Commit b5401a96 authored by Alex Nixon's avatar Alex Nixon Committed by Konrad Rzeszutek Wilk
Browse files

xen/x86/PCI: Add support for the Xen PCI subsystem 



The frontend stub lives in arch/x86/pci/xen.c, alongside other
sub-arch PCI init code (e.g. olpc.c).

It provides a mechanism for Xen PCI frontend to setup/destroy
legacy interrupts, MSI/MSI-X, and PCI configuration operations.

[ Impact: add core of Xen PCI support ]
[ v2: Removed the IOMMU code and only focusing on PCI.]
[ v3: removed usage of pci_scan_all_fns as that does not exist]
[ v4: introduced pci_xen value to fix compile warnings]
[ v5: squished fixes+features in one patch, changed Reviewed-by to Ccs]
[ v7: added Acked-by]
Signed-off-by: default avatarAlex Nixon <alex.nixon@citrix.com>
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Qing He <qing.he@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
parent 294ee6f8

arch/x86/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -1898,6 +1898,11 @@ config PCI_OLPC 
	def_bool y

	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)



config PCI_XEN

	def_bool y

	depends on PCI && XEN

	select SWIOTLB_XEN



config PCI_DOMAINS

	def_bool y

	depends on PCI

arch/x86/include/asm/xen/pci.h

0 → 100644
+53 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_XEN_PCI_H

#define _ASM_X86_XEN_PCI_H



#if defined(CONFIG_PCI_XEN)

extern int __init pci_xen_init(void);

#define pci_xen 1

#else

#define pci_xen 0

#define pci_xen_init (0)

#endif



#if defined(CONFIG_PCI_MSI)

#if defined(CONFIG_PCI_XEN)

/* The drivers/pci/xen-pcifront.c sets this structure to

 * its own functions.

 */

struct xen_pci_frontend_ops {

	int (*enable_msi)(struct pci_dev *dev, int **vectors);

	void (*disable_msi)(struct pci_dev *dev);

	int (*enable_msix)(struct pci_dev *dev, int **vectors, int nvec);

	void (*disable_msix)(struct pci_dev *dev);

};



extern struct xen_pci_frontend_ops *xen_pci_frontend;



static inline int xen_pci_frontend_enable_msi(struct pci_dev *dev,

					      int **vectors)

{

	if (xen_pci_frontend && xen_pci_frontend->enable_msi)

		return xen_pci_frontend->enable_msi(dev, vectors);

	return -ENODEV;

}

static inline void xen_pci_frontend_disable_msi(struct pci_dev *dev)

{

	if (xen_pci_frontend && xen_pci_frontend->disable_msi)

			xen_pci_frontend->disable_msi(dev);

}

static inline int xen_pci_frontend_enable_msix(struct pci_dev *dev,

					       int **vectors, int nvec)

{

	if (xen_pci_frontend && xen_pci_frontend->enable_msix)

		return xen_pci_frontend->enable_msix(dev, vectors, nvec);

	return -ENODEV;

}

static inline void xen_pci_frontend_disable_msix(struct pci_dev *dev)

{

	if (xen_pci_frontend && xen_pci_frontend->disable_msix)

			xen_pci_frontend->disable_msix(dev);

}

#endif /* CONFIG_PCI_XEN */

#endif /* CONFIG_PCI_MSI */



#endif	/* _ASM_X86_XEN_PCI_H */

arch/x86/pci/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ obj-$(CONFIG_PCI_BIOS) += pcbios.o 
obj-$(CONFIG_PCI_MMCONFIG)	+= mmconfig_$(BITS).o direct.o mmconfig-shared.o

obj-$(CONFIG_PCI_DIRECT)	+= direct.o

obj-$(CONFIG_PCI_OLPC)		+= olpc.o

obj-$(CONFIG_PCI_XEN)		+= xen.o



obj-y				+= fixup.o

obj-$(CONFIG_ACPI)		+= acpi.o

arch/x86/pci/xen.c

0 → 100644
+147 −0
Original line number Diff line number Diff line 
/*

 * Xen PCI Frontend Stub - puts some "dummy" functions in to the Linux

 *			   x86 PCI core to support the Xen PCI Frontend

 *

 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>

 */

#include <linux/module.h>

#include <linux/init.h>

#include <linux/pci.h>

#include <linux/acpi.h>



#include <linux/io.h>

#include <asm/pci_x86.h>



#include <asm/xen/hypervisor.h>



#include <xen/events.h>

#include <asm/xen/pci.h>



#if defined(CONFIG_PCI_MSI)

