linux-kernel - [PATCH] PCI/IOV: Fix VF cfg

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Date:   Tue, 04 Jun 2019 11:26:42 -0600
From:   Alex Williamson <alex.williamson@...hat.com>
To:     linux-pci@...r.kernel.org
Cc:     KarimAllah Ahmed <karahmed@...zon.de>, bhelgaas@...gle.com,
        linux-kernel@...r.kernel.org
Subject: [PATCH] PCI/IOV: Fix VF cfg_size

Commit 975bb8b4dc93 ("PCI/IOV: Use VF0 cached config space size for
other VFs") attempts to cache the config space size of VF0 to re-use
for all other VFs, but the cache is setup before the call to
pci_setup_device(), where we use set_pcie_port_type() to setup the
pcie_cap field on the struct pci_dev.  Without pcie_cap configured,
pci_cfg_space_size() returns PCI_CFG_SPACE_SIZE for the size.  VF0
has a bypass through pci_cfg_space_size(), so its size is reported
correctly, but all subsequent VFs incorrectly report 256 bytes of
config space.

Resolve by delaying pci_read_vf_config_common() until after
pci_setup_device().

Fixes: 975bb8b4dc93 ("PCI/IOV: Use VF0 cached config space size for other VFs")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1714978
Cc: KarimAllah Ahmed <karahmed@...zon.de>
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
---
 drivers/pci/iov.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 3aa115ed3a65..34b1f78f4d31 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -161,13 +161,13 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id)
 	virtfn->is_virtfn = 1;
 	virtfn->physfn = pci_dev_get(dev);

-	if (id == 0)
-		pci_read_vf_config_common(virtfn);
-
 	rc = pci_setup_device(virtfn);
 	if (rc)
 		goto failed1;

+	if (id == 0)
+		pci_read_vf_config_common(virtfn);
+
 	virtfn->dev.parent = dev->dev.parent;
 	virtfn->multifunction = 0;