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Date: Fri, 28 Jun 2024 11:51:36 -0700
From: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
To: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
daniel.sneddon@...ux.intel.com, tony.luck@...el.com,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
linux-perf-users@...r.kernel.org,
Josh Poimboeuf <jpoimboe@...nel.org>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>,
Andrew Cooper <andrew.cooper3@...rix.com>,
Brice Goglin <brice.goglin@...il.com>,
Mario Limonciello <mario.limonciello@....com>,
Perry Yuan <Perry.Yuan@....com>
Subject: Re: [PATCH v2 3/9] perf/x86/intel: Use topology_hw_cpu_type()
On Fri, Jun 28, 2024 at 04:59:18PM +0800, Mi, Dapeng wrote:
>
> On 6/28/2024 4:44 AM, Pawan Gupta wrote:
> > get_this_hybrid_cpu_type() misses a case when cpu-type is populated
> > regardless of X86_FEATURE_HYBRID_CPU. This is particularly true for hybrid
> > variants that have P or E cores fused off.
> >
> > Instead use topology_hw_cpu_type() as it does not rely on hybrid feature to
> > enumerate cpu-type. This can also help avoid the model-specific fixup
> > get_hybrid_cpu_type().
> >
> > Suggested-by: Dave Hansen <dave.hansen@...ux.intel.com>
> > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
> > ---
> > arch/x86/events/intel/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> > index 38c1b1f1deaa..0da1fd14b0ea 100644
> > --- a/arch/x86/events/intel/core.c
> > +++ b/arch/x86/events/intel/core.c
> > @@ -4753,7 +4753,7 @@ static void intel_pmu_check_hybrid_pmus(struct x86_hybrid_pmu *pmu)
> >
> > static struct x86_hybrid_pmu *find_hybrid_pmu_for_cpu(void)
> > {
> > - u8 cpu_type = get_this_hybrid_cpu_type();
> > + u8 cpu_type = topology_hw_cpu_type(smp_processor_id());
>
> As Kan said, ARL-H would have two different atom uarchs, so we have to use
> the extra native model id to identify them for PMU enabling. I'm not sure
> if we need a similar helper topology_hw_cpu_native_id(), it may depend on
> if the native id needs to be exposed to user space? such as whether there
> are different vulnerabilities between these two atom uarchs?
>
> For PMU enabling, we don't need to expose the native model ID to user
> space, so we define a new helper get_this_hybrid_cpu_native_id() and
> leverage it to identify the atom uarch.
As CPUID.1A.EAX returns both the native model ID and core type, we can
store it raw in topo->hw_cpu_type. Such that topo->hw_cpu_type contains
both the native model ID and core-type. Then use accessors to get them
separately?
As per Intel SDM Vol 2A, table 3-8, combination of core-type and native
model ID identifies the microarchitecture uniquely:
EAX Enumerates the native model ID and core type.
Bits 31-24: Core type*
10H: Reserved
20H: Intel Atom®
30H: Reserved
40H: Intel® Core™
Bits 23-00: Native model ID of the core. The core-type and native
model ID can be used to uniquely identify the microarchitecture of
the core.
Let me know if below patch that implements intel_get_native_model_id()
would work for your use case:
---
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 20e491c22b98..eaa84e4e4771 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -26,11 +26,13 @@ int mwait_usable(const struct cpuinfo_x86 *);
unsigned int x86_family(unsigned int sig);
unsigned int x86_model(unsigned int sig);
unsigned int x86_stepping(unsigned int sig);
+enum x86_hw_topo_cpu_type x86_get_hw_cpu_type(struct cpuinfo_x86 *c);
#ifdef CONFIG_CPU_SUP_INTEL
extern void __init sld_setup(struct cpuinfo_x86 *c);
extern bool handle_user_split_lock(struct pt_regs *regs, long error_code);
extern bool handle_guest_split_lock(unsigned long ip);
extern void handle_bus_lock(struct pt_regs *regs);
+u32 intel_get_native_model_id(struct cpuinfo_x86 *c);
#else
static inline void __init sld_setup(struct cpuinfo_x86 *c) {}
