struct vfio_pci_core_device::num_ctx counts how many interrupt contexts have been allocated. When all interrupt contexts are allocated simultaneously num_ctx provides the upper bound of all vectors that can be used as indices into the interrupt context array. With the upcoming support for dynamic MSI-X the number of interrupt contexts does not necessarily span the range of allocated interrupts. Consequently, num_ctx is no longer a trusted upper bound for valid indices. Stop using num_ctx to determine if a provided vector is valid. Use the existence of allocated interrupt. This changes behavior on the error path when user space provides an invalid vector range. Behavior changes from early exit without any modifications to possible modifications to valid vectors within the invalid range. This is acceptable considering that an invalid range is not a valid scenario, see link to discussion. The checks that ensure that user space provides a range of vectors that is valid for the device are untouched. Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx> Link: https://lore.kernel.org/lkml/20230316155646.07ae266f.alex.williamson@xxxxxxxxxx/ --- Changes since V2: - Update changelog to reflect change in policy that existence of allocated interrupt is validity check, not existence of context (which is now dynamically allocated). Changes since RFC V1: - Remove vfio_irq_ctx_range_allocated(). (Alex and Kevin). drivers/vfio/pci/vfio_pci_intrs.c | 13 +------------ include/linux/vfio_pci_core.h | 1 - 2 files changed, 1 insertion(+), 13 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 117cd384b3ad..5e3de004f4cb 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -237,8 +237,6 @@ static int vfio_intx_enable(struct vfio_pci_core_device *vdev) if (!ctx) return -ENOMEM; - vdev->num_ctx = 1; - /* * If the virtual interrupt is masked, restore it. Devices * supporting DisINTx can be masked at the hardware level @@ -325,7 +323,6 @@ static void vfio_intx_disable(struct vfio_pci_core_device *vdev) } vfio_intx_set_signal(vdev, -1); vdev->irq_type = VFIO_PCI_NUM_IRQS; - vdev->num_ctx = 0; vfio_irq_ctx_free(vdev, ctx, 0); } @@ -361,7 +358,6 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi } vfio_pci_memory_unlock_and_restore(vdev, cmd); - vdev->num_ctx = nvec; vdev->irq_type = msix ? VFIO_PCI_MSIX_IRQ_INDEX : VFIO_PCI_MSI_IRQ_INDEX; @@ -385,9 +381,6 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev, int irq, ret; u16 cmd; - if (vector >= vdev->num_ctx) - return -EINVAL; - irq = pci_irq_vector(pdev, vector); if (irq < 0) return -EINVAL; @@ -474,9 +467,6 @@ static int vfio_msi_set_block(struct vfio_pci_core_device *vdev, unsigned start, unsigned int i, j; int ret = 0; - if (start >= vdev->num_ctx || start + count > vdev->num_ctx) - return -EINVAL; - for (i = 0, j = start; i < count && !ret; i++, j++) { int fd = fds ? fds[i] : -1; ret = vfio_msi_set_vector_signal(vdev, j, fd, msix); @@ -515,7 +505,6 @@ static void vfio_msi_disable(struct vfio_pci_core_device *vdev, bool msix) pci_intx(pdev, 0); vdev->irq_type = VFIO_PCI_NUM_IRQS; - vdev->num_ctx = 0; } /* @@ -650,7 +639,7 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev, return ret; } - if (!irq_is(vdev, index) || start + count > vdev->num_ctx) + if (!irq_is(vdev, index)) return -EINVAL; for (i = start; i < start + count; i++) { diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 61d7873a3973..148fd1ae6c1c 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -60,7 +60,6 @@ struct vfio_pci_core_device { spinlock_t irqlock; struct mutex igate; struct xarray ctx; - int num_ctx; int irq_type; int num_regions; struct vfio_pci_region *region; -- 2.34.1
