Re: [PATCH] perf/x86/intel/uncore: Add Node ID mask

[Song Liu <songliubraving@fb.com>]

> On Jan 27, 2019, at 6:53 AM, kan.liang@linux.intel.com wrote:
> 
> From: Kan Liang <kan.liang@linux.intel.com>
> 
> Some PCI uncore PMUs cannot be registered on a 8-socket system (HPE
> Superdome Flex).
> 
> To understand which Socket the PCI uncore PMUs belong to, perf retrieves
> the local Node ID of the uncore device from CPUNODEID(0xC0) of the PCI
> configuration space, and the mapping between Socket ID and Node ID from
> GIDNIDMAP(0xD4). The Socket ID can be calculated accordingly.
> The local Node ID is only available at bit 2:0, but current code doesn't
> mask it. If a BIOS doesn't clear the rest of the bits, a wrong Node ID
> will be fetched.
> 
> Filter the Node ID by adding a mask.
> 
> Fixes: 7c94ee2e0917 ("perf/x86: Add Intel Nehalem and Sandy Bridge-EP uncore support")
> Reported-by: Song Liu <songliubraving@fb.com>
> Tested-by: Song Liu <songliubraving@fb.com>
> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
> Cc: stable@vger.kernel.org

Thanks Kan!

Acked-by: Song Liu <songliubraving@fb.com>


> ---
> arch/x86/events/intel/uncore_snbep.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index c07bee3..b10e043 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -1222,6 +1222,8 @@ static struct pci_driver snbep_uncore_pci_driver = {
> 	.id_table	= snbep_uncore_pci_ids,
> };
> 
> +#define NODE_ID_MASK	0x7
> +
> /*
>  * build pci bus to socket mapping
>  */
> @@ -1243,7 +1245,7 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
> 		err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
> 		if (err)
> 			break;
> -		nodeid = config;
> +		nodeid = config & NODE_ID_MASK;
> 		/* get the Node ID mapping */
> 		err = pci_read_config_dword(ubox_dev, idmap_loc, &config);
> 		if (err)
> -- 
> 2.7.4
>