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Message-ID: <c652d77b-9b5d-475e-92c5-435941fa206e@amd.com>
Date: Mon, 14 Oct 2024 15:09:16 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Borislav Petkov <bp@...en8.de>, Hans de Goede <hdegoede@...hat.com>,
x86@...nel.org, "Gautham R . Shenoy" <gautham.shenoy@....com>,
Perry Yuan <perry.yuan@....com>, LKML <linux-kernel@...r.kernel.org>,
linux-doc@...r.kernel.org, linux-pm@...r.kernel.org,
platform-driver-x86@...r.kernel.org,
Shyam Sundar S K <Shyam-sundar.S-k@....com>
Subject: Re: [PATCH v2 06/13] platform/x86: hfi: parse CPU core ranking data
from shared memory
On 10/14/2024 05:14, Ilpo Järvinen wrote:
> On Thu, 10 Oct 2024, Mario Limonciello wrote:
>
>> From: Perry Yuan <Perry.Yuan@....com>
>>
>> When `amd_hfi` driver is loaded, it will use PCCT subspace type 4 table
>> to retrieve the shared memory address which contains the CPU core ranking
>> table. This table includes a header that specifies the number of ranking
>> data entries to be parsed and rank each CPU core with the Performance and
>> Energy Efficiency capability as implemented by the CPU power management
>> firmware.
>>
>> Once the table has been parsed, each CPU is assigned a ranking score
>> within its class. Subsequently, when the scheduler selects cores, it
>> chooses from the ranking list based on the assigned scores in each class,
>> thereby ensuring the optimal selection of CPU cores according to their
>> predefined classifications and priorities.
>>
>> Signed-off-by: Perry Yuan <Perry.Yuan@....com>
>> Co-developed-by: Mario Limonciello <mario.limonciello@....com>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>> v2:
>> * Rework amd_hfi_fill_metatadata to directly use structure instead of
>> pointer math.
>> ---
>> drivers/platform/x86/amd/hfi/hfi.c | 215 ++++++++++++++++++++++++++++-
>> 1 file changed, 212 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
>> index da2e667107e8..10651399cf75 100644
>> --- a/drivers/platform/x86/amd/hfi/hfi.c
>> +++ b/drivers/platform/x86/amd/hfi/hfi.c
>> @@ -18,22 +18,78 @@
>> #include <linux/io.h>
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> +#include <linux/mailbox_client.h>
>> #include <linux/mutex.h>
>> +#include <linux/percpu-defs.h>
>> #include <linux/platform_device.h>
>> #include <linux/printk.h>
>> #include <linux/smp.h>
>> #include <linux/string.h>
>> +#include <linux/topology.h>
>> +#include <linux/workqueue.h>
>> +
>> +#include <asm/cpu_device_id.h>
>> +
>> +#include <acpi/pcc.h>
>> +#include <acpi/cppc_acpi.h>
>>
>> #define AMD_HFI_DRIVER "amd_hfi"
>> +#define AMD_HFI_MAILBOX_COUNT 1
>> +#define AMD_HETERO_RANKING_TABLE_VER 2
>> +
>> #define AMD_HETERO_CPUID_27 0x80000027
>> +
>> static struct platform_device *device;
>>
>> +/**
>> + * struct amd_shmem_info - Shared memory table for AMD HFI
>> + *
>> + * @signature: The PCC signature. The signature of a subspace is computed by
>> + * a bitwise of the value 0x50434300 with the subspace ID.
>> + * @flags: Notify on completion
>> + * @length: Length of payload being transmitted including command field
>> + * @command: Command being sent over the subspace
>> + * @version_number: Version number of the table
>> + * @n_logical_processors: Number of logical processors
>> + * @n_capabilities: Number of ranking dimensions (performance, efficiency, etc)
>> + * @table_update_context: Command being sent over the subspace
>> + * @n_bitmaps: Number of 32-bit bitmaps to enumerate all the APIC IDs
>> + * This is based on the maximum APIC ID enumerated in the system
>> + * @reserved: 24 bit spare
>> + * @table_data: Bit Map(s) of enabled logical processors
>> + * Followed by the ranking data for each logical processor
>> + */
>> +struct amd_shmem_info {
>> + struct acpi_pcct_ext_pcc_shared_memory header;
>> + u32 version_number :8,
>> + n_logical_processors :8,
>> + n_capabilities :8,
>> + table_update_context :8;
>> + u32 n_bitmaps :8,
>> + reserved :24;
>> + u32 table_data[];
>> +} __packed;
>> +
>> struct amd_hfi_data {
>> const char *name;
>> struct device *dev;
>> struct mutex lock;
>> +
>> + /* PCCT table related*/
>> + struct pcc_mbox_chan *pcc_chan;
>> + void __iomem *pcc_comm_addr;
>> + struct acpi_subtable_header *pcct_entry;
>> + struct amd_shmem_info *shmem;
>> };
>>
>> +/**
>> + * struct amd_hfi_classes - HFI class capabilities per CPU
>> + * @perf: Performance capability
>> + * @eff: Power efficiency capability
>> + *
>> + * Capabilities of a logical processor in the ranking table. These capabilities
>> + * are unitless and specific to each HFI class.
