Re: [dpdk-kmods] windows/netuio: fix bar parsing

["Kadam, Pallavi" <pallavi.kadam@intel.com>]

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Hi Dmitry,

On 8/6/2022 2:01 PM, Dmitry Kozlyuk wrote:
> 2022-08-02 12:10 (UTC-0700), Pallavi Kadam:
>> For certain PCIe devices, BAR values are not continuous.
>> This patch maps all the BARs and avoids skipping the next BAR addresses.
>>
>> Fixes: e28aabd88279 ("windows/netuio: introduce NetUIO kernel driver")
>> Cc:navasile@microsoft.com
>>
>> Signed-off-by: Qiao Liu<qiao.liu@intel.com>
>> Signed-off-by: Pallavi Kadam<pallavi.kadam@intel.com>
>> ---
>>   windows/netuio/netuio_dev.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/windows/netuio/netuio_dev.c b/windows/netuio/netuio_dev.c
>> index b2deb10..e2cac3e 100644
>> --- a/windows/netuio/netuio_dev.c
>> +++ b/windows/netuio/netuio_dev.c
>> @@ -172,6 +172,7 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST Resources, WDFCMRESLIST R
>>       ULONG next_descriptor = 0;
>>       ULONG curr_bar = 0;
>>       ULONG prev_bar = 0;
>> +    BOOLEAN bar_done = FALSE;
>>   
>>      /*
>>       * ResourcesTranslated report MMIO BARs in the correct order, but their
>> @@ -197,7 +198,8 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST Resources, WDFCMRESLIST R
>>       for (INT bar_index = 0; bar_index < PCI_MAX_BAR; bar_index++) {
>>           prev_bar = curr_bar;
>>           curr_bar = pci_config.u.type0.BaseAddresses[bar_index];
>> -        if (curr_bar == 0 || (prev_bar & PCI_TYPE_64BIT)) {
>> +        if (curr_bar == 0 || ((prev_bar & PCI_TYPE_64BIT) && (bar_done))) {
>> +            bar_done = FALSE;
>>               continue;
>>           }
>>   
>> @@ -219,6 +221,7 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST Resources, WDFCMRESLIST R
>>           ctx->bar[bar_index].virt_addr = MmMapIoSpace(descriptor->u.Memory.Start,
>>                                                        descriptor->u.Memory.Length,
>>                                                        MmNonCached);
>> +        bar_done = TRUE;
>>           if (ctx->bar[bar_index].virt_addr == NULL) {
>>               status = STATUS_INSUFFICIENT_RESOURCES;
>>               goto end;
> Hi Pallavi,
>
> In the first place, it was wrong to always test `prev_bar & PCI_TYPE_64BIT`
> because only the first BAR slot of a 64-bit BAR contains flags.
> The current code has a state to track (curr_bar, prev_bar),
> and the fix is complicating it even more without solving the root cause.
> I suggest a simpler fix (not tested!)
> that eliminates both the incorrectness and the state to maintain:

Thank you for these changes. Will test the patch and let you know.

>
> diff --git a/windows/netuio/netuio_dev.c b/windows/netuio/netuio_dev.c
> index d4662b6..8761d31 100644
> --- a/windows/netuio/netuio_dev.c
> +++ b/windows/netuio/netuio_dev.c
> @@ -273,8 +273,6 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST
> Resources, WDFCMRESLIST R
>   
>       PCM_PARTIAL_RESOURCE_DESCRIPTOR descriptor;
>       ULONG next_descriptor = 0;
> -    ULONG curr_bar = 0;
> -    ULONG prev_bar = 0;
>   
>      /*
>       * ResourcesTranslated report MMIO BARs in the correct order, but their
> @@ -298,9 +296,9 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST
> Resources, WDFCMRESLIST R
>       * searching for the next MMIO resource each time.
>       */
>       for (INT bar_index = 0; bar_index < PCI_MAX_BAR; bar_index++) {
> -        prev_bar = curr_bar;
> -        curr_bar = pci_config.u.type0.BaseAddresses[bar_index];
> -        if (curr_bar == 0 || (prev_bar & PCI_TYPE_64BIT)) {
> +        ULONG bar_value = pci_config.u.type0.BaseAddresses[bar_index];
> +
> +        if (bar_value == 0) {
>               continue;
>           }
>   
> @@ -339,6 +337,11 @@ netuio_map_hw_resources(WDFDEVICE Device, WDFCMRESLIST
> Resources, WDFCMRESLIST R
>           }
>   
>           ctx->dpdk_hw[bar_index].mem.size = ctx->bar[bar_index].size;
> +
> +        // Skip the next BAR slot used by the current 64-bit address.
> +        if (bar_value & PCI_TYPE_64BIT) {
> +            bar_index++;
> +        }
>       } // for bar_index
>   end_of_loop:

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