June 2024 - Linux-kselftest-mirror

[RFC PATCH 00/11] New KVM ioctl to link a gmem inode to a new gmem file

by Ackerley Tng

Hello, This patchset builds upon the code at https://lore.kernel.org/lkml/20230718234512.1690985-1-seanjc@google.com/T/. This code is available at https://github.com/googleprodkernel/linux-cc/tree/kvm-gmem-link-migrate-rfc…. In guest_mem v11, a split file/inode model was proposed, where memslot bindings belong to the file and pages belong to the inode. This model lends itself well to having different VMs use separate files pointing to the same inode. This RFC proposes an ioctl, KVM_LINK_GUEST_MEMFD, that takes a VM and a gmem fd, and returns another gmem fd referencing a different file and associated with VM. This RFC also includes an update to KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM to migrate memory context (slot->arch.lpage_info and kvm->mem_attr_array) from source to destination vm, intra-host. Intended usage of the two ioctls: 1. Source VM’s fd is passed to destination VM via unix sockets 2. Destination VM uses new ioctl KVM_LINK_GUEST_MEMFD to link source VM’s fd to a new fd. 3. Destination VM will pass new fds to KVM_SET_USER_MEMORY_REGION, which will bind the new file, pointing to the same inode that the source VM’s file points to, to memslots 4. Use KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM to move kvm->mem_attr_array and slot->arch.lpage_info to the destination VM. 5. Run the destination VM as per normal Some other approaches considered were: + Using the linkat() syscall, but that requires a mount/directory for a source fd to be linked to + Using the dup() syscall, but that only duplicates the fd, and both fds point to the same file --- Ackerley Tng (11): KVM: guest_mem: Refactor out kvm_gmem_alloc_file() KVM: guest_mem: Add ioctl KVM_LINK_GUEST_MEMFD KVM: selftests: Add tests for KVM_LINK_GUEST_MEMFD ioctl KVM: selftests: Test transferring private memory to another VM KVM: x86: Refactor sev's flag migration_in_progress to kvm struct KVM: x86: Refactor common code out of sev.c KVM: x86: Refactor common migration preparation code out of sev_vm_move_enc_context_from KVM: x86: Let moving encryption context be configurable KVM: x86: Handle moving of memory context for intra-host migration KVM: selftests: Generalize migration functions from sev_migrate_tests.c KVM: selftests: Add tests for migration of private mem arch/x86/include/asm/kvm_host.h | 4 +- arch/x86/kvm/svm/sev.c | 85 ++----- arch/x86/kvm/svm/svm.h | 3 +- arch/x86/kvm/x86.c | 221 +++++++++++++++++- arch/x86/kvm/x86.h | 6 + include/linux/kvm_host.h | 18 ++ include/uapi/linux/kvm.h | 8 + tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 42 ++++ .../selftests/kvm/include/kvm_util_base.h | 31 +++ .../kvm/x86_64/private_mem_migrate_tests.c | 93 ++++++++ .../selftests/kvm/x86_64/sev_migrate_tests.c | 48 ++-- virt/kvm/guest_mem.c | 151 ++++++++++-- virt/kvm/kvm_main.c | 10 + virt/kvm/kvm_mm.h | 7 + 15 files changed, 596 insertions(+), 132 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_migrate_tests.c -- 2.41.0.640.ga95def55d0-goog

