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

[Alex Williamson <alex.williamson@redhat.com>]

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>