@@ -111,6 +111,20 @@ Auto-probing of LLC specs
LLC size and number of ways are probed automatically by default.
+In the Arm implementation, this is done by inspecting the CLIDR_EL1 register.
+This means that other system caches that aren't visible there are ignored.
+
LLC specs can be manually set via the above command line parameters. This
bypasses any auto-probing and it's used to overcome failing situations, such as
flawed probing logic, or for debugging/testing purposes.
+
+Known issues and limitations
+****************************
+
+"xen,static-mem" isn't supported when coloring is enabled
+#########################################################
+
+In the domain configuration, "xen,static-mem" allows memory to be statically
+allocated to the domain. This isn't possible when LLC coloring is enabled,
+because that memory can't be guaranteed to use only colors assigned to the
+domain.
@@ -8,6 +8,7 @@ config ARM_64
depends on !ARM_32
select 64BIT
select HAS_FAST_MULTIPLY
+ select HAS_LLC_COLORING if !NUMA
config ARM
def_bool y
@@ -35,6 +35,7 @@ obj-$(CONFIG_IOREQ_SERVER) += ioreq.o
obj-y += irq.o
obj-y += kernel.init.o
obj-$(CONFIG_LIVEPATCH) += livepatch.o
+obj-$(CONFIG_LLC_COLORING) += llc-coloring.o
obj-$(CONFIG_MEM_ACCESS) += mem_access.o
obj-y += mm.o
obj-y += monitor.o
@@ -5,6 +5,7 @@
#include <xen/grant_table.h>
#include <xen/iocap.h>
#include <xen/libfdt/libfdt.h>
+#include <xen/llc-coloring.h>
#include <xen/sched.h>
#include <xen/serial.h>
#include <xen/sizes.h>
@@ -890,7 +891,12 @@ void __init create_domUs(void)
panic("No more domain IDs available\n");
if ( dt_find_property(node, "xen,static-mem", NULL) )
+ {
+ if ( llc_coloring_enabled )
+ panic("LLC coloring and static memory are incompatible\n");
+
flags |= CDF_staticmem;
+ }
if ( dt_property_read_bool(node, "direct-map") )
{
@@ -18,6 +18,22 @@
#define CTR_IDC_SHIFT 28
#define CTR_DIC_SHIFT 29
+/* CCSIDR Current Cache Size ID Register */
+#define CCSIDR_LINESIZE_MASK _AC(0x7, UL)
+#define CCSIDR_NUMSETS_SHIFT 13
+#define CCSIDR_NUMSETS_MASK _AC(0x3fff, UL)
+#define CCSIDR_NUMSETS_SHIFT_FEAT_CCIDX 32
+#define CCSIDR_NUMSETS_MASK_FEAT_CCIDX _AC(0xffffff, UL)
+
+/* CSSELR Cache Size Selection Register */
+#define CSSELR_LEVEL_MASK _AC(0x7, UL)
+#define CSSELR_LEVEL_SHIFT 1
+
+/* CLIDR Cache Level ID Register */
+#define CLIDR_CTYPEn_SHIFT(n) (3 * ((n) - 1))
+#define CLIDR_CTYPEn_MASK _AC(0x7, UL)
+#define CLIDR_CTYPEn_LEVELS 7
+
#define ICACHE_POLICY_VPIPT 0
#define ICACHE_POLICY_AIVIVT 1
#define ICACHE_POLICY_VIPT 2
new file mode 100644
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Last Level Cache (LLC) coloring support for ARM
+ *
+ * Copyright (C) 2024, Advanced Micro Devices, Inc.
