In the !x86_match_cpu() fallback path, has_generic_discovery_table()
is removed because it does not handle multiple PCI devices. Instead,
use PCI_ANY_ID in generic_uncore_init[] to probe all PCI devices.
For MSR portals, only probe MSR 0x201e to keep the fallback simple, as
this path is best-effort only.
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
V2: Separate patch from [PATCH V1 1/7]
- Move has_generic_discovery_table() related code to its own patch for
easier review.
arch/x86/events/intel/uncore.c | 3 ++
arch/x86/events/intel/uncore_discovery.c | 42 +++++-------------------
2 files changed, 12 insertions(+), 33 deletions(-)
diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 844030ef87c4..2a1c6dce8a35 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1835,6 +1835,9 @@ static const struct uncore_plat_init generic_uncore_init __initconst = {
.cpu_init = intel_uncore_generic_uncore_cpu_init,
.pci_init = intel_uncore_generic_uncore_pci_init,
.mmio_init = intel_uncore_generic_uncore_mmio_init,
+ .domain[0].base_is_pci = true,
+ .domain[0].discovery_base = PCI_ANY_ID,
+ .domain[1].discovery_base = UNCORE_DISCOVERY_MSR,
};
static const struct x86_cpu_id intel_uncore_match[] __initconst = {
diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 3bcbf974d3a8..6f409e0b4722 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -12,24 +12,6 @@
static struct rb_root discovery_tables = RB_ROOT;
static int num_discovered_types[UNCORE_ACCESS_MAX];
-static bool has_generic_discovery_table(void)
-{
- struct pci_dev *dev;
- int dvsec;
-
- dev = pci_get_device(PCI_VENDOR_ID_INTEL, UNCORE_DISCOVERY_TABLE_DEVICE, NULL);
- if (!dev)
- return false;
-
- /* A discovery table device has the unique capability ID. */
- dvsec = pci_find_next_ext_capability(dev, 0, UNCORE_EXT_CAP_ID_DISCOVERY);
- pci_dev_put(dev);
- if (dvsec)
- return true;
-
- return false;
-}
-
static int logical_die_id;
static int get_device_die_id(struct pci_dev *dev)
@@ -358,12 +340,7 @@ static bool uncore_discovery_pci(struct uncore_discovery_domain *domain)
struct pci_dev *dev = NULL;
bool parsed = false;
- if (domain->discovery_base)
- device = domain->discovery_base;
- else if (has_generic_discovery_table())
- device = UNCORE_DISCOVERY_TABLE_DEVICE;
- else
- device = PCI_ANY_ID;
+ device = domain->discovery_base;
/*
* Start a new search and iterates through the list of
@@ -406,7 +383,7 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
{
unsigned long *die_mask;
bool parsed = false;
- int cpu, die, msr;
+ int cpu, die;
u64 base;
die_mask = kcalloc(BITS_TO_LONGS(uncore_max_dies()),
@@ -414,16 +391,13 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
if (!die_mask)
return false;
- msr = domain->discovery_base ?
- domain->discovery_base : UNCORE_DISCOVERY_MSR;
-
cpus_read_lock();
for_each_online_cpu(cpu) {
die = topology_logical_die_id(cpu);
if (__test_and_set_bit(die, die_mask))
continue;
- if (rdmsrq_safe_on_cpu(cpu, msr, &base))
+ if (rdmsrq_safe_on_cpu(cpu, domain->discovery_base, &base))
continue;
if (!base)
@@ -446,10 +420,12 @@ bool uncore_discovery(struct uncore_plat_init *init)
for (i = 0; i < UNCORE_DISCOVERY_DOMAINS; i++) {
domain = &init->domain[i];
- if (!domain->base_is_pci)
- ret |= uncore_discovery_msr(domain);
- else
- ret |= uncore_discovery_pci(domain);
+ if (domain->discovery_base) {
+ if (!domain->base_is_pci)
+ ret |= uncore_discovery_msr(domain);
+ else
+ ret |= uncore_discovery_pci(domain);
+ }
}
return ret;
--
2.52.0
On 1/1/2026 6:42 AM, Zide Chen wrote:
> In the !x86_match_cpu() fallback path, has_generic_discovery_table()
> is removed because it does not handle multiple PCI devices. Instead,
> use PCI_ANY_ID in generic_uncore_init[] to probe all PCI devices.
>
> For MSR portals, only probe MSR 0x201e to keep the fallback simple, as
> this path is best-effort only.
