Re: [PATCH v3] pci: correct pci config size default for cap version 2 endpoints

Alex Williamson
2011-07-22T17:00:18Z

On Fri, 2011-07-22 at 11:59 -0400, Donald Dutile wrote:
> v3: remove all boundary tests. just fix the obvious bug.
> : boundary test is not necessary; get this fix in &
> post boundary test in another separate patch.
>
> v2: do local boundary check with respect to legacy PCI header length,
> and don't depend on it in pci_add_capability().
> : fix compilation, and change else>2 to simple else for all other cases.
>
> v1: first patch: boundary check in pci_add_capability().
>
> Doing device assignement using a PCIe device with it's
> PCI Cap structure at offset 0xcc showed a problem in
> the default size mapped for this cap-id.
>
> The failure caused a corruption which might have gone unnoticed
> otherwise.
>
> Fix assigned_device_pci_cap_init() to set the default
> size of PCIe Cap structure (cap-id 0x10) to 0x34 instead of 0x3c.
> 0x34 is default, min, for endpoint device with a cap version of 2.
>
> Signed-off-by: Donald Dutile <ddutile@redhat.com>
> cc: Alex Williamson <alex.williamson@redhat.com>
> cc: Michael S. Tsirkin <mst@redhat.com>
>
> tested-by: ebenes@redhat.com
>
> ---
>
> hw/device-assignment.c | 8 +++++---
> 1 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/hw/device-assignment.c b/hw/device-assignment.c
> index 36ad6b0..34db52e 100644
> --- a/hw/device-assignment.c
> +++ b/hw/device-assignment.c
> @@ -1419,16 +1419,18 @@ static int assigned_device_pci_cap_init(PCIDevice *pci_dev)
> }
>
> if ((pos = pci_find_cap_offset(pci_dev, PCI_CAP_ID_EXP, 0))) {
> - uint8_t version;
> + uint8_t version, size;
> uint16_t type, devctl, lnkcap, lnksta;
> uint32_t devcap;
> - int size = 0x3c; /* version 2 size */
>
> version = pci_get_byte(pci_dev->config + pos + PCI_EXP_FLAGS);
> version &= PCI_EXP_FLAGS_VERS;
> if (version == 1) {
> size = 0x14;
> - } else if (version > 2) {
> + } else if (version == 2) {
> + /* don't include slot cap/stat/ctrl 2 regs; only support endpoints */
> + size = 0x34;
> + } else {
> fprintf(stderr, "Unsupported PCI express capability version %d\n",
> version);
> return -EINVAL;
>

Acked-by: Alex Williamson <alex.williamson@redhat.com>