PCI config,
otherwise, the reset (FLR or AF FLR), to be completed by PCI
config access to the VF, can't be done. Then the VF can't be
put into initial state when passing it to the guest and returning
back to the host.

The patch just doesn't block the VF's PCI config space when doing
the reset. It fixes EEH error caused by DMA traffic to bogus DMA
address on restarting guest after killing the QEMU process, which
includes Mellanox VF passed through from host.

Reported-by: Alexey Kardashevskiy <aik at ozlabs.ru>
Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
Tested-by: Alexey Kardashevskiy <aik at ozlabs.ru>
Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
---
 arch/powerpc/kernel/eeh.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 28e4d73..e1846f5 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -745,7 +745,8 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state stat
 	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);
+		if (!(pe->type & EEH_PE_VF))
+			eeh_pe_state_clear(pe, EEH_PE_CFG_BLOCKED);
 		eeh_pe_dev_traverse(pe, eeh_restore_dev_state, dev);
 		eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
 		break;
@@ -753,14 +754,16 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state stat
 		eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
 		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);
+		if (!(pe->type & EEH_PE_VF))
+			eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
 		eeh_ops->reset(pe, EEH_RESET_HOT);
 		break;
 	case pcie_warm_reset:
 		eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
 		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);
+		if (!(pe->type & EEH_PE_VF))
+			eeh_pe_state_mark(pe, EEH_PE_CFG_BLOCKED);
 		eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
 		break;
 	default:
-- 
2.5.0