[PATCH v4 2/3] vfio-pci: Add new function for INTx one-time initialisation

[Leo Yan]

To support INTx enabling for multiple times, we need firstly to extract
one-time initialisation and move the related code into a new function
vfio_pci_init_intx(); if later disable and re-enable the INTx, we can
skip these one-time operations.

This patch move below three main operations for INTx one-time
initialisation from function vfio_pci_enable_intx() into function
vfio_pci_init_intx():

- Reserve 2 FDs for INTx;
- Sanity check with ioctl VFIO_DEVICE_GET_IRQ_INFO;
- Setup pdev->intx_gsi.

Suggested-by: Jean-Philippe Brucker <jean-philippe.bruc...@arm.com>
Signed-off-by: Leo Yan <leo....@linaro.org>
Reviewed-by: Jean-Philippe Brucker <jean-philippe.bruc...@arm.com>
---
 vfio/pci.c | 67 ++++++++++++++++++++++++++++++++----------------------
 1 file changed, 40 insertions(+), 27 deletions(-)

diff --git a/vfio/pci.c b/vfio/pci.c
index 5224fee..3c39844 100644
--- a/vfio/pci.c
+++ b/vfio/pci.c
@@ -1018,30 +1018,7 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct 
vfio_device *vdev)
        struct vfio_irq_eventfd trigger;
        struct vfio_irq_eventfd unmask;
        struct vfio_pci_device *pdev = &vdev->pci;
-       int gsi = pdev->hdr.irq_line - KVM_IRQ_OFFSET;
-
-       struct vfio_irq_info irq_info = {
-               .argsz = sizeof(irq_info),
-               .index = VFIO_PCI_INTX_IRQ_INDEX,
-       };
-
-       vfio_pci_reserve_irq_fds(2);
-
-       ret = ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
-       if (ret || irq_info.count == 0) {
-               vfio_dev_err(vdev, "no INTx reported by VFIO");
-               return -ENODEV;
-       }
-
-       if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) {
-               vfio_dev_err(vdev, "interrupt not eventfd capable");
-               return -EINVAL;
-       }
-
-       if (!(irq_info.flags & VFIO_IRQ_INFO_AUTOMASKED)) {
-               vfio_dev_err(vdev, "INTx interrupt not AUTOMASKED");
-               return -EINVAL;
-       }
+       int gsi = pdev->intx_gsi;
 
        /*
         * PCI IRQ is level-triggered, so we use two eventfds. trigger_fd
@@ -1097,8 +1074,6 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct 
vfio_device *vdev)
 
        pdev->intx_fd = trigger_fd;
        pdev->unmask_fd = unmask_fd;
-       /* Guest is going to ovewrite our irq_line... */
-       pdev->intx_gsi = gsi;
 
        return 0;
 
@@ -1117,6 +1092,39 @@ err_close:
        return ret;
 }
 
+static int vfio_pci_init_intx(struct kvm *kvm, struct vfio_device *vdev)
+{
+       int ret;
+       struct vfio_pci_device *pdev = &vdev->pci;
+       struct vfio_irq_info irq_info = {
+               .argsz = sizeof(irq_info),
+               .index = VFIO_PCI_INTX_IRQ_INDEX,
+       };
+
+       vfio_pci_reserve_irq_fds(2);
+
+       ret = ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
+       if (ret || irq_info.count == 0) {
+               vfio_dev_err(vdev, "no INTx reported by VFIO");
+               return -ENODEV;
+       }
+
+       if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) {
+               vfio_dev_err(vdev, "interrupt not eventfd capable");
+               return -EINVAL;
+       }
+
+       if (!(irq_info.flags & VFIO_IRQ_INFO_AUTOMASKED)) {
+               vfio_dev_err(vdev, "INTx interrupt not AUTOMASKED");
+               return -EINVAL;
+       }
+
+       /* Guest is going to ovewrite our irq_line... */
+       pdev->intx_gsi = pdev->hdr.irq_line - KVM_IRQ_OFFSET;
+
+       return 0;
+}
+
 static int vfio_pci_configure_dev_irqs(struct kvm *kvm, struct vfio_device 
*vdev)
 {
        int ret = 0;
@@ -1142,8 +1150,13 @@ static int vfio_pci_configure_dev_irqs(struct kvm *kvm, 
struct vfio_device *vdev
                        return ret;
        }
 
-       if (pdev->irq_modes & VFIO_PCI_IRQ_MODE_INTX)
+       if (pdev->irq_modes & VFIO_PCI_IRQ_MODE_INTX) {
+               ret = vfio_pci_init_intx(kvm, vdev);
+               if (ret)
+                       return ret;
+
                ret = vfio_pci_enable_intx(kvm, vdev);
+       }
 
        return ret;
 }
-- 
2.19.1

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