[PATCH v2 4/4] xen/cppc: introduce cppc data upload sub-hypercall

From: Penny Zheng
Date: Thu Dec 05 2024 - 00:44:07 EST

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As Xen is uncapable of parsing the ACPI dynamic table, this commit
introduces a new sub-hypercall XEN_PM_CPPC to deliver CPPC perf
caps data.

Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
---
drivers/acpi/cppc_acpi.c | 1 +
drivers/xen/xen-acpi-processor.c | 89 +++++++++++++++++++++++++++++++-
include/acpi/processor.h | 1 +
include/xen/interface/platform.h | 11 ++++
4 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 3a436591da07..3570a52a5dbd 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -860,6 +860,7 @@ static int acpi_cppc_processor_parse(struct acpi_processor *pr, struct cpc_desc
cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
}

+ pr->flags.has_cpc = 1;
pr_debug("Parsed _CPC entry for CPU: %d\n", pr->acpi_id);
kfree(output.pointer);
return 0;
diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index e9f38f171240..8a39e46c1ebc 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -25,6 +25,7 @@
#include <xen/xen.h>
#include <xen/interface/platform.h>
#include <asm/xen/hypercall.h>
+#include <acpi/cppc_acpi.h>

static int no_hypercall;
MODULE_PARM_DESC(off, "Inhibit the hypercall.");
@@ -45,8 +46,12 @@ static unsigned long *acpi_ids_done;
static unsigned long *acpi_id_present;
/* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
static unsigned long *acpi_id_cst_present;
+/* And if there is an _CPC entry for the ACPI IDs */
+static unsigned long *acpi_id_cpc_present;
/* Which ACPI P-State dependencies for a enumerated processor */
static struct acpi_psd_package *acpi_psd;
+/* ACPI CPPC structures for a enumerated processor */
+static struct cppc_perf_caps *acpi_cppc_data;

static bool pr_initialized;

@@ -208,6 +213,44 @@ static int xen_copy_pct_data(struct acpi_pct_register *pct,
dst_pct->address = pct->address;
return 0;
}
+static int push_cppc_to_hypervisor(struct acpi_processor *_pr)
+{
+ int ret = 0;
+ struct xen_platform_op op = {
+ .cmd = XENPF_set_processor_pminfo,
+ .interface_version = XENPF_INTERFACE_VERSION,
+ .u.set_pminfo.id = _pr->acpi_id,
+ .u.set_pminfo.type = XEN_PM_CPPC,
+ };
+ struct cppc_perf_caps *cppc_perf = acpi_cppc_data + _pr->acpi_id;
+
+ op.u.set_pminfo.cppc_data.highest_perf = cppc_perf->highest_perf;
+ op.u.set_pminfo.cppc_data.lowest_perf = cppc_perf->lowest_perf;
+ op.u.set_pminfo.cppc_data.nominal_perf = cppc_perf->nominal_perf;
+ op.u.set_pminfo.cppc_data.lowest_nonlinear_perf = cppc_perf->lowest_nonlinear_perf;
+ op.u.set_pminfo.cppc_data.lowest_freq = cppc_perf->lowest_freq;
+ op.u.set_pminfo.cppc_data.nominal_freq = cppc_perf->nominal_freq;
+
+ if (!no_hypercall)
+ ret = HYPERVISOR_platform_op(&op);
+
+ if (!ret) {
+ pr_debug("ACPI CPU%u - CPPC uploaded.\n", _pr->acpi_id);
+ pr_debug(" highest_perf: %d\n", cppc_perf->highest_perf);
+ pr_debug(" lowest_perf: %d\n", cppc_perf->lowest_perf);
+ pr_debug(" lowest_nonlinear_perf: %d\n", cppc_perf->lowest_nonlinear_perf);
+ pr_debug(" nominal_perf: %d\n", cppc_perf->nominal_perf);
+ pr_debug(" lowest_freq: %d Mhz\n", cppc_perf->lowest_freq);
+ pr_debug(" nominal_freq: %d Mhz\n", cppc_perf->nominal_freq);
+ } else if ((ret != -EINVAL) && (ret != -ENOSYS))
+ /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
+ * table is referencing a non-existing CPU - which can happen
+ * with broken ACPI tables. */
+ pr_warn("(_CPC): Hypervisor error (%d) for ACPI CPU%u\n",
+ ret, _pr->acpi_id);
+
+ return ret;
+}
static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
{
int ret = 0;
@@ -284,6 +327,9 @@ static int upload_pm_data(struct acpi_processor *_pr)
if (_pr->flags.power)
err = push_cxx_to_hypervisor(_pr);

+ if (_pr->flags.has_cpc)
+ err |= push_cppc_to_hypervisor(_pr);
+
if (_pr->performance && _pr->performance->states)
err |= push_pxx_to_hypervisor(_pr);

@@ -488,6 +534,7 @@ read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
union acpi_object object = { 0 };
struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
struct acpi_buffer cst_buf = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct acpi_buffer cpc_buf = { ACPI_ALLOCATE_BUFFER, NULL };
acpi_io_address pblk = 0;

status = acpi_get_type(handle, &acpi_type);
@@ -567,11 +614,20 @@ read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
/* .. and it has a C-state */
__set_bit(acpi_id, acpi_id_cst_present);

+ status = acpi_evaluate_object(handle, "_CPC", NULL, &cpc_buf);
+ if (ACPI_FAILURE(status)) {
+ return AE_OK;
+ }
+ kfree(cpc_buf.pointer);
+
+ /* .. and it has a _CPC entry */
+ __set_bit(acpi_id, acpi_id_cpc_present);
+
return AE_OK;
}
static int check_acpi_ids(struct acpi_processor *pr_backup)
{
- if (acpi_id_present && acpi_id_cst_present)
+ if (acpi_id_present && acpi_id_cst_present && acpi_id_cpc_present)
/* OK, done this once .. skip to uploading */
goto upload;

