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xen-pciback: allow compiling on other archs than x86

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Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implements multiple functionalities at a time,
such as:
1. It is used as a database for assignable PCI devices, e.g. xl
   pci-assignable-{add|remove|list} manipulates that list. So, whenever
   the toolstack needs to know which PCI devices can be passed through
   it reads that from the relevant sysfs entries of the pciback.
2. It is used to hold the unbound PCI devices list, e.g. when passing
   through a PCI device it needs to be unbound from the relevant device
   driver and bound to pciback (strictly speaking it is not required
   that the device is bound to pciback, but pciback is again used as a
   database of the passed through PCI devices, so we can re-bind the
   devices back to their original drivers when guest domain shuts down)
3. Device reset for the devices being passed through
4. Para-virtualised use-cases support

The para-virtualised part of the driver is not always needed as some
architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
model for PCI device passthrough.

For such use-cases make the very first step in splitting the
xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
drivers.

For that add new configuration options CONFIG_XEN_PCI_STUB and
CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
functionality, e.g. no support for para-virtualised scenario.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
fully featured backend driver.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211028143620.144936-1-andr2000@gmail.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Oleksandr Andrushchenko 2021-10-28 17:36:20 +03:00 committed by Boris Ostrovsky
parent e453f872b7
commit a67efff288
11 changed files with 156 additions and 100 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
arch/x86/include/asm/xen/pci.h
View File

@ -22,25 +22,6 @@ static inline int __init pci_xen_initial_domain(void)
return -1;
}
#endif
#ifdef CONFIG_XEN_DOM0
int xen_find_device_domain_owner(struct pci_dev *dev);
int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);
int xen_unregister_device_domain_owner(struct pci_dev *dev);
#else
static inline int xen_find_device_domain_owner(struct pci_dev *dev)
{
return -1;
}
static inline int xen_register_device_domain_owner(struct pci_dev *dev,
uint16_t domain)
{
return -1;
}
static inline int xen_unregister_device_domain_owner(struct pci_dev *dev)
{
return -1;
}
#endif
#if defined(CONFIG_PCI_MSI)
#if defined(CONFIG_PCI_XEN)

76
arch/x86/pci/xen.c
View File

@ -23,6 +23,7 @@
#include <xen/features.h>
#include <xen/events.h>
#include <xen/pci.h>
#include <asm/xen/pci.h>
#include <asm/xen/cpuid.h>
#include <asm/apic.h>
@ -585,78 +586,3 @@ int __init pci_xen_initial_domain(void)
}
#endif
#ifdef CONFIG_XEN_DOM0
struct xen_device_domain_owner {
domid_t domain;
struct pci_dev *dev;
struct list_head list;
};
static DEFINE_SPINLOCK(dev_domain_list_spinlock);
static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);
static struct xen_device_domain_owner *find_device(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
list_for_each_entry(owner, &dev_domain_list, list) {
if (owner->dev == dev)
return owner;
}
return NULL;
}
int xen_find_device_domain_owner(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
int domain = -ENODEV;
spin_lock(&dev_domain_list_spinlock);
owner = find_device(dev);
if (owner)
domain = owner->domain;
spin_unlock(&dev_domain_list_spinlock);
return domain;
}
EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);
int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)
{
struct xen_device_domain_owner *owner;
owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
if (!owner)
return -ENODEV;
spin_lock(&dev_domain_list_spinlock);
if (find_device(dev)) {
spin_unlock(&dev_domain_list_spinlock);
kfree(owner);
return -EEXIST;
}
owner->domain = domain;
owner->dev = dev;
list_add_tail(&owner->list, &dev_domain_list);
spin_unlock(&dev_domain_list_spinlock);
return 0;
}
EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);
int xen_unregister_device_domain_owner(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
spin_lock(&dev_domain_list_spinlock);
owner = find_device(dev);
if (!owner) {
spin_unlock(&dev_domain_list_spinlock);
return -ENODEV;
}
list_del(&owner->list);
spin_unlock(&dev_domain_list_spinlock);
kfree(owner);
return 0;
}
EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);
#endif /* CONFIG_XEN_DOM0 */

