From 8effc395c2097e258fcedfc02ed4a66d45fb4238 Mon Sep 17 00:00:00 2001
From: Alexander Duyck <alexander.h.duyck@intel.com>
Date: Sat, 21 Apr 2018 15:23:09 -0500
Subject: [PATCH] PCI/IOV: Add pci_sriov_configure_simple()
Git-commit: 8effc395c2097e258fcedfc02ed4a66d45fb4238
Patch-mainline: v4.18-rc1
References: FATE#326145
SR-IOV (Single Root I/O Virtualization) is an optional PCIe capability (see
PCIe r4.0, sec 9). A PCIe Function with the SR-IOV capability is referred
to as a PF (Physical Function). If SR-IOV is enabled on the PF, several
VFs (Virtual Functions) may be created. The VFs can be individually
assigned to virtual machines, which allows them to share a single hardware
device while being isolated from each other.
Some SR-IOV devices have resources such as queues and interrupts that must
be set up in the PF before enabling the VFs, so they require a PF driver to
do that.
Other SR-IOV devices don't require any PF setup before enabling VFs. Add a
pci_sriov_configure_simple() interface so PF drivers for such devices can
use it without repeating the VF-enabling code.
Tested-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
[bhelgaas: changelog, comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Rose <gvrose8192@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>:wq
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/pci/iov.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 2 ++
2 files changed, 38 insertions(+)
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -800,3 +800,39 @@ int pci_sriov_get_totalvfs(struct pci_de
return dev->sriov->total_VFs;
}
EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);
+
+/**
+ * pci_sriov_configure_simple - helper to configure SR-IOV
+ * @dev: the PCI device
+ * @nr_virtfn: number of virtual functions to enable, 0 to disable
+ *
+ * Enable or disable SR-IOV for devices that don't require any PF setup
+ * before enabling SR-IOV. Return value is negative on error, or number of
+ * VFs allocated on success.
+ */
+int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn)
+{
+ int rc;
+
+ might_sleep();
+
+ if (!dev->is_physfn)
+ return -ENODEV;
+
+ if (pci_vfs_assigned(dev)) {
+ pci_warn(dev, "Cannot modify SR-IOV while VFs are assigned\n");
+ return -EPERM;
+ }
+
+ if (nr_virtfn == 0) {
+ sriov_disable(dev);
+ return 0;
+ }
+
+ rc = sriov_enable(dev, nr_virtfn);
+ if (rc < 0)
+ return rc;
+
+ return nr_virtfn;
+}
+EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1979,6 +1979,7 @@ int pci_num_vf(struct pci_dev *dev);
int pci_vfs_assigned(struct pci_dev *dev);
int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
int pci_sriov_get_totalvfs(struct pci_dev *dev);
+int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn);
resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno);
void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe);
#else
@@ -2006,6 +2007,7 @@ static inline int pci_sriov_set_totalvfs
{ return 0; }
static inline int pci_sriov_get_totalvfs(struct pci_dev *dev)
{ return 0; }
+#define pci_sriov_configure_simple NULL
static inline resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
{ return 0; }
static inline void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe) { }