On 2025/4/15 17:42, Roger Pau Monné wrote:
> 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?
Oh, it's my bad.
I should return here for any rc.
>
> 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.
Will change in next version.
>
>> + 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 && ... )
Yes, will change in next version.
>
> Thanks, Roger.
--
Best regards,
Jiqian Chen.