2 weeks, 3 days

3
15
0 0

[PATCH v6 0/5] userfaultfd move option

by Suren Baghdasaryan

This patch series introduces UFFDIO_MOVE feature to userfaultfd, which has long been implemented and maintained by Andrea in his local tree [1], but was not upstreamed due to lack of use cases where this approach would be better than allocating a new page and copying the contents. Previous upstraming attempts could be found at [6] and [7]. UFFDIO_COPY performs ~20% better than UFFDIO_MOVE when the application needs pages to be allocated [2]. However, with UFFDIO_MOVE, if pages are available (in userspace) for recycling, as is usually the case in heap compaction algorithms, then we can avoid the page allocation and memcpy (done by UFFDIO_COPY). Also, since the pages are recycled in the userspace, we avoid the need to release (via madvise) the pages back to the kernel [3]. We see over 40% reduction (on a Google pixel 6 device) in the compacting thread’s completion time by using UFFDIO_MOVE vs. UFFDIO_COPY. This was measured using a benchmark that emulates a heap compaction implementation using userfaultfd (to allow concurrent accesses by application threads). More details of the usecase are explained in [3]. Furthermore, UFFDIO_MOVE enables moving swapped-out pages without touching them within the same vma. Today, it can only be done by mremap, however it forces splitting the vma. TODOs for follow-up improvements: - cross-mm support. Known differences from single-mm and missing pieces: - memcg recharging (might need to isolate pages in the process) - mm counters - cross-mm deposit table moves - cross-mm test - document the address space where src and dest reside in struct uffdio_move - TLB flush batching. Will require extensive changes to PTL locking in move_pages_pte(). OTOH that might let us reuse parts of mremap code. Changes since v5 [10]: - added logic to split large folios in move_pages_pte(), per David Hildenbrand - added check for PAE before split_huge_pmd() to avoid the split if the move operation can't be done - replaced calls to default_huge_page_size() with read_pmd_pagesize() in uffd_move_pmd test, per David Hildenbrand - fixed the condition in uffd_move_test_common() checking if area alignment is needed Changes since v4 [9]: - added Acked-by in patch 1, per Peter Xu - added description for ctx, mm and mode parameters of move_pages(), per kernel test robot - added Reviewed-by's, per Peter Xu and Axel Rasmussen - removed unused operations in uffd_test_case_ops - refactored uffd-unit-test changes to avoid using global variables and handle pmd moves without page size overrides, per Peter Xu Changes since v3 [8]: - changed retry path in folio_lock_anon_vma_read() to unlock and then relock RCU, per Peter Xu - removed cross-mm support from initial patchset, per David Hildenbrand - replaced BUG_ONs with VM_WARN_ON or WARN_ON_ONCE, per David Hildenbrand - added missing cache flushing, per Lokesh Gidra and Peter Xu - updated manpage text in the patch description, per Peter Xu - renamed internal functions from "remap" to "move", per Peter Xu - added mmap_changing check after taking mmap_lock, per Peter Xu - changed uffd context check to ensure dst_mm is registered onto uffd we are operating on, Peter Xu and David Hildenbrand - changed to non-maybe variants of maybe*_mkwrite(), per David Hildenbrand - fixed warning for CONFIG_TRANSPARENT_HUGEPAGE=n, per kernel test robot - comments cleanup, per David Hildenbrand and Peter Xu - checks for VM_IO,VM_PFNMAP,VM_HUGETLB,..., per David Hildenbrand - prevent moving pinned pages, per Peter Xu - changed uffd tests to call move uffd_test_ctx_clear() at the end of the test run instead of in the beginning of the next run - added support for testcase-specific ops - added test for moving PMD-aligned blocks Changes since v2 [5]: - renamed UFFDIO_REMAP to UFFDIO_MOVE, per David Hildenbrand - rebase over mm-unstable to use folio_move_anon_rmap(), per David Hildenbrand - added text for manpage explaining DONTFORK and KSM requirements for this feature, per David Hildenbrand - check for anon_vma changes in the fast path of folio_lock_anon_vma_read, per Peter Xu - updated the title and description of the first patch, per David Hildenbrand - updating comments in folio_lock_anon_vma_read() explaining the