24
drivers/xen/Kconfig
View File

@ -181,10 +181,34 @@ config SWIOTLB_XEN
select DMA_OPS
select SWIOTLB
config XEN_PCI_STUB
bool
config XEN_PCIDEV_STUB
tristate "Xen PCI-device stub driver"
depends on PCI && !X86 && XEN
depends on XEN_BACKEND
select XEN_PCI_STUB
default m
help
The PCI device stub driver provides limited version of the PCI
device backend driver without para-virtualized support for guests.
If you select this to be a module, you will need to make sure no
other driver has bound to the device(s) you want to make visible to
other guests.
The "hide" parameter (only applicable if backend driver is compiled
into the kernel) allows you to bind the PCI devices to this module
from the default device drivers. The argument is the list of PCI BDFs:
xen-pciback.hide=(03:00.0)(04:00.0)
If in doubt, say m.
config XEN_PCIDEV_BACKEND
tristate "Xen PCI-device backend driver"
depends on PCI && X86 && XEN
depends on XEN_BACKEND
select XEN_PCI_STUB
default m
help
The PCI device backend driver allows the kernel to export arbitrary

2
drivers/xen/Makefile
View File

@ -24,7 +24,7 @@ obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o
obj-$(CONFIG_XEN_PVHVM_GUEST) += platform-pci.o
obj-$(CONFIG_SWIOTLB_XEN) += swiotlb-xen.o
obj-$(CONFIG_XEN_MCE_LOG) += mcelog.o
obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback/
obj-$(CONFIG_XEN_PCI_STUB) += xen-pciback/
obj-$(CONFIG_XEN_PRIVCMD) += xen-privcmd.o
obj-$(CONFIG_XEN_ACPI_PROCESSOR) += xen-acpi-processor.o
obj-$(CONFIG_XEN_EFI) += efi.o

76
drivers/xen/pci.c
View File

@ -8,6 +8,7 @@
#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/pci-acpi.h>
#include <xen/pci.h>
#include <xen/xen.h>
#include <xen/interface/physdev.h>
#include <xen/interface/xen.h>
@ -254,3 +255,78 @@ static int xen_mcfg_late(void)
return 0;
}
#endif
#ifdef CONFIG_XEN_DOM0
struct xen_device_domain_owner {
domid_t domain;
struct pci_dev *dev;
struct list_head list;
};
static DEFINE_SPINLOCK(dev_domain_list_spinlock);
static struct list_head dev_domain_list = LIST_HEAD_INIT(dev_domain_list);
static struct xen_device_domain_owner *find_device(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
list_for_each_entry(owner, &dev_domain_list, list) {
if (owner->dev == dev)
return owner;
}
return NULL;
}
int xen_find_device_domain_owner(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
int domain = -ENODEV;
spin_lock(&dev_domain_list_spinlock);
owner = find_device(dev);
if (owner)
domain = owner->domain;
spin_unlock(&dev_domain_list_spinlock);
return domain;
}
EXPORT_SYMBOL_GPL(xen_find_device_domain_owner);
int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain)
{
struct xen_device_domain_owner *owner;
owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
if (!owner)
return -ENODEV;
spin_lock(&dev_domain_list_spinlock);
if (find_device(dev)) {
spin_unlock(&dev_domain_list_spinlock);
kfree(owner);
return -EEXIST;
}
owner->domain = domain;
owner->dev = dev;
list_add_tail(&owner->list, &dev_domain_list);
spin_unlock(&dev_domain_list_spinlock);
return 0;
}
EXPORT_SYMBOL_GPL(xen_register_device_domain_owner);
int xen_unregister_device_domain_owner(struct pci_dev *dev)
{
struct xen_device_domain_owner *owner;
spin_lock(&dev_domain_list_spinlock);
owner = find_device(dev);
if (!owner) {
spin_unlock(&dev_domain_list_spinlock);
return -ENODEV;
}
list_del(&owner->list);
spin_unlock(&dev_domain_list_spinlock);
kfree(owner);
return 0;
}
EXPORT_SYMBOL_GPL(xen_unregister_device_domain_owner);
#endif

