On Wed, Aug 24, 2011 at 02:29:30PM +0200, Jan Kiszka wrote:
> Nothing good can happen when we overlap capabilities. This may happen
> when plugging in assigned devices or when devices models contain bugs.
> Detect the overlap and report it.
>
> Based on qemu-kvm commit by Alex Williamson.
>
> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
Applied, thanks everyone.
> ---
> hw/pci.c | 34 ++++++++++++++++++++++++++++++++++
> 1 files changed, 34 insertions(+), 0 deletions(-)
>
> Changes in v2:
> - properly find the conflicting CAP
> - adjust error code
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 6124790..634e789 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -1811,6 +1811,25 @@ static uint8_t pci_find_capability_list(PCIDevice
> *pdev, uint8_t cap_id,
> return next;
> }
>
> +static uint8_t pci_find_capability_at_offset(PCIDevice *pdev, uint8_t offset)
> +{
> + uint8_t next, prev, found = 0;
> +
> + if (!(pdev->used[offset])) {
> + return 0;
> + }
> +
> + assert(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST);
> +
> + for (prev = PCI_CAPABILITY_LIST; (next = pdev->config[prev]);
> + prev = next + PCI_CAP_LIST_NEXT) {
> + if (next <= offset && next > found) {
> + found = next;
> + }
> + }
> + return found;
> +}
> +
> /* Patch the PCI vendor and device ids in a PCI rom image if necessary.
> This is needed for an option rom which is used for more than one device.
> */
> static void pci_patch_ids(PCIDevice *pdev, uint8_t *ptr, int size)
> @@ -1952,11 +1971,26 @@ int pci_add_capability(PCIDevice *pdev, uint8_t
> cap_id,
> uint8_t offset, uint8_t size)
> {
> uint8_t *config;
> + int i, overlapping_cap;
> +
> if (!offset) {
> offset = pci_find_space(pdev, size);
> if (!offset) {
> return -ENOSPC;
> }
> + } else {
> + for (i = offset; i < offset + size; i++) {
> + overlapping_cap = pci_find_capability_at_offset(pdev, i);
> + if (overlapping_cap) {
> + fprintf(stderr, "ERROR: %04x:%02x:%02x.%x "
> + "Attempt to add PCI capability %x at offset "
> + "%x overlaps existing capability %x at offset %x\n",
> + pci_find_domain(pdev->bus), pci_bus_num(pdev->bus),
> + PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
> + cap_id, offset, overlapping_cap, i);
> + return -EINVAL;
> + }
> + }
> }
>
> config = pdev->config + offset;
> --
> 1.7.3.4
