[PATCH] drm/amdkfd: add ACPI SRAT parsing for topology

[Zeng, Oak]

I feel such parsing work should be part of the ACPI generic work so should be done in drivers/acpi/num/srat.c (see acpi_table_parse_srat) and the acpi subsystem should expose APIs for rest drivers to query such numa information.

Regards,
Oak 

 

On 2021-04-28, 11:12 AM, "amd-gfx on behalf of Eric Huang" <amd-gfx-bounces at lists.freedesktop.org on behalf of JinHuiEric.Huang at amd.com> wrote:

    In NPS4 BIOS we need to find the closest numa node when creating
    topology io link between cpu and gpu, if PCI driver doesn't set
    it.

    Signed-off-by: Eric Huang <jinhuieric.huang at amd.com>
    ---
     drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 94 ++++++++++++++++++++++++++-
     1 file changed, 91 insertions(+), 3 deletions(-)

    diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
    index 38d45711675f..57518136c7d7 100644
    --- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
    +++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
    @@ -1759,6 +1759,87 @@ static int kfd_fill_gpu_memory_affinity(int *avail_size,
     	return 0;
     }

    +#ifdef CONFIG_ACPI
    +static void kfd_find_numa_node_in_srat(struct kfd_dev *kdev,
    +		int *numa_node)
    +{
    +	struct acpi_table_header *table_header = NULL;
    +	struct acpi_subtable_header *sub_header = NULL;
    +	unsigned long table_end, subtable_len;
    +	u32 pci_id = pci_domain_nr(kdev->pdev->bus) << 16 |
    +			pci_dev_id(kdev->pdev);
    +	u32 bdf;
    +	acpi_status status;
    +	struct acpi_srat_cpu_affinity *cpu;
    +	struct acpi_srat_generic_affinity *gpu;
    +	int pxm = 0, max_pxm = 0;
    +	bool found = false;
    +
    +	/* Fetch the SRAT table from ACPI */
    +	status = acpi_get_table(ACPI_SIG_SRAT, 0, &table_header);
    +	if (status == AE_NOT_FOUND) {
    +		pr_warn("SRAT table not found\n");
    +		return;
    +	} else if (ACPI_FAILURE(status)) {
    +		const char *err = acpi_format_exception(status);
    +		pr_err("SRAT table error: %s\n", err);
    +		return;
    +	}
    +
    +	table_end = (unsigned long)table_header + table_header->length;
    +
    +	/* Parse all entries looking for a match. */
    +
    +	sub_header = (struct acpi_subtable_header *)
    +			((unsigned long)table_header +
    +			sizeof(struct acpi_table_srat));
    +	subtable_len = sub_header->length;
    +
    +	while (((unsigned long)sub_header) + subtable_len  < table_end) {
    +		/*
    +		 * If length is 0, break from this loop to avoid
    +		 * infinite loop.
    +		 */
    +		if (subtable_len == 0) {
    +			pr_err("SRAT invalid zero length\n");
    +			break;
    +		}
    +
    +		switch (sub_header->type) {
    +		case ACPI_SRAT_TYPE_CPU_AFFINITY:
    +			cpu = (struct acpi_srat_cpu_affinity *)sub_header;
    +			pxm = *((u32 *)cpu->proximity_domain_hi) << 8 |
    +					cpu->proximity_domain_lo;
    +			if (pxm > max_pxm)
    +				max_pxm = pxm;
    +			break;
    +		case ACPI_SRAT_TYPE_GENERIC_AFFINITY:
    +			gpu = (struct acpi_srat_generic_affinity *)sub_header;
    +			bdf = *((u16 *)(&gpu->device_handle[0])) << 16 |
    +					*((u16 *)(&gpu->device_handle[2]));
    +			if (bdf == pci_id) {
    +				found = true;
    +				*numa_node = pxm_to_node(gpu->proximity_domain);
    +			}
    +			break;
    +		default:
    +			break;
    +		}
    +
    +		if (found)
    +			break;
    +
    +		sub_header = (struct acpi_subtable_header *)
    +				((unsigned long)sub_header + subtable_len);
    +		subtable_len = sub_header->length;
    +	}
    +
    +	/* workaround bad cpu-gpu binding case */
    +	if (found && (*numa_node < 0 || *numa_node > max_pxm))
    +		*numa_node = 0;
    +}
    +#endif
    +
     /* kfd_fill_gpu_direct_io_link - Fill in direct io link from GPU
      * to its NUMA node
      *	@avail_size: Available size in the memory
    @@ -1774,6 +1855,9 @@ static int kfd_fill_gpu_direct_io_link_to_cpu(int *avail_size,
     			uint32_t proximity_domain)
     {
     	struct amdgpu_device *adev = (struct amdgpu_device *)kdev->kgd;
    +#ifdef CONFIG_NUMA
    +	int numa_node = 0;
    +#endif

     	*avail_size -= sizeof(struct crat_subtype_iolink);
     	if (*avail_size < 0)
    @@ -1805,9 +1889,13 @@ static int kfd_fill_gpu_direct_io_link_to_cpu(int *avail_size,

     	sub_type_hdr->proximity_domain_from = proximity_domain;
     #ifdef CONFIG_NUMA
    -	if (kdev->pdev->dev.numa_node == NUMA_NO_NODE)
    -		sub_type_hdr->proximity_domain_to = 0;
    -	else
    +	if (kdev->pdev->dev.numa_node == NUMA_NO_NODE) {
    +#ifdef CONFIG_ACPI
    +		kfd_find_numa_node_in_srat(kdev, &numa_node);
    +#endif
    +		sub_type_hdr->proximity_domain_to = numa_node;
    +		set_dev_node(&kdev->pdev->dev, numa_node);
    +	} else
     		sub_type_hdr->proximity_domain_to = kdev->pdev->dev.numa_node;
     #else
     	sub_type_hdr->proximity_domain_to = 0;
    -- 
    2.17.1

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