Re: [dpdk-dev] [PATCH v3] pci_vfio: Support 64KB kernel page_size with vfio-pci driver

["Tone Zhang (Arm Technology China)" <Tone.Zhang@arm.com>]

Hi all,

Could anyone please have a review and re-test the change?

Thanks a lot!

Br,
Tone

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of tone.zhang
> Sent: Monday, November 19, 2018 10:37 AM
> To: dev@dpdk.org
> Cc: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>; Honnappa
> Nagarahalli <Honnappa.Nagarahalli@arm.com>; Steve Capper
> <Steve.Capper@arm.com>; anatoly.burakov@intel.com; nd <nd@arm.com>
> Subject: [dpdk-dev] [PATCH v3] pci_vfio: Support 64KB kernel page_size with
> vfio-pci driver
> 
> With a larger PAGE_SIZE it is possible for the MSI table to very close to the end
> of the BAR s.t. when we align the start and end of the MSI table to the
> PAGE_SIZE, the end offset of the MSI table is out of the PCI BAR boundary.
> 
> This patch addresses the issue by comparing both the start and the end offset of
> the MSI table with the BAR size, and skip the mapping if it is out of Bar scope.
> 
> The patch fixes the debug log as below:
> EAL: Skipping BAR0
> 
> Signed-off-by: tone.zhang <tone.zhang@arm.com>
> Reviewed-by: Gavin Hu <Gavin.Hu@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Steve Capper <Steve.Capper@arm.com>
> Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>  drivers/bus/pci/linux/pci_vfio.c | 27 ++++++++++++++++++++++-----
>  1 file changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
> index ffd26f1..0e7bfd7 100644
> --- a/drivers/bus/pci/linux/pci_vfio.c
> +++ b/drivers/bus/pci/linux/pci_vfio.c
> @@ -457,9 +457,11 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct
> mapped_pci_resource *vfio_res,
>  	struct pci_msix_table *msix_table = &vfio_res->msix_table;
>  	struct pci_map *bar = &vfio_res->maps[bar_index];
> 
> -	if (bar->size == 0)
> +	if (bar->size == 0) {
>  		/* Skip this BAR */
> +		RTE_LOG(INFO, EAL, "Skipping BAR%d\n", bar_index);
>  		return 0;
> +	}
> 
>  	if (msix_table->bar_index == bar_index) {
>  		/*
> @@ -468,8 +470,14 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct
> mapped_pci_resource *vfio_res,
>  		 */
>  		uint32_t table_start = msix_table->offset;
>  		uint32_t table_end = table_start + msix_table->size;
> -		table_end = (table_end + ~PAGE_MASK) & PAGE_MASK;
> -		table_start &= PAGE_MASK;
> +		table_end = RTE_ALIGN(table_end, PAGE_SIZE);
> +		table_start = RTE_ALIGN(table_start, PAGE_SIZE);
> +
> +		/* If page-aligned start of MSI-X table is beyond BAR size,
> +		 * shrink the mapping size to MSI-X table start address.
> +		 */
> +		if (table_start >= bar->size)
> +			table_start = msix_table->offset;
> 
>  		if (table_start == 0 && table_end >= bar->size) {
>  			/* Cannot map this BAR */
> @@ -481,8 +489,17 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct
> mapped_pci_resource *vfio_res,
> 
>  		memreg[0].offset = bar->offset;
>  		memreg[0].size = table_start;
> -		memreg[1].offset = bar->offset + table_end;
> -		memreg[1].size = bar->size - table_end;
> +		if (bar->size < table_end) {
> +			/*
> +			 * If MSI-X table end is beyond BAR end, don't attempt
> +			 * to perform second mapping.
> +			 */
> +			memreg[1].offset = 0;
> +			memreg[1].size = 0;
> +		} else {
> +			memreg[1].offset = bar->offset + table_end;
> +			memreg[1].size = bar->size - table_end;
> +		}
> 
>  		RTE_LOG(DEBUG, EAL,
>  			"Trying to map BAR%d that contains the MSI-X "
> --
> 2.7.4