From 4fe516d2ad1a6b827694db134fa2a0af97917b41 Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Tue, 14 Oct 2025 01:24:31 -0700 Subject: [PATCH] cxl/acpi: Make the XOR calculations available for testing In preparation for adding a test module that can exercise the address translation functions performed by the CXL Driver, refactor the XOR implementation like this: - Extract the core calculation into a standalone helper function, - Export the new function for use by test module cxl_translate only, - Enhance the parameter validation since this new function will be called from a test module with no guarantee of valid parameters, - Move the define of struct cxl_cxims_data to cxl.h so the test module can build xormaps. Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Signed-off-by: Alison Schofield Signed-off-by: Dave Jiang --- drivers/cxl/acpi.c | 41 ++++++++++++++++++++++++++++++----------- drivers/cxl/cxl.h | 13 +++++++++++++ 2 files changed, 43 insertions(+), 11 deletions(-) diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index bd2e282ca93a..a8069278cb56 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -11,25 +11,36 @@ #include "cxlpci.h" #include "cxl.h" -struct cxl_cxims_data { - int nr_maps; - u64 xormaps[] __counted_by(nr_maps); -}; - static const guid_t acpi_cxl_qtg_id_guid = GUID_INIT(0xF365F9A6, 0xA7DE, 0x4071, 0xA6, 0x6A, 0xB4, 0x0C, 0x0B, 0x4F, 0x8E, 0x52); -static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr) +#define HBIW_TO_NR_MAPS_SIZE (CXL_DECODER_MAX_INTERLEAVE + 1) +static const int hbiw_to_nr_maps[HBIW_TO_NR_MAPS_SIZE] = { + [1] = 0, [2] = 1, [3] = 0, [4] = 2, [6] = 1, [8] = 3, [12] = 2, [16] = 4 +}; + +static const int valid_hbiw[] = { 1, 2, 3, 4, 6, 8, 12, 16 }; + +u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw) { - struct cxl_cxims_data *cximsd = cxlrd->platform_data; - int hbiw = cxlrd->cxlsd.nr_targets; + int nr_maps_to_apply = -1; u64 val; int pos; - /* No xormaps for host bridge interleave ways of 1 or 3 */ - if (hbiw == 1 || hbiw == 3) - return addr; + /* + * Strictly validate hbiw since this function is used for testing and + * that nullifies any expectation of trusted parameters from the CXL + * Region Driver. + */ + for (int i = 0; i < ARRAY_SIZE(valid_hbiw); i++) { + if (valid_hbiw[i] == hbiw) { + nr_maps_to_apply = hbiw_to_nr_maps[hbiw]; + break; + } + } + if (nr_maps_to_apply == -1 || nr_maps_to_apply > cximsd->nr_maps) + return ULLONG_MAX; /* * In regions using XOR interleave arithmetic the CXL HPA may not @@ -60,6 +71,14 @@ static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr) return addr; } +EXPORT_SYMBOL_FOR_MODULES(cxl_do_xormap_calc, "cxl_translate"); + +static u64 cxl_apply_xor_maps(struct cxl_root_decoder *cxlrd, u64 addr) +{ + struct cxl_cxims_data *cximsd = cxlrd->platform_data; + + return cxl_do_xormap_calc(cximsd, addr, cxlrd->cxlsd.nr_targets); +} struct cxl_cxims_context { struct device *dev; diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 10bee9aaa943..e8931b626fc6 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -743,6 +743,19 @@ int cxl_validate_translation_params(u8 eiw, u16 eig, int pos); u64 cxl_calculate_hpa_offset(u64 dpa_offset, int pos, u8 eiw, u16 eig); u64 cxl_calculate_dpa_offset(u64 hpa_offset, u8 eiw, u16 eig); int cxl_calculate_position(u64 hpa_offset, u8 eiw, u16 eig); +struct cxl_cxims_data { + int nr_maps; + u64 xormaps[] __counted_by(nr_maps); +}; + +#if IS_ENABLED(CONFIG_CXL_ACPI) +u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw); +#else +static inline u64 cxl_do_xormap_calc(struct cxl_cxims_data *cximsd, u64 addr, int hbiw) +{ + return ULLONG_MAX; +} +#endif int cxl_num_decoders_committed(struct cxl_port *port); bool is_cxl_port(const struct device *dev);