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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?vOc1W3mIJqrKIIinZ31TfQt9XeQFb8O5Xg9EfxKxhdUlcjvZUf+BhJxroDqN?= =?us-ascii?Q?oetCzhl9ycA/O4ILnNRjK4IKh94YbAKzyREdkmQWsrSvHuElRvmim7qu6Du+?= =?us-ascii?Q?HA95L15tPCIXV9hl4bIdbG/W2UzqJrOwf3Ou0TJA9g+42KuPmcVsRkW4WNv+?= =?us-ascii?Q?TQ/NwdjnQLqgLHq3TpHH2P7D5u2irTS9srNvPdhg+tugdI6UoeFGCBRj+b24?= =?us-ascii?Q?rd/3I5qQQKf4kmpilqP9WgVLBV4IdOG+h/i52jj+S8a4HGOJsOfjKk3Fpk+E?= =?us-ascii?Q?zzbtyrwKxOGzZWO0c5lZq/1IjSy+4Y1Ym4/dxk1K+jMEk78LHueLrumpZYy8?= =?us-ascii?Q?T50GpqWorsEPt8gJiGE0sncPTDDk/W4oUh1vubjDkK6wNfQoVY0an65To5s7?= =?us-ascii?Q?VgVGvTfkzhsK6+D5COPUVvSdywq+GRmfnQJs7Da5IDUx21wmBHiTHsWhLDMj?= =?us-ascii?Q?2sih4nLA8NfZoEOYiSB4/lKvEQzlIkgwc8rMY57/WJxQ4xpjyWFgGWPAp0hG?= =?us-ascii?Q?ebKDPvFG2aBD3z+eoyeeoYTwh1r3utcudY3IpmaRMysoom2i5vu0fAw6IcPt?= =?us-ascii?Q?2Q73gBR61QukGR44FI3/NT00+RmLm6rhZNyczru5+q2W6eIsJOqy/L2+edp8?= =?us-ascii?Q?nClNsJgbSJTyX9ge4qw95jOC0SUdDpp7Cc8BN8W6KaB1QGIj+Jlq9rZeWZX+?= =?us-ascii?Q?sM4CG3YrhwlmEgeRVMOt2e/gN3n2w4X+T9JCewDJWipwgzWKOBwlUCglewQ1?= =?us-ascii?Q?Wo611EYBOJ2CDTqovRRv11krm2X5nFkcE3gA6VUkJ4okSAfAWZCJs7Kby6gO?= =?us-ascii?Q?U74WYmdwrKSWSQziiPMlmnwKFuyLo9YUxOn2uY0roPo72AOwbD05JtdzDRIG?= =?us-ascii?Q?zKw4KiVEvaHUT5qhH7A0LF42LyLqzCpZLmzNd+tsC1eJCLR1T7jKnnoSNWtV?= =?us-ascii?Q?tXpgdUJupxn93G35NW35haXJhkQeowX7h3lduqDHDbraKCfspIy/2iusPAWa?= =?us-ascii?Q?A7LtZKp2236nx9CuN/A3pEsWX8x4I14w9p6pALXA5lZ+r1Hbx0N3O4IJMLP9?= =?us-ascii?Q?Cu58CQkZmAS6xu3Qa8LZgBh/pXi7X5E1VYhmwnupUjFsuIoy9EJ7OdU8g9t/?= =?us-ascii?Q?MFJuHTGrokI3Yw6kDMCC68s0hM30gPdoIZkwx9FFfbABKBPP7YUr+fgWW8Sg?= =?us-ascii?Q?3cvDU3pMgBeONSmPGZX0hGLIfFspAgKSx6A0flD4e+6hHF4COvf6P5F8bUvt?= =?us-ascii?Q?P/qipC0FbhZVV1L2kIroPjBuBEJTXNlmBgprCV0to8EPU+JG+yiDlZ/fIRyV?= =?us-ascii?Q?OFi+n/5UzMil0QktqZ/BH4rZX2ZA7Jby2F6ApQmZN/PGWe5ROT8qM5eP5apQ?= =?us-ascii?Q?ojIgPwuFQPBw4Xc1l+6NUBplIUn/+PhE4paig6Bgj7OOj/Q4q7CVjTMrYh2s?= =?us-ascii?Q?cqZ7hQkrjbmkQ9iBEYOZv8zbVfzJ4NMT633qaABb5oOxv935yoCpZdu0hhhF?= =?us-ascii?Q?+dH24wzSI9dEfVA0h6XA7TWEZUhV40388Q5RQWkCMDPlmQF4bC2iublAXsPd?= =?us-ascii?Q?gpRLIvWQp2zaTuQCvYInfAnR+P4bIp9JBvO5E4kyxTzCQMINztIQtpaRXhW/?= =?us-ascii?Q?nSIbZqtXy4iGnkgmGzItl624CaLiYbg3NET/MsK18DzSYYU8pWQK/1mgVvMG?= =?us-ascii?Q?XcPjgLLksE2A1k76UcBxzgOBvKY5fWztpF+l3i83G4tusLUQ85OfuY69eRzK?= =?us-ascii?Q?SRq0p5YvKg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 91aac00c-606f-4f73-f989-08dedd628958 X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB2370.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jul 2026 02:34:01.8535 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: s3UI7GSHgEnlO9aTefaYj/10EvRHzl6CYQ4hlnYE/axHfCrvxDKJFvbUu846mL26OSQd5NcogbPuLcU5Qoos+g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS5PPFDF2DDE6CD On Wed, Jul 08, 2026 at 11:35:55AM +0800, Alison Schofield wrote: > On Wed, Jul 08, 2026 at 06:40:23PM +0800, Richard Cheng wrote: > > The kernel now allows committed zero-size HDM decoders so BIOS can lock > > empty decoders; 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. > > At v5 review we chatted about a unit test for this. > Not sure what has happened since wrt the poison tail mappings, but > the check in cxl-topology.sh 'wants' to be in place to merge this. > > https://lore.kernel.org/linux-cxl/ajozhDmPogKi9hb5@MWDK4CY14F/ > > -- Alison > Hi Alison, Sorry I forgot about that, Just have the work sent out