![Alex Williamson](/assets/img/avatar_default.png)
The ioeventfd here is actually irqfd handling of an ioeventfd such as supported in KVM. A user is able to pre-program a device write to occur when the eventfd triggers. This is yet another instance of eventfd-irqfd triggering between KVM and vfio. The impetus for this is high frequency writes to pages which are virtualized in QEMU. Enabling this near-direct write path for selected registers within the virtualized page can improve performance and reduce overhead. Specifically this is initially targeted at NVIDIA graphics cards where the driver issues a write to an MMIO register within a virtualized region in order to allow the MSI interrupt to re-trigger. Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
161 lines
4.5 KiB
C
161 lines
4.5 KiB
C
/*
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* Copyright (C) 2012 Red Hat, Inc. All rights reserved.
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* Author: Alex Williamson <alex.williamson@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Derived from original vfio:
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* Copyright 2010 Cisco Systems, Inc. All rights reserved.
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* Author: Tom Lyon, pugs@cisco.com
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*/
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#include <linux/mutex.h>
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#include <linux/pci.h>
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#include <linux/irqbypass.h>
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#include <linux/types.h>
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#ifndef VFIO_PCI_PRIVATE_H
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#define VFIO_PCI_PRIVATE_H
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#define VFIO_PCI_OFFSET_SHIFT 40
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#define VFIO_PCI_OFFSET_TO_INDEX(off) (off >> VFIO_PCI_OFFSET_SHIFT)
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#define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
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#define VFIO_PCI_OFFSET_MASK (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)
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/* Special capability IDs predefined access */
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#define PCI_CAP_ID_INVALID 0xFF /* default raw access */
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#define PCI_CAP_ID_INVALID_VIRT 0xFE /* default virt access */
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/* Cap maximum number of ioeventfds per device (arbitrary) */
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#define VFIO_PCI_IOEVENTFD_MAX 1000
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struct vfio_pci_ioeventfd {
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struct list_head next;
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struct virqfd *virqfd;
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void __iomem *addr;
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uint64_t data;
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loff_t pos;
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int bar;
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int count;
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};
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struct vfio_pci_irq_ctx {
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struct eventfd_ctx *trigger;
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struct virqfd *unmask;
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struct virqfd *mask;
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char *name;
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bool masked;
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struct irq_bypass_producer producer;
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};
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struct vfio_pci_device;
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struct vfio_pci_region;
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struct vfio_pci_regops {
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size_t (*rw)(struct vfio_pci_device *vdev, char __user *buf,
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size_t count, loff_t *ppos, bool iswrite);
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void (*release)(struct vfio_pci_device *vdev,
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struct vfio_pci_region *region);
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};
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struct vfio_pci_region {
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u32 type;
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u32 subtype;
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const struct vfio_pci_regops *ops;
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void *data;
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size_t size;
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u32 flags;
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};
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struct vfio_pci_dummy_resource {
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struct resource resource;
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int index;
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struct list_head res_next;
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};
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struct vfio_pci_device {
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struct pci_dev *pdev;
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void __iomem *barmap[PCI_STD_RESOURCE_END + 1];
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bool bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
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u8 *pci_config_map;
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u8 *vconfig;
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struct perm_bits *msi_perm;
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spinlock_t irqlock;
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struct mutex igate;
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struct vfio_pci_irq_ctx *ctx;
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int num_ctx;
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int irq_type;
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int num_regions;
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struct vfio_pci_region *region;
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u8 msi_qmax;
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u8 msix_bar;
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u16 msix_size;
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u32 msix_offset;
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u32 rbar[7];
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bool pci_2_3;
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bool virq_disabled;
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bool reset_works;
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bool extended_caps;
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bool bardirty;
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bool has_vga;
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bool needs_reset;
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bool nointx;
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struct pci_saved_state *pci_saved_state;
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int refcnt;
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int ioeventfds_nr;
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struct eventfd_ctx *err_trigger;
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struct eventfd_ctx *req_trigger;
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struct list_head dummy_resources_list;
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struct mutex ioeventfds_lock;
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struct list_head ioeventfds_list;
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};
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#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)
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#define is_msi(vdev) (vdev->irq_type == VFIO_PCI_MSI_IRQ_INDEX)
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#define is_msix(vdev) (vdev->irq_type == VFIO_PCI_MSIX_IRQ_INDEX)
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#define is_irq_none(vdev) (!(is_intx(vdev) || is_msi(vdev) || is_msix(vdev)))
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#define irq_is(vdev, type) (vdev->irq_type == type)
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extern void vfio_pci_intx_mask(struct vfio_pci_device *vdev);
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extern void vfio_pci_intx_unmask(struct vfio_pci_device *vdev);
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extern int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev,
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uint32_t flags, unsigned index,
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unsigned start, unsigned count, void *data);
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extern ssize_t vfio_pci_config_rw(struct vfio_pci_device *vdev,
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char __user *buf, size_t count,
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loff_t *ppos, bool iswrite);
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extern ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
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size_t count, loff_t *ppos, bool iswrite);
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extern ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
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size_t count, loff_t *ppos, bool iswrite);
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extern long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
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uint64_t data, int count, int fd);
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extern int vfio_pci_init_perm_bits(void);
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extern void vfio_pci_uninit_perm_bits(void);
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extern int vfio_config_init(struct vfio_pci_device *vdev);
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extern void vfio_config_free(struct vfio_pci_device *vdev);
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extern int vfio_pci_register_dev_region(struct vfio_pci_device *vdev,
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unsigned int type, unsigned int subtype,
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const struct vfio_pci_regops *ops,
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size_t size, u32 flags, void *data);
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#ifdef CONFIG_VFIO_PCI_IGD
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extern int vfio_pci_igd_init(struct vfio_pci_device *vdev);
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#else
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static inline int vfio_pci_igd_init(struct vfio_pci_device *vdev)
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{
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return -ENODEV;
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}
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#endif
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#endif /* VFIO_PCI_PRIVATE_H */
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