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Blame SOURCES/kvm-vfio-pci-Enable-device-request-notification-support.patch

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From 3e7a0ab48e4cd233caf8ab9e2593d1d2978bad9d Mon Sep 17 00:00:00 2001
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From: Alex Williamson <alex.williamson@redhat.com>
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Date: Fri, 10 Apr 2015 16:34:19 +0200
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Subject: [PATCH 08/14] vfio-pci: Enable device request notification support
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Message-id: <20150410163419.15324.17072.stgit@gimli.home>
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Patchwork-id: 64788
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O-Subject: [RHEL7.2 qemu-kvm PATCH 8/8] vfio-pci: Enable device request notification support
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Bugzilla: 1210509
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RH-Acked-by: Thomas Huth <thuth@redhat.com>
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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RH-Acked-by: Bandan Das <bsd@redhat.com>
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Upstream: 47cbe50cc8d8e59129311bcdb827e1116e935bde
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Linux v4.0-rc1 vfio-pci introduced a new virtual interrupt to allow
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the kernel to request a device from the user.  When signaled, QEMU
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will by default attmempt to hot-unplug the device.  This is a one-
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shot attempt with the expectation that the kernel will continue to
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poll for the device if it is not returned.  Returning the device when
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requested is the expected standard model of cooperative usage, but we
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also add an option option to disable this feature.  Initially this
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opt-out is set as an experimental option because we really should
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honor kernel requests for the device.
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Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/misc/vfio.c             | 100 +++++++++++++++++++++++++++++++++++++++++++++
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 linux-headers/linux/vfio.h |   1 +
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 2 files changed, 101 insertions(+)
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diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
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index d06b485..cbc9d8a 100644
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--- a/hw/misc/vfio.c
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+++ b/hw/misc/vfio.c
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@@ -195,14 +195,18 @@ typedef struct VFIODevice {
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     QLIST_ENTRY(VFIODevice) next;
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     struct VFIOGroup *group;
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     EventNotifier err_notifier;
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+    EventNotifier req_notifier;
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     uint32_t features;
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 #define VFIO_FEATURE_ENABLE_VGA_BIT 0
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 #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT)
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+#define VFIO_FEATURE_ENABLE_REQ_BIT 1
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+#define VFIO_FEATURE_ENABLE_REQ (1 << VFIO_FEATURE_ENABLE_REQ_BIT)
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     int32_t bootindex;
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     uint8_t pm_cap;
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     bool reset_works;
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     bool has_vga;
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     bool pci_aer;
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+    bool req_enabled;
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     bool has_flr;
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     bool has_pm_reset;
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     bool needs_reset;
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@@ -3595,6 +3599,7 @@ static int vfio_get_device(VFIOGroup *group, const char *name, VFIODevice *vdev)
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         vdev->has_vga = true;
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     }
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+
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     irq_info.index = VFIO_PCI_ERR_IRQ_INDEX;
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     ret = ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
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@@ -3737,6 +3742,97 @@ static void vfio_unregister_err_notifier(VFIODevice *vdev)
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     event_notifier_cleanup(&vdev->err_notifier);
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 }
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+static void vfio_req_notifier_handler(void *opaque)
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+{
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+    VFIODevice *vdev = opaque;
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+
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+    if (!event_notifier_test_and_clear(&vdev->req_notifier)) {
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+        return;
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+    }
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+
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+    qdev_unplug(&vdev->pdev.qdev, NULL);
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+}
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+
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+static void vfio_register_req_notifier(VFIODevice *vdev)
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+{
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+    struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info),
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+                                      .index = VFIO_PCI_REQ_IRQ_INDEX };
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+    int argsz;
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+    struct vfio_irq_set *irq_set;
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+    int32_t *pfd;
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+
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+    if (!(vdev->features & VFIO_FEATURE_ENABLE_REQ)) {
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+        return;
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+    }
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+
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+    if (ioctl(vdev->fd,
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+              VFIO_DEVICE_GET_IRQ_INFO, &irq_info) < 0 || irq_info.count < 1) {
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+        return;
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+    }
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+
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+    if (event_notifier_init(&vdev->req_notifier, 0)) {
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+        error_report("vfio: Unable to init event notifier for device request");
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+        return;
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+    }
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+
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+    argsz = sizeof(*irq_set) + sizeof(*pfd);
