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authorEric Auger <eric.auger@linaro.org>2015-10-05 12:30:12 -0600
committerAlex Williamson <alex.williamson@redhat.com>2015-10-05 12:30:12 -0600
commit58892b447f0ffcd0967bc6f1bcb40df288ebeebc (patch)
tree2607a56a41cd816c75f9070310567fb31a3f0603
parentc0b520dfb8890294a9f8879f4759172900585995 (diff)
downloadqemu-arm-58892b447f0ffcd0967bc6f1bcb40df288ebeebc.tar.gz
hw/vfio/platform: irqfd setup sequence update
With current implementation, eventfd VFIO signaling is first set up and then irqfd is setup, if supported and allowed. This start sequence causes several issues with IRQ forwarding setup which, if supported, is transparently attempted on irqfd setup: IRQ forwarding setup is likely to fail if the IRQ is detected as under injection into the guest (active at irqchip level or VFIO masked). This currently always happens because the current sequence explicitly VFIO-masks the IRQ before setting irqfd. Even if that masking were removed, we couldn't prevent the case where the IRQ is under injection into the guest. So the simpler solution is to remove this 2-step startup and directly attempt irqfd setup. This is what this patch does. Also in case the eventfd setup fails, there is no reason to go farther: let's abort. Signed-off-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
-rw-r--r--hw/vfio/platform.c51
1 files changed, 29 insertions, 22 deletions
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index a6726cd779..d864342bf1 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -310,18 +310,29 @@ static void vfio_platform_eoi(VFIODevice *vbasedev)
/**
* vfio_start_eventfd_injection - starts the virtual IRQ injection using
* user-side handled eventfds
- * @intp: the IRQ struct pointer
+ * @sbdev: the sysbus device handle
+ * @irq: the qemu irq handle
*/
-static int vfio_start_eventfd_injection(VFIOINTp *intp)
+static void vfio_start_eventfd_injection(SysBusDevice *sbdev, qemu_irq irq)
{
int ret;
+ VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
+ VFIOINTp *intp;
+
+ QLIST_FOREACH(intp, &vdev->intp_list, next) {
+ if (intp->qemuirq == irq) {
+ break;
+ }
+ }
+ assert(intp);
ret = vfio_set_trigger_eventfd(intp, vfio_intp_interrupt);
if (ret) {
- error_report("vfio: Error: Failed to pass IRQ fd to the driver: %m");
+ error_report("vfio: failed to start eventfd signaling for IRQ %d: %m",
+ intp->pin);
+ abort();
}
- return ret;
}
/*
@@ -359,6 +370,15 @@ static int vfio_set_resample_eventfd(VFIOINTp *intp)
return ret;
}
+/**
+ * vfio_start_irqfd_injection - starts the virtual IRQ injection using
+ * irqfd
+ *
+ * @sbdev: the sysbus device handle
+ * @irq: the qemu irq handle
+ *
+ * In case the irqfd setup fails, we fallback to userspace handled eventfd
+ */
static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
{
VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
@@ -366,7 +386,7 @@ static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
if (!kvm_irqfds_enabled() || !kvm_resamplefds_enabled() ||
!vdev->irqfd_allowed) {
- return;
+ goto fail_irqfd;
}
QLIST_FOREACH(intp, &vdev->intp_list, next) {
@@ -376,13 +396,6 @@ static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
}
assert(intp);
- /* Get to a known interrupt state */
- qemu_set_fd_handler(event_notifier_get_fd(&intp->interrupt),
- NULL, NULL, vdev);
-
- vfio_mask_single_irqindex(&vdev->vbasedev, intp->pin);
- qemu_set_irq(intp->qemuirq, 0);
-
if (kvm_irqchip_add_irqfd_notifier(kvm_state, &intp->interrupt,
&intp->unmask, irq) < 0) {
goto fail_irqfd;
@@ -395,9 +408,6 @@ static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
goto fail_vfio;
}
- /* Let's resume injection with irqfd setup */
- vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin);
-
intp->kvm_accel = true;
trace_vfio_platform_start_irqfd_injection(intp->pin,
@@ -406,9 +416,11 @@ static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
return;
fail_vfio:
kvm_irqchip_remove_irqfd_notifier(kvm_state, &intp->interrupt, irq);
+ error_report("vfio: failed to start eventfd signaling for IRQ %d: %m",
+ intp->pin);
+ abort();
fail_irqfd:
- vfio_start_eventfd_injection(intp);
- vfio_unmask_single_irqindex(&vdev->vbasedev, intp->pin);
+ vfio_start_eventfd_injection(sbdev, irq);
return;
}
@@ -646,7 +658,6 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp)
VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev);
SysBusDevice *sbdev = SYS_BUS_DEVICE(dev);
VFIODevice *vbasedev = &vdev->vbasedev;
- VFIOINTp *intp;
int i, ret;
vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM;
@@ -665,10 +676,6 @@ static void vfio_platform_realize(DeviceState *dev, Error **errp)
vfio_map_region(vdev, i);
sysbus_init_mmio(sbdev, &vdev->regions[i]->mem);
}
-
- QLIST_FOREACH(intp, &vdev->intp_list, next) {
- vfio_start_eventfd_injection(intp);
- }
}
static const VMStateDescription vfio_platform_vmstate = {