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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-09-18 22:09:30 +02:00
Stanislav Kinsburskii
9365813cad
Add test_hmm coverage for the HMM lock-dropping fault path. The test module gets a new HMM_DMIRROR_READ_UNLOCKED ioctl that calls hmm_range_fault_unlocked_timeout() with a timeout of 0, exercising the unbounded retry mode while allowing the mmap lock to be dropped during fault handling. Add a userfaultfd_read selftest that registers an anonymous mapping with UFFDIO_REGISTER_MODE_MISSING, services the faults from a handler thread with UFFDIO_COPY, and verifies that HMM can read back the data supplied by the handler. This exercises the path where handle_mm_fault() drops mmap_lock and hmm_range_fault_unlocked_timeout() restarts the walk internally. Assisted-by: GitHub-Copilot:claude-opus-4.6 Link: https://lore.kernel.org/20260723-hmm-v10-v11-3-c55b003a4b61@gmail.com Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dave Airlie <airlied@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Dexuan Cui <decui@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Leon Romanovsky <leon@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lizhi Hou <lizhi.hou@amd.com> Cc: Long Li <longli@microsoft.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Lyude <lyude@redhat.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oded Gabbay <ogabbay@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Zimemrmann <tzimmermann@suse.de> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
82 lines
3.1 KiB
C
82 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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/*
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* This is a module to test the HMM (Heterogeneous Memory Management) API
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* of the kernel. It allows a userspace program to expose its entire address
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* space through the HMM test module device file.
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*/
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#ifndef _LIB_TEST_HMM_UAPI_H
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#define _LIB_TEST_HMM_UAPI_H
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#include <linux/types.h>
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#include <linux/ioctl.h>
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/*
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* Structure to pass to the HMM test driver to mimic a device accessing
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* system memory and ZONE_DEVICE private memory through device page tables.
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*
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* @addr: (in) user address the device will read/write
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* @ptr: (in) user address where device data is copied to/from
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* @npages: (in) number of pages to read/write
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* @cpages: (out) number of pages copied
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* @faults: (out) number of device page faults seen
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*/
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struct hmm_dmirror_cmd {
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__u64 addr;
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__u64 ptr;
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__u64 npages;
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__u64 cpages;
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__u64 faults;
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};
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/* Expose the address space of the calling process through hmm device file */
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#define HMM_DMIRROR_READ _IOWR('H', 0x00, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_MIGRATE_TO_DEV _IOWR('H', 0x02, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_MIGRATE_TO_SYS _IOWR('H', 0x03, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x04, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x06, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_RELEASE _IOWR('H', 0x07, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_FLAGS _IOWR('H', 0x08, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_READ_UNLOCKED _IOWR('H', 0x09, struct hmm_dmirror_cmd)
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#define HMM_DMIRROR_FLAG_FAIL_ALLOC (1ULL << 0)
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/*
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* Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT.
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* HMM_DMIRROR_PROT_ERROR: no valid mirror PTE for this page
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* HMM_DMIRROR_PROT_NONE: unpopulated PTE or PTE with no access
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* HMM_DMIRROR_PROT_READ: read-only PTE
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* HMM_DMIRROR_PROT_WRITE: read/write PTE
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* HMM_DMIRROR_PROT_PMD: PMD sized page is fully mapped by same permissions
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* HMM_DMIRROR_PROT_PUD: PUD sized page is fully mapped by same permissions
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* HMM_DMIRROR_PROT_ZERO: special read-only zero page
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* HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL: Migrated device private page on the
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* device the ioctl() is made
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* HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE: Migrated device private page on some
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* other device
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* HMM_DMIRROR_PROT_DEV_COHERENT: Migrate device coherent page on the device
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* the ioctl() is made
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*/
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enum {
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HMM_DMIRROR_PROT_ERROR = 0xFF,
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HMM_DMIRROR_PROT_NONE = 0x00,
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HMM_DMIRROR_PROT_READ = 0x01,
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HMM_DMIRROR_PROT_WRITE = 0x02,
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HMM_DMIRROR_PROT_PMD = 0x04,
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HMM_DMIRROR_PROT_PUD = 0x08,
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HMM_DMIRROR_PROT_ZERO = 0x10,
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HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL = 0x20,
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HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,
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HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL = 0x40,
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HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE = 0x50,
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};
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enum {
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/* 0 is reserved to catch uninitialized type fields */
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HMM_DMIRROR_MEMORY_DEVICE_PRIVATE = 1,
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HMM_DMIRROR_MEMORY_DEVICE_COHERENT,
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};
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#endif /* _LIB_TEST_HMM_UAPI_H */
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