On 19/11/2024 15:13, Carlo Nonato wrote:
>
>
> 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
>
> Signed-off-by: Carlo Nonato
> Signed-off-by: Marco Solieri
> ---
> v10:
> - moved CONFIG_NUMA check in arch/arm/Kconfig
> 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 | 78
> xen/arch/arm/setup.c | 3 ++
> xen/common/llc-coloring.c| 2 +-
> xen/include/xen/llc-coloring.h | 4 ++
> 9 files changed, 124 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 15b2e4a227..7f0712e674 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 if !NUMA
>
> 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
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -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
>
> +/*