7
drivers/xen/xen-pciback/Makefile
View File

@ -1,5 +1,12 @@
# SPDX-License-Identifier: GPL-2.0
# N.B. The below cannot be expressed with a single line using
# CONFIG_XEN_PCI_STUB as it always remains in "y" state,
# thus preventing the driver to be built as a module.
# Please note, that CONFIG_XEN_PCIDEV_BACKEND and
# CONFIG_XEN_PCIDEV_STUB are mutually exclusive.
obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback.o
obj-$(CONFIG_XEN_PCIDEV_STUB) += xen-pciback.o
xen-pciback-y := pci_stub.o pciback_ops.o xenbus.o
xen-pciback-y += conf_space.o conf_space_header.o \

8
drivers/xen/xen-pciback/conf_space_header.c
View File

@ -236,8 +236,12 @@ static void *bar_init(struct pci_dev *dev, int offset)
else {
pos = (offset - PCI_BASE_ADDRESS_0) / 4;
if (pos && (res[pos - 1].flags & IORESOURCE_MEM_64)) {
bar->val = res[pos - 1].start >> 32;
bar->len_val = -resource_size(&res[pos - 1]) >> 32;
/*
* Use ">> 16 >> 16" instead of direct ">> 32" shift
* to avoid warnings on 32-bit architectures.
*/
bar->val = res[pos - 1].start >> 16 >> 16;
bar->len_val = -resource_size(&res[pos - 1]) >> 16 >> 16;
return bar;
}
}

3
drivers/xen/xen-pciback/pci_stub.c
View File

@ -19,7 +19,8 @@
#include <linux/sched.h>
#include <linux/atomic.h>
#include <xen/events.h>
#include <asm/xen/pci.h>
#include <xen/pci.h>
#include <xen/xen.h>
#include <asm/xen/hypervisor.h>
#include <xen/interface/physdev.h>
#include "pciback.h"

5
drivers/xen/xen-pciback/pciback.h
View File

@ -71,6 +71,11 @@ struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev,
struct pci_dev *dev);
void pcistub_put_pci_dev(struct pci_dev *dev);
static inline bool xen_pcibk_pv_support(void)
{
return IS_ENABLED(CONFIG_XEN_PCIDEV_BACKEND);
}
/* Ensure a device is turned off or reset */
void xen_pcibk_reset_device(struct pci_dev *pdev);

8
drivers/xen/xen-pciback/xenbus.c
View File

@ -14,7 +14,7 @@
#include <linux/workqueue.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <asm/xen/pci.h>
#include <xen/pci.h>
#include "pciback.h"
#define INVALID_EVTCHN_IRQ (-1)
@ -743,6 +743,9 @@ const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
int __init xen_pcibk_xenbus_register(void)
{
if (!xen_pcibk_pv_support())
return 0;
xen_pcibk_backend = &xen_pcibk_vpci_backend;
if (passthrough)
xen_pcibk_backend = &xen_pcibk_passthrough_backend;
@ -752,5 +755,6 @@ int __init xen_pcibk_xenbus_register(void)
void __exit xen_pcibk_xenbus_unregister(void)
{
xenbus_unregister_driver(&xen_pcibk_driver);
if (xen_pcibk_pv_support())
xenbus_unregister_driver(&xen_pcibk_driver);
}

28
include/xen/pci.h Normal file
View File

@ -0,0 +1,28 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __XEN_PCI_H__
#define __XEN_PCI_H__
#if defined(CONFIG_XEN_DOM0)
int xen_find_device_domain_owner(struct pci_dev *dev);
int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain);
int xen_unregister_device_domain_owner(struct pci_dev *dev);
#else
static inline int xen_find_device_domain_owner(struct pci_dev *dev)
{
return -1;
}
static inline int xen_register_device_domain_owner(struct pci_dev *dev,
uint16_t domain)
{
return -1;
}
static inline int xen_unregister_device_domain_owner(struct pci_dev *dev)
{
return -1;
}
#endif
#endif