The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Thanks, Sasha
------------------ original commit in Linus's tree ------------------
From 7447d911af699a15f8d050dfcb7c680a86f87012 Mon Sep 17 00:00:00 2001 From: Alex Williamson alex.williamson@redhat.com Date: Fri, 8 Mar 2024 16:05:28 -0700 Subject: [PATCH] vfio/fsl-mc: Block calling interrupt handler without trigger
The eventfd_ctx trigger pointer of the vfio_fsl_mc_irq object is initially NULL and may become NULL if the user sets the trigger eventfd to -1. The interrupt handler itself is guaranteed that trigger is always valid between request_irq() and free_irq(), but the loopback testing mechanisms to invoke the handler function need to test the trigger. The triggering and setting ioctl paths both make use of igate and are therefore mutually exclusive.
The vfio-fsl-mc driver does not make use of irqfds, nor does it support any sort of masking operations, therefore unlike vfio-pci and vfio-platform, the flow can remain essentially unchanged.
Cc: Diana Craciun diana.craciun@oss.nxp.com Cc: stable@vger.kernel.org Fixes: cc0ee20bd969 ("vfio/fsl-mc: trigger an interrupt via eventfd") Reviewed-by: Kevin Tian kevin.tian@intel.com Reviewed-by: Eric Auger eric.auger@redhat.com Link: https://lore.kernel.org/r/20240308230557.805580-8-alex.williamson@redhat.com Signed-off-by: Alex Williamson alex.williamson@redhat.com --- drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c index d62fbfff20b82..82b2afa9b7e31 100644 --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c @@ -141,13 +141,14 @@ static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev, irq = &vdev->mc_irqs[index];
if (flags & VFIO_IRQ_SET_DATA_NONE) { - vfio_fsl_mc_irq_handler(hwirq, irq); + if (irq->trigger) + eventfd_signal(irq->trigger);
} else if (flags & VFIO_IRQ_SET_DATA_BOOL) { u8 trigger = *(u8 *)data;
- if (trigger) - vfio_fsl_mc_irq_handler(hwirq, irq); + if (trigger && irq->trigger) + eventfd_signal(irq->trigger); }
return 0;