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cxl_test needs to exercise that path. Add a mock_zero_size_decoders module parameter (default off). When set, the special endpoints under host-bridge0 (cxl_mem.0 and cxl_mem.4) commit decoders 1 and 2 as zero-size + locked above the decoder[0] auto-region, mirrored on the parent switch and host bridge. The mocks take a real zero-size DPA reservation, like enumeration of real hardware, so commit_end lands on a zero-size decoder and the reservation, poison-by-endpoint, and teardown paths all run. Signed-off-by: Vishal Aslot Signed-off-by: Richard Cheng --- v5->v6: - Reword a mock comment, no functional change. v4->v5: - Mirror the v5 core semantics: mock zero-size decoders take a real zero-size DPA reservation via devm_cxl_dpa_reserve() so dpa_res/hdm_end/cxled->part match real hardware enumeration and the poison-by-endpoint walk reaches commit_end. - Set cxled->state = CXL_DECODER_STATE_AUTO to match init_hdm_decoder()'s fall-through (undoes the v2 switch to MANUAL). - cxld_registry_restore(): reserve unconditionally for enabled endpoint decoders; enabled now implies reserved, sized or not. v3->v4: - No change. v2->v3: - Gate the zero-size + locked decoder injection behind a new mock_zero_size_decoders module parameter (default off). v2 applied it unconditionally on the host-bridge0 auto-region endpoints, which the region test suite reuses, regressing 7 of 17 cxl unit tests; defaulting off leaves the shared topology untouched. v1->v2: - Replace second_decoder(), third_decoder() with a single match_decoder_by_index() helper, so all lookups share one matcher. - Use DEFINE_RANGE() for the empty range instead of an open-coded struct. - Set cxled->state = CXL_DECODER_STATE_MANUAL rather than STATE_AUTO. - Set CXL_DECODER_F_LOCK on the mock zero-size decoders to model the BIOS-burns-slots case. --- tools/testing/cxl/test/cxl.c | 100 ++++++++++++++++++++++++++++++----- 1 file changed, 86 insertions(+), 14 deletions(-) diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c index 418669927fb0..117691b3c62f 100644 --- a/tools/testing/cxl/test/cxl.c +++ b/tools/testing/cxl/test/cxl.c @@ -17,6 +17,7 @@ static int interleave_arithmetic; static bool extended_linear_cache; static bool fail_autoassemble; +static bool mock_zero_size_decoders; #define FAKE_QTG_ID 42 @@ -841,14 +842,13 @@ static int cxld_registry_restore(struct cxl_decoder *cxld, cxld_copy(cxld, &td->cxled.cxld); cxled->state = td->cxled.state; cxled->skip = td->cxled.skip; - if (range_len(&td->dpa_range)) { - rc = devm_cxl_dpa_reserve(cxled, td->dpa_range.start, - range_len(&td->dpa_range), - td->cxled.skip); - if (rc) { - init_disabled_mock_decoder(cxld); - return rc; - } + /* enabled endpoint decoders hold a reservation, sized or not */ + rc = devm_cxl_dpa_reserve(cxled, td->dpa_range.start, + range_len(&td->dpa_range), + td->cxled.skip); + if (rc) { + init_disabled_mock_decoder(cxld); + return rc; } port->commit_end = cxld->id; } @@ -1041,16 +1041,49 @@ static void default_mock_decoder(struct cxl_decoder *cxld) WARN_ON_ONCE(!cxld_registry_new(cxld)); } -static int first_decoder(struct device *dev, const void *data) +static int match_decoder_by_index(struct device *dev, const void *data) { + int target_id = *(const int *)data; struct cxl_decoder *cxld; if (!is_switch_decoder(dev)) return 0; cxld = to_cxl_decoder(dev); - if (cxld->id == 0) - return 1; - return 0; + return cxld->id == target_id; +} + +/* + * Mock a committed, locked, empty decoder + * (CXL r4.0 8.2.4.20.12). Gated by the mock_zero_size_decoders module + * param so the default cxl_test topology, shared by the region test + * suite, is left undisturbed. + */ +static void