need for anon_vma checks, per David Hildenbrand - changed all mapcount checks to PageAnonExclusive, per Jann Horn and David Hildenbrand - changed counters in remap_swap_pte() from MM_ANONPAGES to MM_SWAPENTS, per Jann Horn - added a check for PTE change after folio is locked in remap_pages_pte(), per Jann Horn - added handling of PMD migration entries and bailout when pmd_devmap(), per Jann Horn - added checks to ensure both src and dst VMAs are writable, per Peter Xu - added UFFD_FEATURE_MOVE, per Peter Xu - removed obsolete comments, per Peter Xu - renamed remap_anon_pte to remap_present_pte, per Peter Xu - added a comment for folio_get_anon_vma() explaining the need for anon_vma checks, per Peter Xu - changed error handling in remap_pages() to make it more clear, per Peter Xu - changed EFAULT to EAGAIN to retry when a hugepage appears or disappears from under us, per Peter Xu - added links to previous upstreaming attempts, per David Hildenbrand Changes since v1 [4]: - add mmget_not_zero in userfaultfd_remap, per Jann Horn - removed extern from function definitions, per Matthew Wilcox - converted to folios in remap_pages_huge_pmd, per Matthew Wilcox - use PageAnonExclusive in remap_pages_huge_pmd, per David Hildenbrand - handle pgtable transfers between MMs, per Jann Horn - ignore concurrent A/D pte bit changes, per Jann Horn - split functions into smaller units, per David Hildenbrand - test for folio_test_large in remap_anon_pte, per Matthew Wilcox - use pte_swp_exclusive for swapcount check, per David Hildenbrand - eliminated use of mmu_notifier_invalidate_range_start_nonblock, per Jann Horn - simplified THP alignment checks, per Jann Horn - refactored the loop inside remap_pages, per Jann Horn - additional clarifying comments, per Jann Horn Main changes since Andrea's last version [1]: - Trivial translations from page to folio, mmap_sem to mmap_lock - Replace pmd_trans_unstable() with pte_offset_map_nolock() and handle its possible failure - Move pte mapping into remap_pages_pte to allow for retries when source page or anon_vma is contended. Since pte_offset_map_nolock() start RCU read section, we can't block anymore after mapping a pte, so have to unmap the ptesm do the locking and retry. - Add and use anon_vma_trylock_write() to avoid blocking while in RCU read section. - Accommodate changes in mmu_notifier_range_init() API, switch to mmu_notifier_invalidate_range_start_nonblock() to avoid blocking while in RCU read section. - Open-code now removed __swp_swapcount() - Replace pmd_read_atomic() with pmdp_get_lockless() - Add new selftest for UFFDIO_MOVE [1] https://gitlab.com/aarcange/aa/-/commit/2aec7aea56b10438a3881a20a411aa4b1fc… [2] https://lore.kernel.org/all/1425575884-2574-1-git-send-email-aarcange@redha… [3] https://lore.kernel.org/linux-mm/CA+EESO4uO84SSnBhArH4HvLNhaUQ5nZKNKXqxRCyj… [4] https://lore.kernel.org/all/20230914152620.2743033-1-surenb@google.com/ [5] https://lore.kernel.org/all/20230923013148.1390521-1-surenb@google.com/ [6] https://lore.kernel.org/all/1425575884-2574-21-git-send-email-aarcange@redh… [7] https://lore.kernel.org/all/cover.1547251023.git.blake.caldwell@colorado.ed… [8] https://lore.kernel.org/all/20231009064230.2952396-1-surenb@google.com/ [9] https://lore.kernel.org/all/20231028003819.652322-1-surenb@google.com/ [10] https://lore.kernel.org/all/20231121171643.3719880-1-surenb@google.com/ Andrea Arcangeli (2): mm/rmap: support move to different root anon_vma in folio_move_anon_rmap() userfaultfd: UFFDIO_MOVE uABI Suren Baghdasaryan (3): selftests/mm: call uffd_test_ctx_clear at the end of the test selftests/mm: add uffd_test_case_ops to allow test case-specific operations selftests/mm: add UFFDIO_MOVE ioctl test Documentation/admin-guide/mm/userfaultfd.rst | 3 + fs/userfaultfd.c | 72 +++ include/linux/rmap.h | 5 + include/linux/userfaultfd_k.h | 11 + include/uapi/linux/userfaultfd.h | 29 +- mm/huge_memory.c | 122 ++++ mm/khugepaged.c | 3 + mm/rmap.c | 30 + mm/userfaultfd.c | 614 +++++++++++++++++++ tools/testing/selftests/mm/uffd-common.c | 39 +- tools/testing/selftests/mm/uffd-common.h | 9 + tools/testing/selftests/mm/uffd-stress.c | 5 +- tools/testing/selftests/mm/uffd-unit-tests.c | 192 ++++++ 13 files changed, 1130 insertions(+), 4 deletions(-) -- 2.43.0.rc2.451.g8631bc7472-goog