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+
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+    irq_set = g_malloc0(argsz);
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+    irq_set->argsz = argsz;
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+    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
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+                     VFIO_IRQ_SET_ACTION_TRIGGER;
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+    irq_set->index = VFIO_PCI_REQ_IRQ_INDEX;
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+    irq_set->start = 0;
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+    irq_set->count = 1;
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+    pfd = (int32_t *)&irq_set->data;
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+
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+    *pfd = event_notifier_get_fd(&vdev->req_notifier);
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+    qemu_set_fd_handler(*pfd, vfio_req_notifier_handler, NULL, vdev);
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+
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+    if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
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+        error_report("vfio: Failed to set up device request notification");
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+        qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
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+        event_notifier_cleanup(&vdev->req_notifier);
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+    } else {
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+        vdev->req_enabled = true;
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+    }
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+
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+    g_free(irq_set);
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+}
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+
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+static void vfio_unregister_req_notifier(VFIODevice *vdev)
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+{
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+    int argsz;
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+    struct vfio_irq_set *irq_set;
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+    int32_t *pfd;
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+
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+    if (!vdev->req_enabled) {
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+        return;
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+    }
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+
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+    argsz = sizeof(*irq_set) + sizeof(*pfd);
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+
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+    irq_set = g_malloc0(argsz);
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+    irq_set->argsz = argsz;
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+    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
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+                     VFIO_IRQ_SET_ACTION_TRIGGER;
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+    irq_set->index = VFIO_PCI_REQ_IRQ_INDEX;
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+    irq_set->start = 0;
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+    irq_set->count = 1;
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+    pfd = (int32_t *)&irq_set->data;
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+    *pfd = -1;
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+
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+    if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
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+        error_report("vfio: Failed to de-assign device request fd: %m");
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+    }
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+    g_free(irq_set);
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+    qemu_set_fd_handler(event_notifier_get_fd(&vdev->req_notifier),
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+                        NULL, NULL, vdev);
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+    event_notifier_cleanup(&vdev->req_notifier);
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+
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+    vdev->req_enabled = false;
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+}
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+
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 static int vfio_initfn(PCIDevice *pdev)
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 {
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     VFIODevice *pvdev, *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
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@@ -3889,6 +3985,7 @@ static int vfio_initfn(PCIDevice *pdev)
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     add_boot_device_path(vdev->bootindex, &pdev->qdev, NULL);
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     vfio_register_err_notifier(vdev);
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+    vfio_register_req_notifier(vdev);
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     return 0;
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@@ -3908,6 +4005,7 @@ static void vfio_exitfn(PCIDevice *pdev)
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     VFIODevice *vdev = DO_UPCAST(VFIODevice, pdev, pdev);
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     VFIOGroup *group = vdev->group;
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+    vfio_unregister_req_notifier(vdev);
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     vfio_unregister_err_notifier(vdev);
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     pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
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     vfio_disable_interrupts(vdev);
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@@ -3962,6 +4060,8 @@ static Property vfio_pci_dev_properties[] = {
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                        intx.mmap_timeout, 1100),
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     DEFINE_PROP_BIT("x-vga", VFIODevice, features,
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                     VFIO_FEATURE_ENABLE_VGA_BIT, false),
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+    DEFINE_PROP_BIT("x-req", VFIODevice, features,
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+                    VFIO_FEATURE_ENABLE_REQ_BIT, true),
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     DEFINE_PROP_INT32("bootindex", VFIODevice, bootindex, -1),
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     /*
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      * TODO - support passed fds... is this necessary?
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diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h
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index 7919c76..d197fd4 100644
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--- a/linux-headers/linux/vfio.h
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+++ b/linux-headers/linux/vfio.h
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@@ -321,6 +321,7 @@ enum {
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 	VFIO_PCI_MSI_IRQ_INDEX,
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 	VFIO_PCI_MSIX_IRQ_INDEX,
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 	VFIO_PCI_ERR_IRQ_INDEX,
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+	VFIO_PCI_REQ_IRQ_INDEX,
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 	VFIO_PCI_NUM_IRQS
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 };
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-- 
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1.8.3.1
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