size_zero_mock_decoder_ep(struct cxl_decoder *cxld, u64 base) +{ + struct cxl_endpoint_decoder *cxled = to_cxl_endpoint_decoder(&cxld->dev); + + cxld->hpa_range = DEFINE_RANGE(base, base - 1); + cxld->interleave_ways = 2; + cxld->interleave_granularity = 4096; + cxld->target_type = CXL_DECODER_HOSTONLYMEM; + cxld->flags = CXL_DECODER_F_ENABLE | CXL_DECODER_F_LOCK; + cxled->state = CXL_DECODER_STATE_AUTO; + /* decoder[0] reserved [0, size/2), empty decoders sit at that watermark */ + devm_cxl_dpa_reserve(cxled, mock_auto_region_size / 2, 0, 0); + cxld->commit = mock_decoder_commit; + cxld->reset = mock_decoder_reset; +} + +static void size_zero_mock_decoder_sw(struct cxl_decoder *cxld, u64 base, + int level) +{ + cxld->flags = CXL_DECODER_F_ENABLE | CXL_DECODER_F_LOCK; + cxld->target_type = CXL_DECODER_HOSTONLYMEM; + cxld->interleave_ways = level == 0 ? 2 : 1; + cxld->interleave_granularity = 4096; + cxld->hpa_range = DEFINE_RANGE(base, base - 1); + cxld->commit = mock_decoder_commit; + cxld->reset = mock_decoder_reset; } /* @@ -1131,7 +1164,7 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld) * See 'cxl list -BMPu -m cxl_mem.0,cxl_mem.4' */ if (!is_endpoint_decoder(&cxld->dev) || !hb0 || pdev->id % 4 || - pdev->id > 4 || cxld->id > 0) { + pdev->id > 4 || cxld->id > (mock_zero_size_decoders ? 2 : 0)) { default_mock_decoder(cxld); return false; } @@ -1145,6 +1178,20 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld) base = window->base_hpa; if (extended_linear_cache) base += mock_auto_region_size; + + /* + * With mock_zero_size_decoders, decoders 1 and 2 of the special + * endpoints mock committed, locked, empty decoders above the + * decoder[0] auto-region (CXL r4.0 8.2.4.20.12). commit_end then + * points at a zero-size decoder, exercising the zero-size + * reservation and poison-by-endpoint code paths. + */ + if (cxld->id == 1 || cxld->id == 2) { + size_zero_mock_decoder_ep(cxld, base); + port->commit_end = cxld->id; + WARN_ON_ONCE(!cxld_registry_new(cxld)); + return false; + } cxld->hpa_range = (struct range) { .start = base, .end = base + mock_auto_region_size - 1, @@ -1168,9 +1215,11 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld) */ iter = port; for (i = 0; i < 2; i++) { + int id = 0; + dport = iter->parent_dport; iter = dport->port; - dev = device_find_child(&iter->dev, NULL, first_decoder); + dev = device_find_child(&iter->dev, &id, match_decoder_by_index); /* * Ancestor ports are guaranteed to be enumerated before * @port, and all ports have at least one decoder. @@ -1214,6 +1263,26 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld) cxld_registry_update(cxld); put_device(dev); + + if (!mock_zero_size_decoders) + continue; + + /* + * Mirror the endpoint: commit the next two switch decoders + * as zero-size + locked so the empty-decoder layout extends + * end-to-end through the switch and host bridge. + */ + for (id = 1; id <= 2; id++) { + dev = device_find_child(&iter->dev, &id, + match_decoder_by_index); + if (WARN_ON(!dev)) + continue; + cxld = to_cxl_decoder(dev); + size_zero_mock_decoder_sw(cxld, base, i); + iter->commit_end = id; + cxld_registry_update(cxld); + put_device(dev); + } } return false; @@ -2049,6 +2118,9 @@ module_param(extended_linear_cache, bool, 0444); MODULE_PARM_DESC(extended_linear_cache, "Enable extended linear cache support"); module_param(fail_autoassemble, bool, 0444); MODULE_PARM_DESC(fail_autoassemble, "Simulate missing member of an auto-region"); +module_param(mock_zero_size_decoders, bool, 0444); +MODULE_PARM_DESC(mock_zero_size_decoders, + "Mock committed, locked, empty decoders under host-bridge0"); module_init(cxl_test_init); module_exit(cxl_test_exit); MODULE_LICENSE("GPL v2"); -- 2.43.0