static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code)
@@ -44,6 +46,7 @@ static inline bool handle_guest_split_lock(unsigned long ip)
}
static inline void handle_bus_lock(struct pt_regs *regs) {}
+u32 intel_get_native_model_id(struct cpuinfo_x86 *c) { return 0; }
#endif
#ifdef CONFIG_IA32_FEAT_CTL
void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d8d715fcc25c..08794668750f 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -107,7 +107,7 @@ struct cpuinfo_topology {
u32 l2c_id;
// Hardware defined CPU-type
- u8 hw_cpu_type;
+ u32 hw_cpu_type;
};
struct cpuinfo_x86 {
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 717fdb928dc3..70f1a9661ce3 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -33,8 +33,6 @@
#include <linux/numa.h>
#include <linux/cpumask.h>
-#define X86_CPU_TYPE_INTEL_SHIFT 24
-
enum x86_hw_topo_cpu_type {
X86_HW_CPU_TYPE_UNKNOWN = 0,
X86_HW_CPU_TYPE_INTEL_ATOM = 0x20,
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 86e0c69a60f6..151c2377df21 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1292,6 +1292,11 @@ static bool __init cpu_matches(const struct x86_cpu_id *table, unsigned long whi
return m && !!(m->driver_data & which);
}
+enum x86_hw_topo_cpu_type __weak x86_get_hw_cpu_type(struct cpuinfo_x86 *c)
+{
+ return X86_HW_CPU_TYPE_UNKNOWN;
+}
+
u64 x86_read_arch_cap_msr(void)
{
u64 x86_arch_cap_msr = 0;
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index ac6c68a39051..3a951632d210 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1335,3 +1335,16 @@ void __init sld_setup(struct cpuinfo_x86 *c)
sld_state_setup();
sld_state_show();
}
+
+#define X86_INTEL_CPU_TYPE_SHIFT 24
+#define X86_INTEL_NATIVE_MODEL_ID_MASK ((1 << X86_INTEL_CPU_TYPE_SHIFT) - 1)
+
+enum x86_hw_topo_cpu_type x86_get_hw_cpu_type(struct cpuinfo_x86 *c)
+{
+ return c->topo.hw_cpu_type >> X86_INTEL_CPU_TYPE_SHIFT;
+}
+
+u32 intel_get_native_model_id(struct cpuinfo_x86 *c)
+{
+ return c->topo.hw_cpu_type & X86_INTEL_NATIVE_MODEL_ID_MASK;
+}
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 85ef17325c06..8493bcd4db0b 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <asm/cpu_device_id.h>
#include <asm/cpufeature.h>
+#include <asm/cpu.h>
#include <linux/cpu.h>
#include <linux/export.h>
#include <linux/slab.h>
@@ -22,7 +23,7 @@ static bool x86_match_hw_cpu_type(struct cpuinfo_x86 *c, const struct x86_cpu_id
if (boot_cpu_has(X86_FEATURE_HYBRID_CPU))
return true;
- return c->topo.hw_cpu_type == m->cpu_type;
+ return m->cpu_type == x86_get_hw_cpu_type(c);
}
/**
diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index 8b47bd6b0623..819f850b1960 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -87,6 +87,7 @@ static void parse_topology(struct topo_scan *tscan, bool early)
.cu_id = 0xff,
.llc_id = BAD_APICID,
.l2c_id = BAD_APICID,
+ .hw_cpu_type = X86_HW_CPU_TYPE_UNKNOWN,
};
struct cpuinfo_x86 *c = tscan->c;
struct {
@@ -132,6 +133,8 @@ static void parse_topology(struct topo_scan *tscan, bool early)
case X86_VENDOR_INTEL:
if (!IS_ENABLED(CONFIG_CPU_SUP_INTEL) || !cpu_parse_topology_ext(tscan))
parse_legacy(tscan);
+ if (c->cpuid_level >= 0x1a)
+ c->topo.hw_cpu_type = cpuid_eax(0x1a);
break;
case X86_VENDOR_HYGON:
if (IS_ENABLED(CONFIG_CPU_SUP_HYGON))
@@ -140,14 +143,6 @@ static void parse_topology(struct topo_scan *tscan, bool early)
}
}
-static void topo_set_hw_cpu_type(struct cpuinfo_x86 *c)
-{
- c->topo.hw_cpu_type = X86_HW_CPU_TYPE_UNKNOWN;
-
- if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 0x1a)
- c->topo.hw_cpu_type = cpuid_eax(0x1a) >> X86_CPU_TYPE_INTEL_SHIFT;
-}
-
static void topo_set_ids(struct topo_scan *tscan, bool early)
{
struct cpuinfo_x86 *c = tscan->c;
@@ -198,7 +193,6 @@ void cpu_parse_topology(struct cpuinfo_x86 *c)
}
topo_set_ids(&tscan, false);
- topo_set_hw_cpu_type(c);
}
void __init cpu_init_topology(struct cpuinfo_x86 *c)
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