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[PATCH v4 2/2] xen-pciback: allow compiling on other archs than x86



From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.
Re-structure the driver in a way that it can be built for other
platforms as well.

Add new configuration option CONFIG_XEN_PCIDEV_STUB, so the driver
can be limited in its functionality, e.g. no support for
para-virtualised scenario when it acts as PCI backend.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND
for the fully featured backend driver.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@xxxxxxxx>

---
Since v3:
 - Fix >>32 shift for 32-bit architectures
 - Move CONFIG_XEN_PCIDEV_STUB into this patch
Since v2:
 - swap the patch order
Since v1:
 - Do not move pci_xen_initial_domain as it is x86 specific
---
 arch/x86/include/asm/xen/pci.h              | 16 -----
 arch/x86/pci/xen.c                          | 74 +-------------------
 drivers/xen/Kconfig                         | 20 ++++++
 drivers/xen/pci.c                           | 75 +++++++++++++++++++++
 drivers/xen/xen-pciback/conf_space_header.c |  8 ++-
 drivers/xen/xen-pciback/pci_stub.c          |  3 +-
 drivers/xen/xen-pciback/xenbus.c            |  2 +-
 include/xen/pci.h                           | 28 ++++++++
 8 files changed, 133 insertions(+), 93 deletions(-)
 create mode 100644 include/xen/pci.h

diff --git a/arch/x86/include/asm/xen/pci.h b/arch/x86/include/asm/xen/pci.h
index 3506d8c598c1..4b08c2b809ea 100644
--- a/arch/x86/include/asm/xen/pci.h
+++ b/arch/x86/include/asm/xen/pci.h
@@ -16,27 +16,11 @@ static inline int pci_xen_hvm_init(void)
 #endif
 #if defined(CONFIG_XEN_DOM0)
 int __init pci_xen_initial_domain(void);
-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 __init pci_xen_initial_domain(void)
 {
        return -1;
 }
-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)
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 3d41a09c2c14..4a45b0bf9ae4 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -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>
@@ -583,77 +584,4 @@ int __init pci_xen_initial_domain(void)
        }
        return 0;
 }
-
-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
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 4efc95ddda41..75b9330dc6fd 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -184,6 +184,26 @@ config SWIOTLB_XEN
 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
diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 224df03ce42e..fc8c1249d49f 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -254,3 +254,78 @@ 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
diff --git a/drivers/xen/xen-pciback/conf_space_header.c 
b/drivers/xen/xen-pciback/conf_space_header.c
index ac45cdc38e85..981435103af1 100644
--- a/drivers/xen/xen-pciback/conf_space_header.c
+++ b/drivers/xen/xen-pciback/conf_space_header.c
@@ -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;
                }
        }
diff --git a/drivers/xen/xen-pciback/pci_stub.c 
b/drivers/xen/xen-pciback/pci_stub.c
index f8e4faa96ad6..bba527620507 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -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"
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index f8ba2903a3ff..bde63ef677b8 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -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)
diff --git a/include/xen/pci.h b/include/xen/pci.h
new file mode 100644
index 000000000000..b8337cf85fd1
--- /dev/null
+++ b/include/xen/pci.h
@@ -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
-- 
2.25.1




 


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