here. https://lore.kernel.org/linux-cxl/20260709022857.18732-1-icheng@nvidia.com/ Does this match what you expect ? --Richard > > > > > Signed-off-by: Vishal Aslot > > Signed-off-by: Richard Cheng > > --- > > Changelog: > > > > v6->v7: > > - Rebase onto cxl/for-7.3/cxl-type2-test. > > - Integrate mock_zero_size_decoders with special-topology parameter > > validation and reject its incompatible use with fail_autoassemble. > > > > 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 | 109 ++++++++++++++++++++++++++++++----- > > 1 file changed, 94 insertions(+), 15 deletions(-) > > > > diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c > > index 8ab2ce1262f3..fff2004a08c8 100644 > > --- a/tools/testing/cxl/test/cxl.c > > +++ b/tools/testing/cxl/test/cxl.c > > @@ -18,6 +18,7 @@ static int interleave_arithmetic; > > static bool extended_linear_cache; > > static bool fail_autoassemble; > > static bool type2_test; > > +static bool mock_zero_size_decoders; > > > > #define FAKE_QTG_ID 42 > > > > @@ -872,14 +873,13 @@ 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; > > } > > @@ -1072,16 +1072,49 @@ 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; > > } > > > > enum cxld_init_type { > > @@ -1114,7 +1147,7 @@ static enum cxld_init_type get_decoder_init_type(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)) > > return MOCK_DECODER_INIT_DEFAULT; > > > > return type2_test ? MOCK_DECODER_INIT_TYPE2_AUTO : > > @@ -1147,6 +1180,7 @@ static void mock_init_hdm_type2_cxled(struct cxl_endpoint_decoder *cxled, > > struct cxl_port *root_port; > > struct device *dev; > > u64 base; > > + int id = 0; > > > > base = window->base_hpa; > > cxld->hpa_range = (struct range) { > > @@ -1172,7 +1206,7 @@ static void mock_init_hdm_type2_cxled(struct cxl_endpoint_decoder *cxled, > > */ > > dport = port->parent_dport; > > root_port = dport->port; > > - dev = device_find_child(&root_port->dev, NULL, first_decoder); > > + dev = device_find_child(&root_port->dev, &id, match_decoder_by_index); > > /* > > * Ancestor ports are guaranteed to be enumerated before > > * @port, and all ports have at least one decoder. > > @@ -1232,6 +1266,20 @@ static void mock_init_hdm_type3_cxled(struct cxl_endpoint_decoder *cxled, > > 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; > > + } > > cxld->hpa_range = (struct range) { > > .start = base, > > .end = base + mock_auto_region_size - 1, > > @@ -1255,9 +1303,11 @@ static void mock_init_hdm_type3_cxled(struct cxl_endpoint_decoder *cxled, > > */ > > 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. > > @@ -1307,6 +1357,26 @@ static void mock_init_hdm_type3_cxled(struct cxl_endpoint_decoder *cxled, > > > > 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); > > + } > > } > > } > > > > @@ -2085,6 +2155,12 @@ static bool __init have_multiple_modparms(void) > > count++; > > if (type2_test) > > count++; > > + if (mock_zero_size_decoders) > > + count++; > > + > > + /* Zero-size decoders require decoder[0] to preserve commit order. */ > > + if (fail_autoassemble && mock_zero_size_decoders) > > + return true; > > > > return count > 1; > > } > > @@ -2493,6 +2569,9 @@ module_param(fail_autoassemble, bool, 0444); > > MODULE_PARM_DESC(fail_autoassemble, "Simulate missing member of an auto-region"); > > module_param(type2_test, bool, 0444); > > MODULE_PARM_DESC(type2_test, "Enable type 2 support testing"); > > +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 > >