LLC coloring needs to know the last level cache layout in order to make the
best use of it. This can be probed by inspecting the CLIDR_EL1 register,
so the Last Level is defined as the last level visible by this register.
Note that this excludes system caches in some platforms.
Static memory allocation and cache coloring are incompatible because static
memory can't be guaranteed to use only colors assigned to the domain.
Panic during DomUs creation when both are enabled.
Based on original work from: Luca Miccio <lucmiccio@gmail.com>
Signed-off-by: Carlo Nonato <carlo.nonato@minervasys.tech>
Signed-off-by: Marco Solieri <marco.solieri@minervasys.tech>
---
v9:
- no changes
v8:
- no changes
v7:
- only minor changes
v6:
- get_llc_way_size() now checks for at least separate I/D caches
v5:
- used - instead of _ for filenames
- moved static-mem check in this patch
- moved dom0 colors parsing in next patch
- moved color allocation and configuration in next patch
- moved check_colors() in next patch
- colors are now printed in short form
v4:
- added "llc-coloring" cmdline option for the boot-time switch
- dom0 colors are now checked during domain init as for any other domain
- fixed processor.h masks bit width
- check for overflow in parse_color_config()
- check_colors() now checks also that colors are sorted and unique
---
docs/misc/cache-coloring.rst | 14 +++++
xen/arch/arm/Kconfig | 1 +
xen/arch/arm/Makefile | 1 +
xen/arch/arm/dom0less-build.c | 6 +++
xen/arch/arm/include/asm/processor.h | 16 ++++++
xen/arch/arm/llc-coloring.c | 77 ++++++++++++++++++++++++++++
xen/arch/arm/setup.c | 3 ++
xen/common/llc-coloring.c | 2 +-
xen/include/xen/llc-coloring.h | 4 ++
9 files changed, 123 insertions(+), 1 deletion(-)
create mode 100644 xen/arch/arm/llc-coloring.c
diff --git a/docs/misc/cache-coloring.rst b/docs/misc/cache-coloring.rst
index 0fe3830c40..b608284e9b 100644
--- a/docs/misc/cache-coloring.rst
+++ b/docs/misc/cache-coloring.rst
@@ -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.
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 323c967361..6fe6024efc 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -8,6 +8,7 @@ config ARM_64
depends on !ARM_32
select 64BIT
select HAS_FAST_MULTIPLY
+ select HAS_LLC_COLORING
config ARM
def_bool y
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index e4ad1ce851..ccbfc61f88 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -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
diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index f328a044e9..d93a85434e 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -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") )
{
diff --git a/xen/arch/arm/include/asm/processor.h b/xen/arch/arm/include/asm/processor.h
index 8e02410465..ef33ea198c 100644
--- a/xen/arch/arm/include/asm/processor.h
+++ b/xen/arch/arm/include/asm/processor.h
@@ -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
diff --git a/xen/arch/arm/llc-coloring.c b/xen/arch/arm/llc-coloring.c
new file mode 100644
index 0000000000..66c8db2baf
--- /dev/null
+++ b/xen/arch/arm/llc-coloring.c
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Last Level Cache (LLC) coloring support for ARM
+ *
+ * Copyright (C) 2022 Xilinx Inc.
+ */
+#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:
+ */
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 71ebaa77ca..84fecaabea 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -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();
diff --git a/xen/common/llc-coloring.c b/xen/common/llc-coloring.c
index 29d93875e0..3c98c86a56 100644
--- a/xen/common/llc-coloring.c
+++ b/xen/common/llc-coloring.c
@@ -10,7 +10,7 @@
#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;
diff --git a/xen/include/xen/llc-coloring.h b/xen/include/xen/llc-coloring.h
index c60c8050c5..67b27c995b 100644
--- a/xen/include/xen/llc-coloring.h
+++ b/xen/include/xen/llc-coloring.h
@@ -11,10 +11,14 @@
#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) {}
--
2.43.0