On Wed, Apr 09, 2025 at 02:45:23PM +0800, Jiqian Chen wrote:
> Add a new function to emulate extended capability list for host,
> and call it in init_header(). So that, it will be easy to hide
> a capability whose initialization fails.
>
> As for the extended capability list of guest, keep hiding it.
>
> Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
> ---
> cc: "Roger Pau Monné" <roger....@citrix.com>
> ---
> v1->v2 changes:
> new patch
>
> Best regards,
> Jiqian Chen.
> ---
> xen/drivers/vpci/header.c | 44 ++++++++++++++++++++++++++++++++-------
> 1 file changed, 36 insertions(+), 8 deletions(-)
>
> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
> index 0910eb940e23..6833d456566b 100644
> --- a/xen/drivers/vpci/header.c
> +++ b/xen/drivers/vpci/header.c
> @@ -815,6 +815,39 @@ static int vpci_init_capability_list(struct pci_dev
> *pdev)
> return rc;
> }
>
> +static int vpci_init_ext_capability_list(struct pci_dev *pdev)
> +{
> + int rc;
> + u32 header;
uint32_t would be preferred.
> + unsigned int pos = 0x100U, ttl = 480;
> +
> + if ( !is_hardware_domain(pdev->domain) )
> + {
> + /* Extended capabilities read as zero, write ignore */
> + rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
> + pos, 4, (void *)0);
> + if ( rc )
> + return rc;
I think you want to unconditionally return here, otherwise you will
most likely add a duplicated handler over "pos" when going inside the
loop below?
Also for domU we don't want to expose any extended capabilities yet.
> + }
> +
> + while ( pos && ttl-- )
> + {
> + header = pci_conf_read32(pdev->sbdf, pos);
> +
> + rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
You don't want to pass NULL here, as that would prevent dom0 from
writing to the register, you instead want to pass vpci_hw_write32 I
think.
> + pos, 4, (void *)(uintptr_t)header);
> + if ( rc )
> + return rc;
> +
> + if ( (header == 0) || (header == -1) )
> + return 0;
> +
> + pos = PCI_EXT_CAP_NEXT(header);
Don't you need to check that pos >= 0x100? Possibly done in the while
loop condition: while ( pos >= 0x100 && ... )
Thanks, Roger.