>> + */
>> struct amd_hfi_classes {
>> u32 perf;
>> u32 eff;
>> @@ -42,23 +98,105 @@ struct amd_hfi_classes {
>> /**
>> * struct amd_hfi_cpuinfo - HFI workload class info per CPU
>> * @cpu: cpu index
>> + * @apic_id: apic id of the current cpu
>> * @cpus: mask of cpus associated with amd_hfi_cpuinfo
>> * @class_index: workload class ID index
>> * @nr_class: max number of workload class supported
>> + * @ipcc_scores: ipcc scores for each class
>> * @amd_hfi_classes: current cpu workload class ranking data
>> *
>> * Parameters of a logical processor linked with hardware feedback class
>> */
>> struct amd_hfi_cpuinfo {
>> int cpu;
>> + u32 apic_id;
>> cpumask_var_t cpus;
>> s16 class_index;
>> u8 nr_class;
>> + int *ipcc_scores;
>> struct amd_hfi_classes *amd_hfi_classes;
>> };
>>
>> static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
>>
>> +static int find_cpu_index_by_apicid(unsigned int target_apicid)
>> +{
>> + int cpu_index;
>> +
>> + for_each_possible_cpu(cpu_index) {
>> + struct cpuinfo_x86 *info = &cpu_data(cpu_index);
>> +
>> + if (info->topo.apicid == target_apicid) {
>> + pr_debug("match APIC id %d for CPU index: %d",
>
> Missing \n
Ack
>
>> + info->topo.apicid, cpu_index);
>> + return cpu_index;
>> + }
>> + }
>> +
>> + return -ENODEV;
>> +}
>> +
>> +static int amd_hfi_fill_metadata(struct amd_hfi_data *amd_hfi_data)
>> +{
>> + struct acpi_pcct_ext_pcc_slave *pcct_ext =
>> + (struct acpi_pcct_ext_pcc_slave *)amd_hfi_data->pcct_entry;
>> + void __iomem *pcc_comm_addr;
>> +
>> + pcc_comm_addr = acpi_os_ioremap(amd_hfi_data->pcc_chan->shmem_base_addr,
>> + amd_hfi_data->pcc_chan->shmem_size);
>> + if (!pcc_comm_addr) {
>> + pr_err("failed to ioremap PCC common region mem\n");
>> + return -ENOMEM;
>> + }
>> +
>> + memcpy_fromio(amd_hfi_data->shmem, pcc_comm_addr, pcct_ext->length);
>> + iounmap(pcc_comm_addr);
>> +
>> + if (amd_hfi_data->shmem->header.signature != PCC_SIGNATURE) {
>> + pr_err("Invalid signature in shared memory\n");
>> + return -EINVAL;
>> + }
>> + if (amd_hfi_data->shmem->version_number != AMD_HETERO_RANKING_TABLE_VER) {
>> + pr_err("Invalid veresion %d\n", amd_hfi_data->shmem->version_number);
>
> version
Ack
>
>> + return -EINVAL;
>> + }
>> +
>> + for (u32 i = 0; i < amd_hfi_data->shmem->n_bitmaps; i++) {
>> + u32 bitmap = amd_hfi_data->shmem->table_data[i];
>> +
>> + for (u32 j = 0; j < BITS_PER_TYPE(u32); j++) {
>
> Are these u32 really the types you want to use for the loop vars, why?
I was going off the type of amd_hfi_data->shmem->n_bitmaps which is u32.
In practice I think an unsigned int should be fine though too.
>
>> + struct amd_hfi_cpuinfo *info;
>> + int apic_id = i * BITS_PER_TYPE(u32) + j;
>> + int cpu_index;
>> +
>> + if (!(bitmap & BIT(j)))
>> + continue;
>> +
>> + cpu_index = find_cpu_index_by_apicid(apic_id);
>> + if (cpu_index < 0) {
>> + pr_warn("APIC ID %d not found\n", apic_id);
>> + continue;
>> + }
>> +
>> + info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
>> + info->apic_id = apic_id;
>> +
>> + /* Fill the ranking data for each logical processor */
>> + info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
>> + for (int k = 0; k < info->nr_class; k++) {
>
> unsigned int
>
>> + u32 *table = amd_hfi_data->shmem->table_data +
>> + amd_hfi_data->shmem->n_bitmaps +
>> + i * info->nr_class;
>> +
>> + info->amd_hfi_classes[k].eff = table[apic_id + 2 * k];
>> + info->amd_hfi_classes[k].perf = table[apic_id + 2 * k + 1];
>> + }
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int amd_hfi_alloc_class_data(struct platform_device *pdev)
>> {
>> struct amd_hfi_cpuinfo *hfi_cpuinfo;
>> @@ -68,8 +206,7 @@ static int amd_hfi_alloc_class_data(struct platform_device *pdev)
>>
>> nr_class_id = cpuid_eax(AMD_HETERO_CPUID_27);
>> if (nr_class_id < 0 || nr_class_id > 255) {
>> - dev_warn(dev, "failed to get supported class number from CPUID %d\n",
>> - AMD_HETERO_CPUID_27);
>> + dev_warn(dev, "failed to get number of supported classes\n");
>
> This message was added in the previous patch and now immediately changed.
