Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cf0921be authored by KarimAllah Ahmed's avatar KarimAllah Ahmed Committed by Bjorn Helgaas
Browse files

PCI/IOV: Use VF0 cached config registers for other VFs 



Cache some config data from VF0 and use it for all other VFs instead of
reading it from the config space of each VF.  We assume these items are the
same across all associated VFs:

   Revision ID
   Class Code
   Subsystem Vendor ID
   Subsystem ID

This is an optimization when enabling SR-IOV on a device with many VFs.

Signed-off-by: default avatarKarimAllah Ahmed <karahmed@amazon.de>
[bhelgaas: changelog, simplify comments, remove unused "device", test
CONFIG_PCI_IOV instead of CONFIG_PCI_ATS, rename functions]
Signed-off-by: default avatarBjorn Helgaas <helgaas@kernel.org>
parent bf4447fd

drivers/pci/iov.c

+35 −7
Original line number Diff line number Diff line
@@ -114,6 +114,29 @@ resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno) 
	return dev->sriov->barsz[resno - PCI_IOV_RESOURCES];

}



static void pci_read_vf_config_common(struct pci_dev *virtfn)

{

	struct pci_dev *physfn = virtfn->physfn;



	/*

	 * Some config registers are the same across all associated VFs.

	 * Read them once from VF0 so we can skip reading them from the

	 * other VFs.

	 *

	 * PCIe r4.0, sec 9.3.4.1, technically doesn't require all VFs to

	 * have the same Revision ID and Subsystem ID, but we assume they

	 * do.

	 */

	pci_read_config_dword(virtfn, PCI_CLASS_REVISION,

			      &physfn->sriov->class);

	pci_read_config_byte(virtfn, PCI_HEADER_TYPE,

			     &physfn->sriov->hdr_type);

	pci_read_config_word(virtfn, PCI_SUBSYSTEM_VENDOR_ID,

			     &physfn->sriov->subsystem_vendor);

	pci_read_config_word(virtfn, PCI_SUBSYSTEM_ID,

			     &physfn->sriov->subsystem_device);

}



int pci_iov_add_virtfn(struct pci_dev *dev, int id)

{

	int i;
@@ -136,13 +159,17 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) 
	virtfn->devfn = pci_iov_virtfn_devfn(dev, id);

	virtfn->vendor = dev->vendor;

	virtfn->device = iov->vf_device;

	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 failed0;

		goto failed1;



	virtfn->dev.parent = dev->dev.parent;

	virtfn->physfn = pci_dev_get(dev);

	virtfn->is_virtfn = 1;

	virtfn->multifunction = 0;



	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
@@ -163,10 +190,10 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) 
	sprintf(buf, "virtfn%u", id);

	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);

	if (rc)

		goto failed1;

		goto failed2;

	rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");

	if (rc)

		goto failed2;

		goto failed3;



	kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
@@ -174,11 +201,12 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) 


	return 0;



failed2:

failed3:

	sysfs_remove_link(&dev->dev.kobj, buf);

failed2:

	pci_stop_and_remove_bus_device(virtfn);

failed1:

	pci_dev_put(dev);

	pci_stop_and_remove_bus_device(virtfn);

failed0:

	virtfn_remove_bus(dev->bus, bus);

failed:

drivers/pci/pci.h

+4 −0
Original line number Diff line number Diff line
@@ -271,6 +271,10 @@ struct pci_sriov { 
	u16		driver_max_VFs;	/* Max num VFs driver supports */

	struct pci_dev	*dev;		/* Lowest numbered PF */

	struct pci_dev	*self;		/* This PF */

	u32		class;		/* VF device */

	u8		hdr_type;	/* VF header type */

	u16		subsystem_vendor; /* VF subsystem vendor */

	u16		subsystem_device; /* VF subsystem device */

	resource_size_t	barsz[PCI_SRIOV_NUM_BARS];	/* VF BAR size */

	bool		drivers_autoprobe; /* Auto probing of VFs by driver */

};

drivers/pci/probe.c

+42 −5
Original line number Diff line number Diff line
@@ -1400,6 +1400,43 @@ int pci_cfg_space_size(struct pci_dev *dev) 
	return PCI_CFG_SPACE_SIZE;

}



static u32 pci_class(struct pci_dev *dev)

{

	u32 class;



#ifdef CONFIG_PCI_IOV

	if (dev->is_virtfn)

		return dev->physfn->sriov->class;

#endif

	pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);

	return class;

}



static void pci_subsystem_ids(struct pci_dev *dev, u16 *vendor, u16 *device)

{

#ifdef CONFIG_PCI_IOV

	if (dev->is_virtfn) {

		*vendor = dev->physfn->sriov->subsystem_vendor;

		*device = dev->physfn->sriov->subsystem_device;

		return;

	}

#endif

	pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, vendor);

	pci_read_config_word(dev, PCI_SUBSYSTEM_ID, device);

}



static u8 pci_hdr_type(struct pci_dev *dev)

{

	u8 hdr_type;



#ifdef CONFIG_PCI_IOV

	if (dev->is_virtfn)

		return dev->physfn->sriov->hdr_type;

#endif

	pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type);

	return hdr_type;

}



#define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)



static void pci_msi_setup_pci_dev(struct pci_dev *dev)
@@ -1465,8 +1502,7 @@ int pci_setup_device(struct pci_dev *dev) 
	struct pci_bus_region region;

	struct resource *res;



	if (pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type))

		return -EIO;

	hdr_type = pci_hdr_type(dev);



	dev->sysdata = dev->bus->sysdata;

	dev->dev.parent = dev->bus->bridge;
@@ -1488,7 +1524,8 @@ int pci_setup_device(struct pci_dev *dev) 
		     dev->bus->number, PCI_SLOT(dev->devfn),

		     PCI_FUNC(dev->devfn));



	pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);

	class = pci_class(dev);



	dev->revision = class & 0xff;

	dev->class = class >> 8;		    /* upper 3 bytes */
@@ -1528,8 +1565,8 @@ int pci_setup_device(struct pci_dev *dev) 
			goto bad;

		pci_read_irq(dev);

		pci_read_bases(dev, 6, PCI_ROM_ADDRESS);

		pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);

		pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device);



		pci_subsystem_ids(dev, &dev->subsystem_vendor, &dev->subsystem_device);



		/*

		 * Do the ugly legacy mode stuff here rather than broken chip