x86/resctrl: Enable non-contiguous CBMs in Intel CAT

The setting for non-contiguous 1s support in Intel CAT is
hardcoded to false. On these systems, writing non-contiguous
1s into the schemata file will fail before resctrl passes
the value to the hardware.

In Intel CAT CPUID.0x10.1:ECX[3] and CPUID.0x10.2:ECX[3] stopped
being reserved and now carry information about non-contiguous 1s
value support for L3 and L2 cache respectively. The CAT
capacity bitmask (CBM) supports a non-contiguous 1s value if
the bit is set.

The exception are Haswell systems where non-contiguous 1s value
support needs to stay disabled since they can't make use of CPUID
for Cache allocation.

Originally-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Peter Newman <peternewman@google.com>
Link: https://lore.kernel.org/r/1849b487256fe4de40b30f88450cba3d9abc9171.1696934091.git.maciej.wieczor-retman@intel.com

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index c09e4fdded3c73e0a9479ebc005fd6b530b794d7..19e0681f04356d6b184014003e23cc5cec3980f6 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -152,6 +152,7 @@ static inline void cache_alloc_hsw_probe(void)
        r->cache.cbm_len = 20;
        r->cache.shareable_bits = 0xc0000;
        r->cache.min_cbm_bits = 2;
+       r->cache.arch_has_sparse_bitmasks = false;
        r->alloc_capable = true;
 
        rdt_alloc_capable = true;
@@ -267,15 +268,18 @@ static void rdt_get_cache_alloc_cfg(int idx, struct rdt_resource *r)
 {
        struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
        union cpuid_0x10_1_eax eax;
+       union cpuid_0x10_x_ecx ecx;
        union cpuid_0x10_x_edx edx;
-       u32 ebx, ecx;
+       u32 ebx;
 
-       cpuid_count(0x00000010, idx, &eax.full, &ebx, &ecx, &edx.full);
+       cpuid_count(0x00000010, idx, &eax.full, &ebx, &ecx.full, &edx.full);
        hw_res->num_closid = edx.split.cos_max + 1;
        r->cache.cbm_len = eax.split.cbm_len + 1;
        r->default_ctrl = BIT_MASK(eax.split.cbm_len + 1) - 1;
        r->cache.shareable_bits = ebx & r->default_ctrl;
        r->data_width = (r->cache.cbm_len + 3) / 4;
+       if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+               r->cache.arch_has_sparse_bitmasks = ecx.split.noncont;
        r->alloc_capable = true;
 }
 
@@ -872,7 +876,6 @@ static __init void rdt_init_res_defs_intel(void)
 
                if (r->rid == RDT_RESOURCE_L3 ||
                    r->rid == RDT_RESOURCE_L2) {
-                       r->cache.arch_has_sparse_bitmasks = false;
                        r->cache.arch_has_per_cpu_cfg = false;
                        r->cache.min_cbm_bits = 1;
                } else if (r->rid == RDT_RESOURCE_MBA) {

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index ab45012288bb1ba1d5d34599b1b712216d16d580..beccb0e87ba7416651ca839c29e822dfd5542e78 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -87,10 +87,12 @@ int parse_bw(struct rdt_parse_data *data, struct resctrl_schema *s,
 
 /*
  * Check whether a cache bit mask is valid.
- * For Intel the SDM says:
- *     Please note that all (and only) contiguous '1' combinations
- *     are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
- * Additionally Haswell requires at least two bits set.
+ * On Intel CPUs, non-contiguous 1s value support is indicated by CPUID:
+ *   - CPUID.0x10.1:ECX[3]: L3 non-contiguous 1s value supported if 1
+ *   - CPUID.0x10.2:ECX[3]: L2 non-contiguous 1s value supported if 1
+ *
+ * Haswell does not support a non-contiguous 1s value and additionally
+ * requires at least two bits set.
  * AMD allows non-contiguous bitmasks.
  */
 static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 85ceaf9a31ac20099c86647b4958e4ca0f28fa6b..c47ef2f13e8e55ef74f55ece3a9a11fe50d46701 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -492,6 +492,15 @@ union cpuid_0x10_3_eax {
        unsigned int full;
 };
 
+/* CPUID.(EAX=10H, ECX=ResID).ECX */
+union cpuid_0x10_x_ecx {
+       struct {
+               unsigned int reserved:3;
+               unsigned int noncont:1;
+       } split;
+       unsigned int full;
+};
+
 /* CPUID.(EAX=10H, ECX=ResID).EDX */
 union cpuid_0x10_x_edx {
        struct {