On Thu, 12 Dec 2024 15:50:49 -0500
Yunxiang Li <Yunxiang.Li@xxxxxxx> wrote:
> In the next patch the logic for reading ROM will get more complicated,
> so decouple the ROM path from the normal path. Also check that for ROM
> write is not allowed.
This is already enforced by the caller. Vague references to the next
patch don't make a lot of sense once commits are in the tree, this
should describe what you're preparing for.
>
> Signed-off-by: Yunxiang Li <Yunxiang.Li@xxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci_rdwr.c | 47 ++++++++++++++++----------------
> 1 file changed, 24 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
> index a1eeacad82120..4bed9fd5af50f 100644
> --- a/drivers/vfio/pci/vfio_pci_rdwr.c
> +++ b/drivers/vfio/pci/vfio_pci_rdwr.c
> @@ -236,10 +236,9 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
> struct pci_dev *pdev = vdev->pdev;
> loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
> int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
> - size_t x_start = 0, x_end = 0;
> + size_t x_start, x_end;
> resource_size_t end;
> void __iomem *io;
> - struct resource *res = &vdev->pdev->resource[bar];
> ssize_t done;
>
> if (pci_resource_start(pdev, bar))
> @@ -253,41 +252,43 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
> count = min(count, (size_t)(end - pos));
>
> if (bar == PCI_ROM_RESOURCE) {
> + if (iswrite)
> + return -EINVAL;
> /*
> * The ROM can fill less space than the BAR, so we start the
> * excluded range at the end of the actual ROM. This makes
> * filling large ROM BARs much faster.
> */
> io = pci_map_rom(pdev, &x_start);
> - if (!io) {
> - done = -ENOMEM;
> - goto out;
> - }
> + if (!io)
> + return -ENOMEM;
> x_end = end;
> +
> + done = vfio_pci_core_do_io_rw(vdev, 1, io, buf, pos,
> + count, x_start, x_end, 0);
> +
> + pci_unmap_rom(pdev, io);
> } else {
> - int ret = vfio_pci_core_setup_barmap(vdev, bar);
> - if (ret) {
> - done = ret;
> - goto out;
> - }
> + done = vfio_pci_core_setup_barmap(vdev, bar);
> + if (done)
> + return done;
>
> io = vdev->barmap[bar];
> - }
>
> - if (bar == vdev->msix_bar) {
> - x_start = vdev->msix_offset;
> - x_end = vdev->msix_offset + vdev->msix_size;
> - }
> + if (bar == vdev->msix_bar) {
> + x_start = vdev->msix_offset;
> + x_end = vdev->msix_offset + vdev->msix_size;
> + } else {
> + x_start = 0;
> + x_end = 0;
> + }
There's a lot of semantic preference noise that obscures what you're
actually trying to accomplish here, effectively this has only
refactored the code to have separate calls to ..do_io_rw() for the ROM
vs other case and therefore pushed the unmap into the ROM case,
introducing various new exit paths.
>
> - done = vfio_pci_core_do_io_rw(vdev, res->flags & IORESOURCE_MEM, io, buf, pos,
> + done = vfio_pci_core_do_io_rw(vdev, pci_resource_flags(pdev, bar) & IORESOURCE_MEM, io, buf, pos,
The line is too long already, now it's indented further and the
wrapping needs to be adjusted.
> count, x_start, x_end, iswrite);
> -
> - if (done >= 0)
> - *ppos += done;
> -
> - if (bar == PCI_ROM_RESOURCE)
> - pci_unmap_rom(pdev, io);
> + }
> out:
Both goto's to this label were removed above, none added. Thanks,
Alex
> + if (done > 0)
> + *ppos += done;
> return done;
> }
>