Will drop this change.
>
>> return -EINVAL;
>> }
>>
>> @@ -79,7 +216,10 @@ static int amd_hfi_alloc_class_data(struct platform_device *pdev)
>> sizeof(struct amd_hfi_classes), GFP_KERNEL);
>> if (!hfi_cpuinfo->amd_hfi_classes)
>> return -ENOMEM;
>> -
>> + hfi_cpuinfo->ipcc_scores = devm_kcalloc(dev, nr_class_id,
>> + sizeof(int), GFP_KERNEL);
>> + if (!hfi_cpuinfo->ipcc_scores)
>> + return -ENOMEM;
>> hfi_cpuinfo->nr_class = nr_class_id;
>> }
>>
>> @@ -93,6 +233,70 @@ static void amd_hfi_remove(struct platform_device *pdev)
>> mutex_destroy(&dev->lock);
>> }
>>
>> +static int amd_hfi_metadata_parser(struct platform_device *pdev,
>> + struct amd_hfi_data *amd_hfi_data)
>> +{
>> + struct acpi_pcct_ext_pcc_slave *pcct_ext;
>> + struct acpi_subtable_header *pcct_entry;
>> + struct mbox_chan *pcc_mbox_channels;
>> + struct acpi_table_header *pcct_tbl;
>> + struct pcc_mbox_chan *pcc_chan;
>> + acpi_status status;
>> + int ret;
>> +
>> + pcc_mbox_channels = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
>> + sizeof(*pcc_mbox_channels), GFP_KERNEL);
>> + if (!pcc_mbox_channels) {
>> + ret = -ENOMEM;
>> + goto out;
>
> Please return directly if there is nothing to rollback.
Ack
>
>> + }
>> +
>> + pcc_chan = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
>> + sizeof(*pcc_chan), GFP_KERNEL);
>> + if (!pcc_chan) {
>> + ret = -ENOMEM;
>> + goto out;
>
> Ditto.
>
>> + }
>> +
>> + status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
>> + if (ACPI_FAILURE(status) || !pcct_tbl) {
>> + ret = -ENODEV;
>> + goto out;
>
> Ditto.
>
>> + }
>> +
>> + /* get pointer to the first PCC subspace entry */
>> + pcct_entry = (struct acpi_subtable_header *) (
>> + (unsigned long)pcct_tbl + sizeof(struct acpi_table_pcct));
>> +
>> + pcc_chan->mchan = &pcc_mbox_channels[0];
>> +
>> + amd_hfi_data->pcc_chan = pcc_chan;
>> + amd_hfi_data->pcct_entry = pcct_entry;
>> + pcct_ext = (struct acpi_pcct_ext_pcc_slave *)pcct_entry;
>> +
>> + if (pcct_ext->length <= 0) {
>> + ret = -EINVAL;
>> + goto out;
>
> Ditto.
>
>> + }
>> +
>> + amd_hfi_data->shmem = devm_kmalloc(amd_hfi_data->dev, pcct_ext->length, GFP_KERNEL);
>
> Why kmalloc ?
>
>> + if (!amd_hfi_data->shmem) {
>> + ret = -ENOMEM;
>> + goto out;
>
> Return directly.
>
>> + }
>> +
>> + pcc_chan->shmem_base_addr = pcct_ext->base_address;
>> + pcc_chan->shmem_size = pcct_ext->length;
>> +
>> + /* parse the shared memory info from the pcct table */
>> + ret = amd_hfi_fill_metadata(amd_hfi_data);
>> +
>> + acpi_put_table(pcct_tbl);
>> +
>> +out:
>> + return ret;
>> +}
>> +
>> static const struct acpi_device_id amd_hfi_platform_match[] = {
>> { "AMDI0104", 0},
>> { }
>> @@ -121,6 +325,11 @@ static int amd_hfi_probe(struct platform_device *pdev)
>> if (ret)
>> goto out;
>
> This should do return ret; directly, not jump to out label which does
> nothing but return.
>
>>
>> + /* parse PCCT table */
>> + ret = amd_hfi_metadata_parser(pdev, amd_hfi_data);
>> + if (ret)
>> + goto out;
>> +
>> out:
>> return ret;
>
> Might again be there for churn avoidance, otherwise, please consider:
>
> return amd_hfi_metadata_parser(pdev, amd_hfi_data);
>
> That goto out should again just return ret directly.
>
>> }
>>
>
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