#include <linux/msi.h>



struct xen_pci_frontend_ops *xen_pci_frontend;

EXPORT_SYMBOL_GPL(xen_pci_frontend);



/*

 * For MSI interrupts we have to use drivers/xen/event.s functions to

 * allocate an irq_desc and setup the right */





static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)

{

	int irq, ret, i;

	struct msi_desc *msidesc;

	int *v;



	v = kzalloc(sizeof(int) * max(1, nvec), GFP_KERNEL);

	if (!v)

		return -ENOMEM;



	if (!xen_initial_domain()) {

		if (type == PCI_CAP_ID_MSIX)

			ret = xen_pci_frontend_enable_msix(dev, &v, nvec);

		else

			ret = xen_pci_frontend_enable_msi(dev, &v);

		if (ret)

			goto error;

	}

	i = 0;

	list_for_each_entry(msidesc, &dev->msi_list, list) {

		irq = xen_allocate_pirq(v[i], 0, /* not sharable */

			(type == PCI_CAP_ID_MSIX) ?

			"pcifront-msi-x" : "pcifront-msi");

		if (irq < 0)

			return -1;



		ret = set_irq_msi(irq, msidesc);

		if (ret)

			goto error_while;

		i++;

	}

	kfree(v);

	return 0;



error_while:

	unbind_from_irqhandler(irq, NULL);

error:

	if (ret == -ENODEV)

		dev_err(&dev->dev, "Xen PCI frontend has not registered" \

			" MSI/MSI-X support!\n");



	kfree(v);

	return ret;

}



static void xen_teardown_msi_irqs(struct pci_dev *dev)

{

	/* Only do this when were are in non-privileged mode.*/

	if (!xen_initial_domain()) {

		struct msi_desc *msidesc;



		msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);

		if (msidesc->msi_attrib.is_msix)

			xen_pci_frontend_disable_msix(dev);

		else

			xen_pci_frontend_disable_msi(dev);

	}



}



static void xen_teardown_msi_irq(unsigned int irq)

{

	xen_destroy_irq(irq);

}

#endif



static int xen_pcifront_enable_irq(struct pci_dev *dev)

{

	int rc;

	int share = 1;



	dev_info(&dev->dev, "Xen PCI enabling IRQ: %d\n", dev->irq);



	if (dev->irq < 0)

		return -EINVAL;



	if (dev->irq < NR_IRQS_LEGACY)

		share = 0;



	rc = xen_allocate_pirq(dev->irq, share, "pcifront");

	if (rc < 0) {

		dev_warn(&dev->dev, "Xen PCI IRQ: %d, failed to register:%d\n",

			 dev->irq, rc);

		return rc;

	}

	return 0;

}



int __init pci_xen_init(void)

{

	if (!xen_pv_domain() || xen_initial_domain())

		return -ENODEV;



	printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");



	pcibios_set_cache_line_size();



	pcibios_enable_irq = xen_pcifront_enable_irq;

	pcibios_disable_irq = NULL;



#ifdef CONFIG_ACPI

	/* Keep ACPI out of the picture */

	acpi_noirq = 1;

#endif



#ifdef CONFIG_ISAPNP

	/* Stop isapnp from probing */

	isapnp_disable = 1;

#endif



#ifdef CONFIG_PCI_MSI

	x86_msi.setup_msi_irqs = xen_setup_msi_irqs;

	x86_msi.teardown_msi_irq = xen_teardown_msi_irq;

	x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;

#endif

	return 0;

}

arch/x86/xen/enlighten.c

+3 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ 
#include <asm/paravirt.h>

#include <asm/apic.h>

#include <asm/page.h>

#include <asm/xen/pci.h>

#include <asm/xen/hypercall.h>

#include <asm/xen/hypervisor.h>

#include <asm/fixmap.h>
@@ -1220,6 +1221,8 @@ asmlinkage void __init xen_start_kernel(void) 
		add_preferred_console("xenboot", 0, NULL);

		add_preferred_console("tty", 0, NULL);

		add_preferred_console("hvc", 0, NULL);

		if (pci_xen)

			x86_init.pci.arch_init = pci_xen_init;

	} else {

		/* Make sure ACS will be enabled */

		pci_request_acs();

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