On Wed, 27 Mar 2024 07:41:33 -0400 Sasha Levin <sashal@xxxxxxxxxx> wrote: > This is a note to let you know that I've just added the patch titled > > vfio/pci: Prepare for dynamic interrupt context storage > > to the 6.1-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > vfio-pci-prepare-for-dynamic-interrupt-context-stora.patch > and it can be found in the queue-6.1 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > > commit bca808da62c6a87ef168554caa318c2801d19b70 > Author: Reinette Chatre <reinette.chatre@xxxxxxxxx> > Date: Thu May 11 08:44:30 2023 -0700 > > vfio/pci: Prepare for dynamic interrupt context storage > > [ Upstream commit d977e0f7663961368f6442589e52d27484c2f5c2 ] > > Interrupt context storage is statically allocated at the time > interrupts are allocated. Following allocation, the interrupt > context is managed by directly accessing the elements of the > array using the vector as index. > > It is possible to allocate additional MSI-X vectors after > MSI-X has been enabled. Dynamic storage of interrupt context > is needed to support adding new MSI-X vectors after initial > allocation. > > Replace direct access of array elements with pointers to the > array elements. Doing so reduces impact of moving to a new data > structure. Move interactions with the array to helpers to > mostly contain changes needed to transition to a dynamic > data structure. > > No functional change intended. > > Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx> > Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> > Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > Link: https://lore.kernel.org/r/eab289693c8325ede9aba99380f8b8d5143980a4.1683740667.git.reinette.chatre@xxxxxxxxx > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> > Stable-dep-of: fe9a7082684e ("vfio/pci: Disable auto-enable of exclusive INTx IRQ") > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> ... > @@ -171,15 +225,24 @@ static irqreturn_t vfio_intx_handler(int irq, void *dev_id) > > static int vfio_intx_enable(struct vfio_pci_core_device *vdev) > { > + struct vfio_pci_irq_ctx *ctx; > + int ret; > + > if (!is_irq_none(vdev)) > return -EINVAL; > > if (!vdev->pdev->irq) > return -ENODEV; > > - vdev->ctx = kzalloc(sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL_ACCOUNT); > - if (!vdev->ctx) > - return -ENOMEM; > + ret = vfio_irq_ctx_alloc_num(vdev, 1); > + if (ret) > + return ret; > + > + ctx = vfio_irq_ctx_get(vdev, 0); > + if (!ctx) { > + vfio_irq_ctx_free_all(vdev); > + return -EINVAL; > + } > > vdev->num_ctx = 1; This is broken on it's own, vfio_irq_ctx_get() depends on a valid num_ctx, therefore this function always returns -EINVAL. This was resolved upstream by b156e48fffa9 ("vfio/pci: Use xarray for interrupt context storage") which was from the same series, so this issue was never apparent upstream. Suggest dropping this and fe9a7082684e ("vfio/pci: Disable auto-enable of exclusive INTx IRQ") for now and we'll try to rework the latter to remove the dependency. Thanks, Alex