1 month

7
43
0 0

[PATCH v2 0/6] cleanups, fixes, and progress towards avoiding "make headers"

by John Hubbard

Jeff Xu, I apologize for this churn: I was forced to drop your Reviewed-by and Tested-by tags from 2 of the 3 mseal patches, because the __NR_mseal fix is completely different now. Changes since v1: a) Reworked the mseal fix to use the kernel's in-tree unistd*.h files, instead of hacking in a __NR_mseal definition directly. (Thanks to David Hildenbrand for pointing out that this needed to be done.) b) Fixed the subject line of the kvm and mdwe patch. c) Reordered the patches so as to group the mseal changes together. d) ADDED an additional patch, 6/6, to remove various __NR_xx items and checks from the mm selftests. Cover letter, updated for v2: Eventually, once the build succeeds on a sufficiently old distro, the idea is to delete $(KHDR_INCLUDES) from the selftests/mm build, and then after that, from selftests/lib.mk and all of the other selftest builds. For now, this series merely achieves a clean build of selftests/mm on a not-so-old distro: Ubuntu 23.04. In other words, after this series is applied, it is possible to delete $(KHDR_INCLUDES) from selftests/mm/Makefile and the build will still succeed. 1. Add tools/uapi/asm/unistd_[32|x32|64].h files, which include definitions of __NR_mseal, and include them (indirectly) from the files that use __NR_mseal. The new files are copied from ./usr/include/asm, which is how we have agreed to do this sort of thing, see [1]. 2. Add fs.h, similarly created: it was copied directly from a snapshot of ./usr/include/linux/fs.h after running "make headers". 3. Add a few selected prctl.h values that the ksm and mdwe tests require. 4. Factor out some common code from mseal_test.c and seal_elf.c, into a new mseal_helpers.h file. 5. Remove local __NR_* definitions and checks. [1] commit e076eaca5906 ("selftests: break the dependency upon local header files") John Hubbard (6): selftests/mm: mseal, self_elf: fix missing __NR_mseal selftests/mm: mseal, self_elf: factor out test macros and other duplicated items selftests/mm: mseal, self_elf: rename TEST_END_CHECK to REPORT_TEST_PASS selftests/mm: fix vm_util.c build failures: add snapshot of fs.h selftests/mm: kvm, mdwe fixes to avoid requiring "make headers" selftests/mm: remove local __NR_* definitions tools/include/uapi/asm/unistd_32.h | 458 ++++++++++++++++++ tools/include/uapi/asm/unistd_64.h | 380 +++++++++++++++ tools/include/uapi/asm/unistd_x32.h | 369 ++++++++++++++ tools/include/uapi/linux/fs.h | 392 +++++++++++++++ tools/testing/selftests/mm/hugepage-mremap.c | 2 +- .../selftests/mm/ksm_functional_tests.c | 8 +- tools/testing/selftests/mm/mdwe_test.c | 1 + tools/testing/selftests/mm/memfd_secret.c | 14 +- tools/testing/selftests/mm/mkdirty.c | 8 +- tools/testing/selftests/mm/mlock2.h | 1 + tools/testing/selftests/mm/mrelease_test.c | 2 +- tools/testing/selftests/mm/mseal_helpers.h | 41 ++ tools/testing/selftests/mm/mseal_test.c | 143 ++---- tools/testing/selftests/mm/pagemap_ioctl.c | 2 +- tools/testing/selftests/mm/protection_keys.c | 2 +- tools/testing/selftests/mm/seal_elf.c | 37 +- tools/testing/selftests/mm/uffd-common.c | 4 - tools/testing/selftests/mm/uffd-stress.c | 16 +- tools/testing/selftests/mm/uffd-unit-tests.c | 14 +- tools/testing/selftests/mm/vm_util.h | 15 + 20 files changed, 1717 insertions(+), 192 deletions(-) create mode 100644 tools/include/uapi/asm/unistd_32.h create mode 100644 tools/include/uapi/asm/unistd_64.h create mode 100644 tools/include/uapi/asm/unistd_x32.h create mode 100644 tools/include/uapi/linux/fs.h create mode 100644 tools/testing/selftests/mm/mseal_helpers.h base-commit: 2ccbdf43d5e758f8493a95252073cf9078a5fea5 -- 2.45.2