>
> Signed-off-by: Zide Chen <zide.chen@intel.com>
> ---
> V2: Separate patch from [PATCH V1 1/7]
> - Move has_generic_discovery_table() related code to its own patch for
> easier review.
>
> arch/x86/events/intel/uncore.c | 3 ++
> arch/x86/events/intel/uncore_discovery.c | 42 +++++-------------------
> 2 files changed, 12 insertions(+), 33 deletions(-)
>
> diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
> index 844030ef87c4..2a1c6dce8a35 100644
> --- a/arch/x86/events/intel/uncore.c
> +++ b/arch/x86/events/intel/uncore.c
> @@ -1835,6 +1835,9 @@ static const struct uncore_plat_init generic_uncore_init __initconst = {
> .cpu_init = intel_uncore_generic_uncore_cpu_init,
> .pci_init = intel_uncore_generic_uncore_pci_init,
> .mmio_init = intel_uncore_generic_uncore_mmio_init,
> + .domain[0].base_is_pci = true,
> + .domain[0].discovery_base = PCI_ANY_ID,
> + .domain[1].discovery_base = UNCORE_DISCOVERY_MSR,
> };
>
> static const struct x86_cpu_id intel_uncore_match[] __initconst = {
> diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
> index 3bcbf974d3a8..6f409e0b4722 100644
> --- a/arch/x86/events/intel/uncore_discovery.c
> +++ b/arch/x86/events/intel/uncore_discovery.c
> @@ -12,24 +12,6 @@
> static struct rb_root discovery_tables = RB_ROOT;
> static int num_discovered_types[UNCORE_ACCESS_MAX];
>
> -static bool has_generic_discovery_table(void)
> -{
> - struct pci_dev *dev;
> - int dvsec;
> -
> - dev = pci_get_device(PCI_VENDOR_ID_INTEL, UNCORE_DISCOVERY_TABLE_DEVICE, NULL);
> - if (!dev)
> - return false;
> -
> - /* A discovery table device has the unique capability ID. */
> - dvsec = pci_find_next_ext_capability(dev, 0, UNCORE_EXT_CAP_ID_DISCOVERY);
> - pci_dev_put(dev);
> - if (dvsec)
> - return true;
> -
> - return false;
> -}
> -
> static int logical_die_id;
>
> static int get_device_die_id(struct pci_dev *dev)
> @@ -358,12 +340,7 @@ static bool uncore_discovery_pci(struct uncore_discovery_domain *domain)
> struct pci_dev *dev = NULL;
> bool parsed = false;
>
> - if (domain->discovery_base)
> - device = domain->discovery_base;
> - else if (has_generic_discovery_table())
> - device = UNCORE_DISCOVERY_TABLE_DEVICE;
> - else
> - device = PCI_ANY_ID;
> + device = domain->discovery_base;
>
> /*
> * Start a new search and iterates through the list of
> @@ -406,7 +383,7 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
> {
> unsigned long *die_mask;
> bool parsed = false;
> - int cpu, die, msr;
> + int cpu, die;
> u64 base;
>
> die_mask = kcalloc(BITS_TO_LONGS(uncore_max_dies()),
> @@ -414,16 +391,13 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
> if (!die_mask)
> return false;
>
> - msr = domain->discovery_base ?
> - domain->discovery_base : UNCORE_DISCOVERY_MSR;
> -
> cpus_read_lock();
> for_each_online_cpu(cpu) {
> die = topology_logical_die_id(cpu);
> if (__test_and_set_bit(die, die_mask))
> continue;
>
> - if (rdmsrq_safe_on_cpu(cpu, msr, &base))
> + if (rdmsrq_safe_on_cpu(cpu, domain->discovery_base, &base))
> continue;
>
> if (!base)
> @@ -446,10 +420,12 @@ bool uncore_discovery(struct uncore_plat_init *init)
>
> for (i = 0; i < UNCORE_DISCOVERY_DOMAINS; i++) {
> domain = &init->domain[i];
> - if (!domain->base_is_pci)
> - ret |= uncore_discovery_msr(domain);
> - else
> - ret |= uncore_discovery_pci(domain);
> + if (domain->discovery_base) {
> + if (!domain->base_is_pci)
> + ret |= uncore_discovery_msr(domain);
> + else
> + ret |= uncore_discovery_pci(domain);
> + }
> }
>
> return ret;
LGTM.
