xen/pciback: xen pci backend driver.

This is the host side counterpart to the frontend driver in
drivers/pci/xen-pcifront.c. The PV protocol is also implemented by
frontend drivers in other OSes too, such as the BSDs.

The PV protocol is rather simple. There is page shared with the guest,
which has the 'struct xen_pci_sharedinfo' embossed in it. The backend
has a thread that is kicked every-time the structure is changed and
based on the operation field it performs specific tasks:

 XEN_PCI_OP_conf_[read|write]:
   Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c)
   Based on which field is probed, we either enable/disable the PCI
   device, change power state, read VPD, etc. The major goal of this
   call is to provide a Physical IRQ (PIRQ) to the guest.

   The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ
   is tied in to the IO-APIC, or is a vector. For GSI type
   interrupts, the PIRQ==GSI holds. For MSI/MSI-X the
   PIRQ value != Linux IRQ number (thought PIRQ==vector).

   Please note, that with Xen, all interrupts (except those level shared ones)
   are injected directly to the guest - there is no host interaction.

 XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c)
   Enables/disables the MSI/MSI-X capability of the device. These operations
   setup the MSI/MSI-X vectors for the guest and pass them to the frontend.

   When the device is activated, the interrupts are directly injected in the
   guest without involving the host.

 XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure,
  perform the appropriate AER commands on the guest. Right now that is
  a cop-out - we just kill the guest.

Besides implementing those commands, it can also

 - hide a PCI device from the host. When booting up, the user can specify
   xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the
   device.

The driver was lifted from linux-2.6.18.hg tree and fixed up
so that it could compile under v3.0. Per suggestion from Jesse Barnes
moved the driver to drivers/xen/xen-pciback.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h
new file mode 100644
index 00000000000..98e29127abf
--- /dev/null
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -0,0 +1,133 @@
+/*
+ * PCI Backend Common Data Structures & Function Declarations
+ *
+ *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+#ifndef __XEN_PCIBACK_H__
+#define __XEN_PCIBACK_H__
+
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <xen/xenbus.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <asm/atomic.h>
+#include <xen/interface/io/pciif.h>
+
+struct pci_dev_entry {
+	struct list_head list;
+	struct pci_dev *dev;
+};
+
+#define _PDEVF_op_active 	(0)
+#define PDEVF_op_active 	(1<<(_PDEVF_op_active))
+#define _PCIB_op_pending	(1)
+#define PCIB_op_pending		(1<<(_PCIB_op_pending))
+
+struct pciback_device {
+	void *pci_dev_data;
+	spinlock_t dev_lock;
+
+	struct xenbus_device *xdev;
+
+	struct xenbus_watch be_watch;
+	u8 be_watching;
+
+	int evtchn_irq;
+
+	struct xen_pci_sharedinfo *sh_info;
+
+	unsigned long flags;
+
+	struct work_struct op_work;
+};
+
+struct pciback_dev_data {
+	struct list_head config_fields;
+	int permissive;
+	int warned_on_write;
+};
+
+/* Used by XenBus and pciback_ops.c */
+extern wait_queue_head_t aer_wait_queue;
+extern struct workqueue_struct *pciback_wq;
+/* Used by pcistub.c and conf_space_quirks.c */
+extern struct list_head pciback_quirks;
+
+/* Get/Put PCI Devices that are hidden from the PCI Backend Domain */
+struct pci_dev *pcistub_get_pci_dev_by_slot(struct pciback_device *pdev,
+					    int domain, int bus,
+					    int slot, int func);
+struct pci_dev *pcistub_get_pci_dev(struct pciback_device *pdev,
+				    struct pci_dev *dev);
+void pcistub_put_pci_dev(struct pci_dev *dev);
+
+/* Ensure a device is turned off or reset */
+void pciback_reset_device(struct pci_dev *pdev);
+
+/* Access a virtual configuration space for a PCI device */
+int pciback_config_init(void);
+int pciback_config_init_dev(struct pci_dev *dev);
+void pciback_config_free_dyn_fields(struct pci_dev *dev);
+void pciback_config_reset_dev(struct pci_dev *dev);
+void pciback_config_free_dev(struct pci_dev *dev);
+int pciback_config_read(struct pci_dev *dev, int offset, int size,
+			u32 *ret_val);
+int pciback_config_write(struct pci_dev *dev, int offset, int size, u32 value);
+
+/* Handle requests for specific devices from the frontend */
+typedef int (*publish_pci_dev_cb) (struct pciback_device *pdev,
+				   unsigned int domain, unsigned int bus,
+				   unsigned int devfn, unsigned int devid);
+typedef int (*publish_pci_root_cb) (struct pciback_device *pdev,
+				    unsigned int domain, unsigned int bus);
+int pciback_add_pci_dev(struct pciback_device *pdev, struct pci_dev *dev,
+			int devid, publish_pci_dev_cb publish_cb);
+void pciback_release_pci_dev(struct pciback_device *pdev, struct pci_dev *dev);
+struct pci_dev *pciback_get_pci_dev(struct pciback_device *pdev,
+				    unsigned int domain, unsigned int bus,
+				    unsigned int devfn);
+
+/**
+* Add for domain0 PCIE-AER handling. Get guest domain/bus/devfn in pciback
+* before sending aer request to pcifront, so that guest could identify
+* device, coopearte with pciback to finish aer recovery job if device driver
+* has the capability
+*/
+
+int pciback_get_pcifront_dev(struct pci_dev *pcidev,
+			     struct pciback_device *pdev,
+			     unsigned int *domain, unsigned int *bus,
+			     unsigned int *devfn);
+int pciback_init_devices(struct pciback_device *pdev);
+int pciback_publish_pci_roots(struct pciback_device *pdev,
+			      publish_pci_root_cb cb);
+void pciback_release_devices(struct pciback_device *pdev);
+
+/* Handles events from front-end */
+irqreturn_t pciback_handle_event(int irq, void *dev_id);
+void pciback_do_op(struct work_struct *data);
+
+int pciback_xenbus_register(void);
+void pciback_xenbus_unregister(void);
+
+#ifdef CONFIG_PCI_MSI
+int pciback_enable_msi(struct pciback_device *pdev,
+			struct pci_dev *dev, struct xen_pci_op *op);
+
+int pciback_disable_msi(struct pciback_device *pdev,
+			struct pci_dev *dev, struct xen_pci_op *op);
+
+
+int pciback_enable_msix(struct pciback_device *pdev,
+			struct pci_dev *dev, struct xen_pci_op *op);
+
+int pciback_disable_msix(struct pciback_device *pdev,
+			struct pci_dev *dev, struct xen_pci_op *op);
+#endif
+extern int verbose_request;
+
+void test_and_schedule_op(struct pciback_device *pdev);
+#endif
+