3 months, 1 week

4
22
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[PATCH 0/5] riscv: add support for Zaamo and Zalrsc extensions

by Clément Léger

Since commit e87412e621f1 ("integrate Zaamo and Zalrsc text (#1304)"), the A extension has been described as a set of instructions provided by Zaamo and Zalrsc. Add these two extensions. This series is based on the Zc one [1]. Link: https://lore.kernel.org/linux-riscv/20240619113529.676940-1-cleger@rivosinc… --- Clément Léger (5): dt-bindings: riscv: add Zaamo and Zalrsc ISA extension description riscv: add parsing for Zaamo and Zalrsc extensions riscv: hwprobe: export Zaamo and Zalrsc extensions RISC-V: KVM: Allow Zaamo/Zalrsc extensions for Guest/VM KVM: riscv: selftests: Add Zaamo/Zalrsc extensions to get-reg-list test Documentation/arch/riscv/hwprobe.rst | 8 ++++++++ .../devicetree/bindings/riscv/extensions.yaml | 19 +++++++++++++++++++ arch/riscv/include/asm/hwcap.h | 2 ++ arch/riscv/include/uapi/asm/hwprobe.h | 2 ++ arch/riscv/include/uapi/asm/kvm.h | 2 ++ arch/riscv/kernel/cpufeature.c | 9 ++++++++- arch/riscv/kernel/sys_hwprobe.c | 2 ++ arch/riscv/kvm/vcpu_onereg.c | 4 ++++ .../selftests/kvm/riscv/get-reg-list.c | 8 ++++++++ 9 files changed, 55 insertions(+), 1 deletion(-) -- 2.45.2

5 months

4
11
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[PATCH v4] memfd: `MFD_NOEXEC_SEAL` should not imply `MFD_ALLOW_SEALING`

by Barnabás Pőcze

`MFD_NOEXEC_SEAL` should remove the executable bits and set `F_SEAL_EXEC` to prevent further modifications to the executable bits as per the comment in the uapi header file: not executable and sealed to prevent changing to executable However, commit 105ff5339f498a ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC") that introduced this feature made it so that `MFD_NOEXEC_SEAL` unsets `F_SEAL_SEAL`, essentially acting as a superset of `MFD_ALLOW_SEALING`. Nothing implies that it should be so, and indeed up until the second version of the of the patchset[0] that introduced `MFD_EXEC` and `MFD_NOEXEC_SEAL`, `F_SEAL_SEAL` was not removed, however, it was changed in the third revision of the patchset[1] without a clear explanation. This behaviour is surprising for application developers, there is no documentation that would reveal that `MFD_NOEXEC_SEAL` has the additional effect of `MFD_ALLOW_SEALING`. Additionally, combined with `vm.memfd_noexec=2` it has the effect of making all memfds initially sealable. So do not remove `F_SEAL_SEAL` when `MFD_NOEXEC_SEAL` is requested, thereby returning to the pre-Linux 6.3 behaviour of only allowing sealing when `MFD_ALLOW_SEALING` is specified. Now, this is technically a uapi break. However, the damage is expected to be minimal. To trigger user visible change, a program has to do the following steps: - create memfd: - with `MFD_NOEXEC_SEAL`, - without `MFD_ALLOW_SEALING`; - try to add seals / check the seals. But that seems unlikely to happen intentionally since this change essentially reverts the kernel's behaviour to that of Linux <6.3, so if a program worked correctly on those older kernels, it will likely work correctly after this change. I have used Debian Code Search and GitHub to try to find potential breakages, and I could only find a single one. dbus-broker's memfd_create() wrapper is aware of this implicit `MFD_ALLOW_SEALING` behaviour, and tries to work around it[2]. This workaround will break. Luckily, this only affects the test suite, it does not affect the normal operations of dbus-broker. There is a PR with a fix[3]. I also carried out a smoke test by building a kernel with this change and booting an Arch Linux system into GNOME and Plasma sessions. There was also a previous attempt to address this peculiarity by introducing a new flag[4]. [0]: https://lore.kernel.org/lkml/20220805222126.142525-3-jeffxu@google.com/ [1]: https://lore.kernel.org/lkml/20221202013404.163143-3-jeffxu@google.com/ [2]: https://github.com/bus1/dbus-broker/blob/9eb0b7e5826fc76cad7b025bc46f267d4a… [3]: https://github.com/bus1/dbus-broker/pull/366 [4]: https://lore.kernel.org/lkml/20230714114753.170814-1-david@readahead.eu/ Cc: stable(a)vger.kernel.org Signed-off-by: Barnabás Pőcze <pobrn(a)protonmail.com> --- * v3: https://lore.kernel.org/linux-mm/20240611231409.3899809-1-jeffxu@chromium.o… * v2: https://lore.kernel.org/linux-mm/20240524033933.135049-1-jeffxu@google.com/ * v1: https://lore.kernel.org/linux-mm/20240513191544.94754-1-pobrn@protonmail.co… This fourth version returns to removing the inconsistency as opposed to documenting its existence, with the same code change as v1 but with a somewhat extended commit message. This is sent because I believe it is worth at least a try; it can be easily reverted if bigger application breakages are discovered than initially imagined. --- mm/memfd.c | 9 ++++----- tools/testing/selftests/memfd/memfd_test.c | 2 +- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index 7d8d3ab3fa37..8b7f6afee21d 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -356,12 +356,11 @@ SYSCALL_DEFINE2(memfd_create, inode->i_mode &= ~0111; file_seals = memfd_file_seals_ptr(file); - if (file_seals) { - *file_seals &= ~F_SEAL_SEAL; + if (file_seals) *file_seals |= F_SEAL_EXEC; - } - } else if (flags & MFD_ALLOW_SEALING) { - /* MFD_EXEC and MFD_ALLOW_SEALING are set */ + } + + if (flags & MFD_ALLOW_SEALING) { file_seals = memfd_file_seals_ptr(file); if (file_seals) *file_seals &= ~F_SEAL_SEAL; diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 95af2d78fd31..7b78329f65b6 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -1151,7 +1151,7 @@ static void test_noexec_seal(void) mfd_def_size, MFD_CLOEXEC | MFD_NOEXEC_SEAL); mfd_assert_mode(fd, 0666); - mfd_assert_has_seals(fd, F_SEAL_EXEC); + mfd_assert_has_seals(fd, F_SEAL_SEAL | F_SEAL_EXEC); mfd_fail_chmod(fd, 0777); close(fd); } -- 2.45.2