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 1897336728b4ab0229fb73bb6f1e94cfe914afa9
Gitweb: https://git.kernel.org/tip/1897336728b4ab0229fb73bb6f1e94cfe914afa9
Author: Zide Chen <zide.chen@intel.com>
AuthorDate: Wed, 31 Dec 2025 14:42:20 -08:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 06 Jan 2026 16:34:23 +01:00
perf/x86/intel/uncore: Remove has_generic_discovery_table()
In the !x86_match_cpu() fallback path, has_generic_discovery_table()
is removed because it does not handle multiple PCI devices. Instead,
use PCI_ANY_ID in generic_uncore_init[] to probe all PCI devices.
For MSR portals, only probe MSR 0x201e to keep the fallback simple, as
this path is best-effort only.
Signed-off-by: Zide Chen <zide.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://patch.msgid.link/20251231224233.113839-4-zide.chen@intel.com
---
arch/x86/events/intel/uncore.c | 3 ++-
arch/x86/events/intel/uncore_discovery.c | 42 ++++-------------------
2 files changed, 12 insertions(+), 33 deletions(-)
diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 78a03af..2387b1a 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1835,6 +1835,9 @@ static const struct uncore_plat_init generic_uncore_init __initconst = {
.cpu_init = intel_uncore_generic_uncore_cpu_init,
.pci_init = intel_uncore_generic_uncore_pci_init,
.mmio_init = intel_uncore_generic_uncore_mmio_init,
+ .domain[0].base_is_pci = true,
+ .domain[0].discovery_base = PCI_ANY_ID,
+ .domain[1].discovery_base = UNCORE_DISCOVERY_MSR,
};
static const struct x86_cpu_id intel_uncore_match[] __initconst = {
diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 25b6a65..aaa0810 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -12,24 +12,6 @@
static struct rb_root discovery_tables = RB_ROOT;
static int num_discovered_types[UNCORE_ACCESS_MAX];
-static bool has_generic_discovery_table(void)
-{
- struct pci_dev *dev;
- int dvsec;
-
- dev = pci_get_device(PCI_VENDOR_ID_INTEL, UNCORE_DISCOVERY_TABLE_DEVICE, NULL);
- if (!dev)
- return false;
-
- /* A discovery table device has the unique capability ID. */
- dvsec = pci_find_next_ext_capability(dev, 0, UNCORE_EXT_CAP_ID_DISCOVERY);
- pci_dev_put(dev);
- if (dvsec)
- return true;
-
- return false;
-}
-
static int logical_die_id;
static int get_device_die_id(struct pci_dev *dev)
@@ -358,12 +340,7 @@ static bool uncore_discovery_pci(struct uncore_discovery_domain *domain)
struct pci_dev *dev = NULL;
bool parsed = false;
- if (domain->discovery_base)
- device = domain->discovery_base;
- else if (has_generic_discovery_table())
- device = UNCORE_DISCOVERY_TABLE_DEVICE;
- else
- device = PCI_ANY_ID;
+ device = domain->discovery_base;
/*
* Start a new search and iterates through the list of
@@ -406,7 +383,7 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
{
unsigned long *die_mask;
bool parsed = false;
- int cpu, die, msr;
+ int cpu, die;
u64 base;
die_mask = kcalloc(BITS_TO_LONGS(uncore_max_dies()),
@@ -414,16 +391,13 @@ static bool uncore_discovery_msr(struct uncore_discovery_domain *domain)
if (!die_mask)
return false;
- msr = domain->discovery_base ?
- domain->discovery_base : UNCORE_DISCOVERY_MSR;
-
cpus_read_lock();
for_each_online_cpu(cpu) {
die = topology_logical_die_id(cpu);
if (__test_and_set_bit(die, die_mask))
continue;
- if (rdmsrq_safe_on_cpu(cpu, msr, &base))
+ if (rdmsrq_safe_on_cpu(cpu, domain->discovery_base, &base))
continue;
if (!base)
@@ -446,10 +420,12 @@ bool uncore_discovery(struct uncore_plat_init *init)
for (i = 0; i < UNCORE_DISCOVERY_DOMAINS; i++) {
domain = &init->domain[i];
- if (!domain->base_is_pci)
- ret |= uncore_discovery_msr(domain);
- else
- ret |= uncore_discovery_pci(domain);
+ if (domain->discovery_base) {
+ if (!domain->base_is_pci)
+ ret |= uncore_discovery_msr(domain);
+ else
+ ret |= uncore_discovery_pci(domain);
+ }
}
return ret;© 2016 - 2026 Red Hat, Inc.