linux-kernel - [PATCH AUTOSEL 4.18 050/131] powerpc/pseries: fix EEH recovery of some IOV devices

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Date:   Sun, 2 Sep 2018 13:04:04 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Sam Bobroff <sbobroff@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 050/131] powerpc/pseries: fix EEH recovery of
 some IOV devices

From: Sam Bobroff <sbobroff@...ux.ibm.com>

[ Upstream commit b87b9cf4935325c98522823caeddd333022a1c62 ]

EEH recovery currently fails on pSeries for some IOV capable PCI
devices, if CONFIG_PCI_IOV is on and the hypervisor doesn't provide
certain device tree properties for the device. (Found on an IOV
capable device using the ipr driver.)

Recovery fails in pci_enable_resources() at the check on r->parent,
because r->flags is set and r->parent is not.  This state is due to
sriov_init() setting the start, end and flags members of the IOV BARs
but the parent not being set later in
pseries_pci_fixup_iov_resources(), because the
"ibm,open-sriov-vf-bar-info" property is missing.

Correct this by zeroing the resource flags for IOV BARs when they
can't be configured (this is the same method used by sriov_init() and
__pci_read_base()).

VFs cleared this way can't be enabled later, because that requires
another device tree property, "ibm,number-of-configurable-vfs" as well
as support for the RTAS function "ibm_map_pes". These are all part of
hypervisor support for IOV and it seems unlikely that a hypervisor
would ever partially, but not fully, support it. (None are currently
provided by QEMU/KVM.)

Signed-off-by: Sam Bobroff <sbobroff@...ux.ibm.com>
Reviewed-by: Bryant G. Ly <bryantly@...ux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 arch/powerpc/platforms/pseries/setup.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 8a4868a3964b..cb098e962ffe 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -647,6 +647,15 @@ void of_pci_parse_iov_addrs(struct pci_dev *dev, const int *indexes)
 	}
 }
 
+static void pseries_disable_sriov_resources(struct pci_dev *pdev)
+{
+	int i;
+
+	pci_warn(pdev, "No hypervisor support for SR-IOV on this device, IOV BARs disabled.\n");
+	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++)
+		pdev->resource[i + PCI_IOV_RESOURCES].flags = 0;
+}
+
 static void pseries_pci_fixup_resources(struct pci_dev *pdev)
 {
 	const int *indexes;
@@ -654,10 +663,10 @@ static void pseries_pci_fixup_resources(struct pci_dev *pdev)
 
 	/*Firmware must support open sriov otherwise dont configure*/
 	indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
-	if (!indexes)
-		return;
-	/* Assign the addresses from device tree*/
-	of_pci_set_vf_bar_size(pdev, indexes);
+	if (indexes)
+		of_pci_set_vf_bar_size(pdev, indexes);
+	else
+		pseries_disable_sriov_resources(pdev);
 }
 
 static void pseries_pci_fixup_iov_resources(struct pci_dev *pdev)
@@ -669,10 +678,10 @@ static void pseries_pci_fixup_iov_resources(struct pci_dev *pdev)
 		return;
 	/*Firmware must support open sriov otherwise dont configure*/
 	indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
-	if (!indexes)
-		return;
-	/* Assign the addresses from device tree*/
-	of_pci_parse_iov_addrs(pdev, indexes);
+	if (indexes)
+		of_pci_parse_iov_addrs(pdev, indexes);
+	else
+		pseries_disable_sriov_resources(pdev);
 }
 
 static resource_size_t pseries_pci_iov_resource_alignment(struct pci_dev *pdev,
-- 
2.17.1