5 months, 2 weeks

4
5
0 0

[PATCH v3 0/5] Add support for the Idle HLT intercept feature

by Manali Shukla

The upcoming new Idle HLT Intercept feature allows for the HLT instruction execution by a vCPU to be intercepted by the hypervisor only if there are no pending V_INTR and V_NMI events for the vCPU. When the vCPU is expected to service the pending V_INTR and V_NMI events, the Idle HLT intercept won’t trigger. The feature allows the hypervisor to determine if the vCPU is actually idle and reduces wasteful VMEXITs. Presence of the Idle HLT Intercept feature is indicated via CPUID function Fn8000_000A_EDX[30]. Document for the Idle HLT intercept feature is available at [1]. [1]: AMD64 Architecture Programmer's Manual Pub. 24593, April 2024, Vol 2, 15.9 Instruction Intercepts (Table 15-7: IDLE_HLT). https://bugzilla.kernel.org/attachment.cgi?id=306250 Testing Done: - Added a selftest to test the Idle HLT intercept functionality. - Compile and functionality testing for the Idle HLT intercept selftest are only done for x86_64. - Tested SEV and SEV-ES guest for the Idle HLT intercept functionality. v2 -> v3 - Incorporated Andrew's suggestion to structure vcpu_stat_types in a way that each architecture can share the generic types and also provide its own. v1 -> v2 - Done changes in svm_idle_hlt_test based on the review comments from Sean. - Added an enum based approach to get binary stats in vcpu_get_stat() which doesn't use string to get stat data based on the comments from Sean. - Added self_halt() and cli() helpers based on the comments from Sean. Manali Shukla (5): x86/cpufeatures: Add CPUID feature bit for Idle HLT intercept KVM: SVM: Add Idle HLT intercept support KVM: selftests: Add safe_halt() and cli() helpers to common code KVM: selftests: Add an interface to read the data of named vcpu stat KVM: selftests: KVM: SVM: Add Idle HLT intercept test arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/svm.h | 1 + arch/x86/include/uapi/asm/svm.h | 2 + arch/x86/kvm/svm/svm.c | 11 ++- tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/include/kvm_util.h | 44 +++++++++ .../kvm/include/x86_64/kvm_util_arch.h | 40 +++++++++ .../selftests/kvm/include/x86_64/processor.h | 18 ++++ tools/testing/selftests/kvm/lib/kvm_util.c | 32 +++++++ .../selftests/kvm/x86_64/svm_idle_hlt_test.c | 89 +++++++++++++++++++ 10 files changed, 236 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/svm_idle_hlt_test.c base-commit: d91a9cc16417b8247213a0144a1f0fd61dc855dd -- 2.34.1