+ * Copyright (C) 2024, Minerva Systems SRL
+ */
+#include <xen/llc-coloring.h>
+#include <xen/types.h>
+
+#include <asm/processor.h>
+#include <asm/sysregs.h>
+
+/* Return the LLC way size by probing the hardware */
+unsigned int __init get_llc_way_size(void)
+{
+ register_t ccsidr_el1;
+ register_t clidr_el1 = READ_SYSREG(CLIDR_EL1);
+ register_t csselr_el1 = READ_SYSREG(CSSELR_EL1);
+ register_t id_aa64mmfr2_el1 = READ_SYSREG(ID_AA64MMFR2_EL1);
+ uint32_t ccsidr_numsets_shift = CCSIDR_NUMSETS_SHIFT;
+ uint32_t ccsidr_numsets_mask = CCSIDR_NUMSETS_MASK;
+ unsigned int n, line_size, num_sets;
+
+ for ( n = CLIDR_CTYPEn_LEVELS; n != 0; n-- )
+ {
+ uint8_t ctype_n = (clidr_el1 >> CLIDR_CTYPEn_SHIFT(n)) &
+ CLIDR_CTYPEn_MASK;
+
+ /* Unified cache (see Arm ARM DDI 0487J.a D19.2.27) */
+ if ( ctype_n == 0b100 )
+ break;
+ }
+
+ if ( n == 0 )
+ return 0;
+
+ WRITE_SYSREG((n - 1) << CSSELR_LEVEL_SHIFT, CSSELR_EL1);
+ isb();
+
+ ccsidr_el1 = READ_SYSREG(CCSIDR_EL1);
+
+ /* Arm ARM: (Log2(Number of bytes in cache line)) - 4 */
+ line_size = 1U << ((ccsidr_el1 & CCSIDR_LINESIZE_MASK) + 4);
+
+ /* If FEAT_CCIDX is enabled, CCSIDR_EL1 has a different bit layout */
+ if ( (id_aa64mmfr2_el1 >> ID_AA64MMFR2_CCIDX_SHIFT) & 0x7 )
+ {
+ ccsidr_numsets_shift = CCSIDR_NUMSETS_SHIFT_FEAT_CCIDX;
+ ccsidr_numsets_mask = CCSIDR_NUMSETS_MASK_FEAT_CCIDX;
+ }
+
+ /* Arm ARM: (Number of sets in cache) - 1 */
+ num_sets = ((ccsidr_el1 >> ccsidr_numsets_shift) & ccsidr_numsets_mask) + 1;
+
+ printk(XENLOG_INFO "LLC found: L%u (line size: %u bytes, sets num: %u)\n",
+ n, line_size, num_sets);
+
+ /* Restore value in CSSELR_EL1 */
+ WRITE_SYSREG(csselr_el1, CSSELR_EL1);
+ isb();
+
+ return line_size * num_sets;
+}
+
+void __init arch_llc_coloring_init(void)
+{
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
@@ -12,6 +12,7 @@
#include <xen/device_tree.h>
#include <xen/domain_page.h>
#include <xen/grant_table.h>
+#include <xen/llc-coloring.h>
#include <xen/types.h>
#include <xen/string.h>
#include <xen/serial.h>
@@ -326,6 +327,8 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
printk("Command line: %s\n", cmdline);
cmdline_parse(cmdline);
+ llc_coloring_init();
+
setup_mm();
vm_init();
@@ -11,7 +11,7 @@
#define NR_LLC_COLORS (1U << CONFIG_LLC_COLORS_ORDER)
-static bool __ro_after_init llc_coloring_enabled;
+bool __ro_after_init llc_coloring_enabled;
boolean_param("llc-coloring", llc_coloring_enabled);
static unsigned int __initdata llc_size;
@@ -12,10 +12,14 @@
#include <public/domctl.h>
#ifdef CONFIG_LLC_COLORING
+extern bool llc_coloring_enabled;
+
void llc_coloring_init(void);
void dump_llc_coloring_info(void);
void domain_dump_llc_colors(const struct domain *d);
#else
+#define llc_coloring_enabled false
+
static inline void llc_coloring_init(void) {}
static inline void dump_llc_coloring_info(void) {}
static inline void domain_dump_llc_colors(const struct domain *d) {}