From 6178d4689a1e6a0d2b6dea1dad990e74148fa9d1 Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Wed, 21 Apr 2021 17:20:53 +0200 Subject: [PATCH] vfio-ccw: Permit missing IRQs Commit 690e29b91102 ("vfio-ccw: Refactor ccw irq handler") changed one of the checks for the IRQ notifier registration from saying "the host needs to recognize the only IRQ that exists" to saying "the host needs to recognize ANY IRQ that exists." And this worked fine, because the subsequent change to support the CRW IRQ notifier doesn't get into this code when running on an older kernel, thanks to a guard by a capability region. The later addition of the REQ(uest) IRQ by commit b2f96f9e4f5f ("vfio-ccw: Connect the device request notifier") broke this assumption because there is no matching capability region. Thus, running new QEMU on an older kernel fails with: vfio: unexpected number of irqs 2 Let's adapt the message here so that there's a better clue of what IRQ is missing. Furthermore, let's make the REQ(uest) IRQ not fail when attempting to register it, to permit running vfio-ccw on a newer QEMU with an older kernel. Fixes: b2f96f9e4f5f ("vfio-ccw: Connect the device request notifier") Signed-off-by: Eric Farman Message-Id: <20210421152053.2379873-1-farman@linux.ibm.com> Signed-off-by: Cornelia Huck --- hw/vfio/ccw.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index e752c845e9..7c058d13e8 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -411,8 +411,8 @@ static void vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev, } if (vdev->num_irqs < irq + 1) { - error_setg(errp, "vfio: unexpected number of irqs %u", - vdev->num_irqs); + error_setg(errp, "vfio: IRQ %u not available (number of irqs %u)", + irq, vdev->num_irqs); return; } @@ -695,13 +695,15 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp) vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_REQ_IRQ_INDEX, &err); if (err) { - goto out_req_notifier_err; + /* + * Report this error, but do not make it a failing condition. + * Lack of this IRQ in the host does not prevent normal operation. + */ + error_report_err(err); } return; -out_req_notifier_err: - vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_CRW_IRQ_INDEX); out_crw_notifier_err: vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX); out_io_notifier_err: -- 2.11.4.GIT