7 months

5
20
0 0

[PATCH 0/2] selftest: rtc: Add rtc feature detection and rtc file check

by Joseph Jang

1. In order to make rtctest more explicit and robust, we propose to use RTC_PARAM_GET ioctl interface to check rtc alarm feature state before running alarm related tests. 2. The rtctest requires the read permission on /dev/rtc0. The rtctest will be skipped if the /dev/rtc0 is not readable. Joseph Jang (2): selftest: rtc: Add to check rtc alarm status for alarm related test selftest: rtc: Check if could access /dev/rtc0 before testing tools/testing/selftests/rtc/Makefile | 2 +- tools/testing/selftests/rtc/rtctest.c | 71 ++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 2 deletions(-) -- 2.34.1

7 months, 1 week

3
15
0 0

[PATCH v2 00/25] Enable FRED with KVM VMX

by Xin Li

This patch set enables the Intel flexible return and event delivery (FRED) architecture with KVM VMX to allow guests to utilize FRED. The FRED architecture defines simple new transitions that change privilege level (ring transitions). The FRED architecture was designed with the following goals: 1) Improve overall performance and response time by replacing event delivery through the interrupt descriptor table (IDT event delivery) and event return by the IRET instruction with lower latency transitions. 2) Improve software robustness by ensuring that event delivery establishes the full supervisor context and that event return establishes the full user context. The new transitions defined by the FRED architecture are FRED event delivery and, for returning from events, two FRED return instructions. FRED event delivery can effect a transition from ring 3 to ring 0, but it is used also to deliver events incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to ring 3, while the other (ERETS) returns while remaining in ring 0. Collectively, FRED event delivery and the FRED return instructions are FRED transitions. Intel VMX architecture is extended to run FRED guests, and the major changes are: 1) New VMCS fields for FRED context management, which includes two new event data VMCS fields, eight new guest FRED context VMCS fields and eight new host FRED context VMCS fields. 2) VMX nested-exception support for proper virtualization of stack levels introduced with FRED architecture. Search for the latest FRED spec in most search engines with this search pattern: site:intel.com FRED (flexible return and event delivery) specification As the native FRED patches are committed in the tip tree "x86/fred" branch: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/?h=x86/fred, and we have received a good amount of review comments for v1, it's time to send out v2 based on this branch for further help from the community. Patch 1-2 are cleanups to VMX basic and misc MSRs, which were sent out earlier as a preparation for FRED changes: https://lore.kernel.org/kvm/20240206182032.1596-1-xin3.li@intel.com/T/#u Patch 3-15 add FRED support to VMX. Patch 16-21 add FRED support to nested VMX. Patch 22 exposes FRED and its baseline features to KVM guests. Patch 23-25 add FRED selftests. There is also a counterpart qemu patch set for FRED at: https://lore.kernel.org/qemu-devel/20231109072012.8078-1-xin3.li@intel.com/…, which works with this patch set to allow KVM to run FRED guests. Changes since v1: * Always load the secondary VM exit controls (Sean Christopherson). * Remove FRED VM entry/exit controls consistency checks in setup_vmcs_config() (Sean Christopherson). * Clear FRED VM entry/exit controls if FRED is not enumerated (Chao Gao). * Use guest_can_use() to trace FRED enumeration in a vcpu (Chao Gao). * Enable FRED MSRs intercept if FRED is no longer enumerated in CPUID (Chao Gao). * Move guest FRED states init into __vmx_vcpu_reset() (Chao Gao). * Don't use guest_cpuid_has() in vmx_prepare_switch_to_{host,guest}(), which are called from IRQ-disabled context (Chao Gao). * Reset msr_guest_fred_rsp0 in __vmx_vcpu_reset() (Chao Gao). * Fail host requested FRED MSRs access if KVM cannot virtualize FRED (Chao Gao). * Handle the case FRED MSRs are valid but KVM cannot virtualize FRED (Chao Gao). * Add