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![Konrad Rzeszutek Wilk](/assets/img/avatar_default.png)
As commit 0a9fd01529
'xen/pciback: Document the entry points for 'pcistub_put_pci_dev''
explained there are four entry points in this function.
Two of them are when the user fiddles in the SysFS to
unbind a device which might be in use by a guest or not.
Both 'unbind' states will cause a deadlock as the the PCI lock has
already been taken, which then pci_device_reset tries to take.
We can simplify this by requiring that all callers of
pcistub_put_pci_dev MUST hold the device lock. And then
we can just call the lockless version of pci_device_reset.
To make it even simpler we will modify xen_pcibk_release_pci_dev
to quality whether it should take a lock or not - as it ends
up calling xen_pcibk_release_pci_dev and needs to hold the lock.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
193 lines
6.2 KiB
C
193 lines
6.2 KiB
C
/*
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* PCI Backend Common Data Structures & Function Declarations
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*
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* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
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*/
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#ifndef __XEN_PCIBACK_H__
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#define __XEN_PCIBACK_H__
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#include <linux/pci.h>
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#include <linux/interrupt.h>
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#include <xen/xenbus.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <linux/atomic.h>
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#include <xen/interface/io/pciif.h>
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#define DRV_NAME "xen-pciback"
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struct pci_dev_entry {
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struct list_head list;
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struct pci_dev *dev;
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};
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#define _PDEVF_op_active (0)
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#define PDEVF_op_active (1<<(_PDEVF_op_active))
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#define _PCIB_op_pending (1)
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#define PCIB_op_pending (1<<(_PCIB_op_pending))
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struct xen_pcibk_device {
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void *pci_dev_data;
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struct mutex dev_lock;
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struct xenbus_device *xdev;
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struct xenbus_watch be_watch;
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u8 be_watching;
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int evtchn_irq;
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struct xen_pci_sharedinfo *sh_info;
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unsigned long flags;
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struct work_struct op_work;
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};
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struct xen_pcibk_dev_data {
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struct list_head config_fields;
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struct pci_saved_state *pci_saved_state;
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unsigned int permissive:1;
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unsigned int warned_on_write:1;
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unsigned int enable_intx:1;
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unsigned int isr_on:1; /* Whether the IRQ handler is installed. */
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unsigned int ack_intr:1; /* .. and ACK-ing */
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unsigned long handled;
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unsigned int irq; /* Saved in case device transitions to MSI/MSI-X */
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char irq_name[0]; /* xen-pcibk[000:04:00.0] */
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};
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/* Used by XenBus and xen_pcibk_ops.c */
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extern wait_queue_head_t xen_pcibk_aer_wait_queue;
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extern struct workqueue_struct *xen_pcibk_wq;
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/* Used by pcistub.c and conf_space_quirks.c */
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extern struct list_head xen_pcibk_quirks;
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/* Get/Put PCI Devices that are hidden from the PCI Backend Domain */
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struct pci_dev *pcistub_get_pci_dev_by_slot(struct xen_pcibk_device *pdev,
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int domain, int bus,
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int slot, int func);
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struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev,
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struct pci_dev *dev);
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void pcistub_put_pci_dev(struct pci_dev *dev);
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/* Ensure a device is turned off or reset */
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void xen_pcibk_reset_device(struct pci_dev *pdev);
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/* Access a virtual configuration space for a PCI device */
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int xen_pcibk_config_init(void);
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int xen_pcibk_config_init_dev(struct pci_dev *dev);
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void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev);
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void xen_pcibk_config_reset_dev(struct pci_dev *dev);
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void xen_pcibk_config_free_dev(struct pci_dev *dev);
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int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
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u32 *ret_val);
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int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size,
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u32 value);
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/* Handle requests for specific devices from the frontend */
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typedef int (*publish_pci_dev_cb) (struct xen_pcibk_device *pdev,
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unsigned int domain, unsigned int bus,
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unsigned int devfn, unsigned int devid);
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typedef int (*publish_pci_root_cb) (struct xen_pcibk_device *pdev,
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unsigned int domain, unsigned int bus);
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/* Backend registration for the two types of BDF representation:
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* vpci - BDFs start at 00
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* passthrough - BDFs are exactly like in the host.
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*/
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struct xen_pcibk_backend {
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const char *name;
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int (*init)(struct xen_pcibk_device *pdev);
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void (*free)(struct xen_pcibk_device *pdev);
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int (*find)(struct pci_dev *pcidev, struct xen_pcibk_device *pdev,
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unsigned int *domain, unsigned int *bus,
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unsigned int *devfn);
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int (*publish)(struct xen_pcibk_device *pdev, publish_pci_root_cb cb);
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void (*release)(struct xen_pcibk_device *pdev, struct pci_dev *dev,
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bool lock);
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int (*add)(struct xen_pcibk_device *pdev, struct pci_dev *dev,
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int devid, publish_pci_dev_cb publish_cb);
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struct pci_dev *(*get)(struct xen_pcibk_device *pdev,
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unsigned int domain, unsigned int bus,
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unsigned int devfn);
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};
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extern const struct xen_pcibk_backend xen_pcibk_vpci_backend;
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extern const struct xen_pcibk_backend xen_pcibk_passthrough_backend;
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extern const struct xen_pcibk_backend *xen_pcibk_backend;
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static inline int xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
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struct pci_dev *dev,
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int devid,
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publish_pci_dev_cb publish_cb)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->add)
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return xen_pcibk_backend->add(pdev, dev, devid, publish_cb);
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return -1;
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}
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static inline void xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
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struct pci_dev *dev, bool lock)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->release)
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return xen_pcibk_backend->release(pdev, dev, lock);
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}
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static inline struct pci_dev *
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xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev, unsigned int domain,
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unsigned int bus, unsigned int devfn)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->get)
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return xen_pcibk_backend->get(pdev, domain, bus, devfn);
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return NULL;
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}
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/**
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* Add for domain0 PCIE-AER handling. Get guest domain/bus/devfn in xen_pcibk
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* before sending aer request to pcifront, so that guest could identify
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* device, coopearte with xen_pcibk to finish aer recovery job if device driver
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* has the capability
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*/
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static inline int xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
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struct xen_pcibk_device *pdev,
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unsigned int *domain,
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unsigned int *bus,
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unsigned int *devfn)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->find)
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return xen_pcibk_backend->find(pcidev, pdev, domain, bus,
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devfn);
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return -1;
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}
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static inline int xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->init)
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return xen_pcibk_backend->init(pdev);
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return -1;
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}
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static inline int xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
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publish_pci_root_cb cb)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->publish)
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return xen_pcibk_backend->publish(pdev, cb);
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return -1;
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}
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static inline void xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
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{
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if (xen_pcibk_backend && xen_pcibk_backend->free)
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return xen_pcibk_backend->free(pdev);
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}
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/* Handles events from front-end */
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irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id);
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void xen_pcibk_do_op(struct work_struct *data);
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int xen_pcibk_xenbus_register(void);
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void xen_pcibk_xenbus_unregister(void);
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extern int verbose_request;
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void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev);
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#endif
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/* Handles shared IRQs that can to device domain and control domain. */
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void xen_pcibk_irq_handler(struct pci_dev *dev, int reset);
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