diff options
author | Alex Williamson <alex.williamson@redhat.com> | 2024-04-01 10:52:55 -0600 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-13 12:59:19 +0200 |
commit | 561d5e1998d58b54ce2bbbb3e843b669aa0b3db5 (patch) | |
tree | fabc411e847224b93a13e55fa2cccaa7e873eb0e | |
parent | cfb786b03b03c5ff38882bee38525eb9987e4d14 (diff) | |
download | chromeos-561d5e1998d58b54ce2bbbb3e843b669aa0b3db5.tar.gz |
vfio/pci: Disable auto-enable of exclusive INTx IRQ
[ Upstream commit fe9a7082684eb059b925c535682e68c34d487d43 ]
Currently for devices requiring masking at the irqchip for INTx, ie.
devices without DisINTx support, the IRQ is enabled in request_irq()
and subsequently disabled as necessary to align with the masked status
flag. This presents a window where the interrupt could fire between
these events, resulting in the IRQ incrementing the disable depth twice.
This would be unrecoverable for a user since the masked flag prevents
nested enables through vfio.
Instead, invert the logic using IRQF_NO_AUTOEN such that exclusive INTx
is never auto-enabled, then unmask as required.
Cc: <stable@vger.kernel.org>
Fixes: 89e1f7d4c66d ("vfio: Add PCI device driver")
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20240308230557.805580-2-alex.williamson@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/vfio/pci/vfio_pci_intrs.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 869dce5f134dd5..9e002214a45cff 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -199,8 +199,15 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd) vdev->ctx[0].trigger = trigger; + /* + * Devices without DisINTx support require an exclusive interrupt, + * IRQ masking is performed at the IRQ chip. The masked status is + * protected by vdev->irqlock. Setup the IRQ without auto-enable and + * unmask as necessary below under lock. DisINTx is unmodified by + * the IRQ configuration and may therefore use auto-enable. + */ if (!vdev->pci_2_3) - irqflags = 0; + irqflags = IRQF_NO_AUTOEN; ret = request_irq(pdev->irq, vfio_intx_handler, irqflags, vdev->ctx[0].name, vdev); @@ -211,13 +218,9 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd) return ret; } - /* - * INTx disable will stick across the new irq setup, - * disable_irq won't. - */ spin_lock_irqsave(&vdev->irqlock, flags); - if (!vdev->pci_2_3 && vdev->ctx[0].masked) - disable_irq_nosync(pdev->irq); + if (!vdev->pci_2_3 && !vdev->ctx[0].masked) + enable_irq(pdev->irq); spin_unlock_irqrestore(&vdev->irqlock, flags); return 0; |