@@ -588,11 +644,19 @@ static int check_acpi_ids(struct acpi_processor *pr_backup)
return -ENOMEM;
}

+ acpi_id_cpc_present = bitmap_zalloc(nr_acpi_bits, GFP_KERNEL);
+ if (!acpi_id_cpc_present) {
+ bitmap_free(acpi_id_present);
+ bitmap_free(acpi_id_cst_present);
+ return -ENOMEM;
+ }
+
acpi_psd = kcalloc(nr_acpi_bits, sizeof(struct acpi_psd_package),
GFP_KERNEL);
if (!acpi_psd) {
bitmap_free(acpi_id_present);
bitmap_free(acpi_id_cst_present);
+ bitmap_free(acpi_id_cpc_present);
return -ENOMEM;
}

@@ -608,6 +672,12 @@ static int check_acpi_ids(struct acpi_processor *pr_backup)
pr_backup->acpi_id = i;
/* Mask out C-states if there are no _CST or PBLK */
pr_backup->flags.power = test_bit(i, acpi_id_cst_present);
+ /* Mask out relevant flag if there are no _CPC */
+ pr_backup->flags.has_cpc = test_bit(i, acpi_id_cpc_present);
+ if (pr_backup->flags.has_cpc) {
+ if (xen_processor_get_perf_caps(pr_backup, acpi_cppc_data + i))
+ return -EINVAL;
+ }
/* num_entries is non-zero if we evaluated _PSD */
if (acpi_psd[i].num_entries) {
memcpy(&pr_backup->performance->domain_info,
@@ -726,6 +796,15 @@ static int __init xen_acpi_processor_init(void)
bitmap_free(acpi_ids_done);
return -ENOMEM;
}
+
+ acpi_cppc_data = kcalloc(nr_acpi_bits, sizeof(struct cppc_perf_caps),
+ GFP_KERNEL);
+ if (!acpi_cppc_data) {
+ pr_debug("Memory allocation error for acpi_cppc_data\n");
+ rc = -ENOMEM;
+ goto err1_out;
+ }
+
for_each_possible_cpu(i) {
if (!zalloc_cpumask_var_node(
&per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
@@ -751,6 +830,11 @@ static int __init xen_acpi_processor_init(void)
rc = acpi_processor_get_performance_info(pr);
if (rc)
goto err_out;
+
+ pr->flags.pcc_unsupported = true;
+ rc = xen_processor_get_perf_caps(pr, acpi_cppc_data + i);
+ if (rc)
+ goto err_out;
}

rc = xen_upload_processor_pm_data();
@@ -766,6 +850,8 @@ static int __init xen_acpi_processor_init(void)

err_out:
/* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
+ kfree(acpi_cppc_data);
+err1_out:
free_acpi_perf_data();
bitmap_free(acpi_ids_done);
return rc;
@@ -779,6 +865,7 @@ static void __exit xen_acpi_processor_exit(void)
bitmap_free(acpi_id_present);
bitmap_free(acpi_id_cst_present);
kfree(acpi_psd);
+ kfree(acpi_cppc_data);
for_each_possible_cpu(i)
acpi_processor_unregister_performance(i);

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 18499cc11366..66492f5d68a8 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -214,6 +214,7 @@ struct acpi_processor_flags {
u8 bm_control:1;
u8 bm_check:1;
u8 has_cst:1;
+ u8 has_cpc:1;
u8 pcc_unsupported:1;
u8 has_lpi:1;
u8 power_setup_done:1;
diff --git a/include/xen/interface/platform.h b/include/xen/interface/platform.h
index 79a443c65ea9..e11bb9443dc0 100644
--- a/include/xen/interface/platform.h
+++ b/include/xen/interface/platform.h
@@ -319,6 +319,7 @@ DEFINE_GUEST_HANDLE_STRUCT(xenpf_getidletime_t);
#define XEN_PM_PX 1
#define XEN_PM_TX 2
#define XEN_PM_PDC 3
+#define XEN_PM_CPPC 4
/* Px sub info type */
#define XEN_PX_PCT 1
#define XEN_PX_PSS 2
@@ -384,6 +385,15 @@ struct xen_processor_px {
};
DEFINE_GUEST_HANDLE_STRUCT(xen_processor_px);

+struct xen_processor_cppc {
+ uint32_t highest_perf;
+ uint32_t nominal_perf;
+ uint32_t lowest_perf;
+ uint32_t lowest_nonlinear_perf;
+ uint32_t lowest_freq;
+ uint32_t nominal_freq;
+};
+
struct xen_psd_package {
uint64_t num_entries;
uint64_t revision;
@@ -412,6 +422,7 @@ struct xenpf_set_processor_pminfo {
struct xen_processor_power power;/* Cx: _CST/_CSD */
struct xen_processor_performance perf; /* Px: _PPC/_PCT/_PSS/_PSD */
GUEST_HANDLE(uint32_t) pdc;
+ struct xen_processor_cppc cppc_data; /* _CPC */
};
};
DEFINE_GUEST_HANDLE_STRUCT(xenpf_set_processor_pminfo);
--
2.34.1

Next message: Raghavendra K T: "Re: [RFC PATCH] resource: Fix CXL node not populated issue"
Previous message: Penny Zheng: "[PATCH v2 3/4] xen/cppc: get xen-required cppc perf caps data"
In reply to: Jason Andryuk: "Re: [PATCH v2 3/4] xen/cppc: get xen-required cppc perf caps data"
Next in thread: Jason Andryuk: "Re: [PATCH v2 4/4] xen/cppc: introduce cppc data upload sub-hypercall"
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