sanity checks when writing to FRED MSRs. * Explain why it is ok to only check CR4.FRED in kvm_is_fred_enabled() (Chao Gao). * Document event data should be equal to CR2/DR6/IA32_XFD_ERR instead of using WARN_ON() (Chao Gao). * Zero event data if a #NM was not caused by extended feature disable (Chao Gao). * Set the nested flag when there is an original interrupt (Chao Gao). * Dump guest FRED states only if guest has FRED enabled (Nikolay Borisov). * Add a prerequisite to SHADOW_FIELD_R[OW] macros * Remove hyperv TLFS related changes (Jeremi Piotrowski). * Use kvm_cpu_cap_has() instead of cpu_feature_enabled() to decouple KVM's capability to virtualize a feature and host's enabling of a feature (Chao Gao). Xin Li (25): KVM: VMX: Cleanup VMX basic information defines and usages KVM: VMX: Cleanup VMX misc information defines and usages KVM: VMX: Add support for the secondary VM exit controls KVM: x86: Mark CR4.FRED as not reserved KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config KVM: VMX: Defer enabling FRED MSRs save/load until after set CPUID KVM: VMX: Set intercept for FRED MSRs KVM: VMX: Initialize VMCS FRED fields KVM: VMX: Switch FRED RSP0 between host and guest KVM: VMX: Add support for FRED context save/restore KVM: x86: Add kvm_is_fred_enabled() KVM: VMX: Handle FRED event data KVM: VMX: Handle VMX nested exception for FRED KVM: VMX: Disable FRED if FRED consistency checks fail KVM: VMX: Dump FRED context in dump_vmcs() KVM: VMX: Invoke vmx_set_cpu_caps() before nested setup KVM: nVMX: Add support for the secondary VM exit controls KVM: nVMX: Add a prerequisite to SHADOW_FIELD_R[OW] macros KVM: nVMX: Add FRED VMCS fields KVM: nVMX: Add support for VMX FRED controls KVM: nVMX: Add VMCS FRED states checking KVM: x86: Allow FRED/LKGS/WRMSRNS to be exposed to guests KVM: selftests: Run debug_regs test with FRED enabled KVM: selftests: Add a new VM guest mode to run user level code KVM: selftests: Add fred exception tests Documentation/virt/kvm/x86/nested-vmx.rst | 19 + arch/x86/include/asm/kvm_host.h | 8 +- arch/x86/include/asm/msr-index.h | 15 +- arch/x86/include/asm/vmx.h | 59 ++- arch/x86/kvm/cpuid.c | 4 +- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/kvm_cache_regs.h | 17 + arch/x86/kvm/svm/svm.c | 4 +- arch/x86/kvm/vmx/capabilities.h | 30 +- arch/x86/kvm/vmx/nested.c | 329 ++++++++++++--- arch/x86/kvm/vmx/nested.h | 2 +- arch/x86/kvm/vmx/vmcs.h | 1 + arch/x86/kvm/vmx/vmcs12.c | 19 + arch/x86/kvm/vmx/vmcs12.h | 38 ++ arch/x86/kvm/vmx/vmcs_shadow_fields.h | 80 ++-- arch/x86/kvm/vmx/vmx.c | 385 +++++++++++++++--- arch/x86/kvm/vmx/vmx.h | 15 +- arch/x86/kvm/x86.c | 103 ++++- arch/x86/kvm/x86.h | 5 +- tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/include/kvm_util_base.h | 1 + .../selftests/kvm/include/x86_64/processor.h | 36 ++ tools/testing/selftests/kvm/lib/kvm_util.c | 5 +- .../selftests/kvm/lib/x86_64/processor.c | 15 +- tools/testing/selftests/kvm/lib/x86_64/vmx.c | 4 +- .../testing/selftests/kvm/x86_64/debug_regs.c | 50 ++- .../testing/selftests/kvm/x86_64/fred_test.c | 297 ++++++++++++++ 27 files changed, 1320 insertions(+), 223 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/fred_test.c base-commit: e13841907b8fda0ae0ce1ec03684665f578416a8 -- 2.43.0

7 months, 3 weeks

8
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[PATCH] kunit: tool: Build compile_commands.json

by Brendan Jackman

compile_commands.json is used by clangd[1] to provide code navigation and completion functionality to editors. See [2] for an example configuration that includes this functionality for VSCode. It can currently be built manually when using kunit.py, by running: ./scripts/clang-tools/gen_compile_commands.py -d .kunit With this change however, it's built automatically so you don't need to manually keep it up to date. Unlike the manual approach, having make build the compile_commands.json means that it appears in the build output tree instead of at the root of the source tree, so you'll need to add --compile-commands-dir= to your clangd args for it to be found. [1] https://clangd.llvm.org/ [2] https://github.com/FlorentRevest/linux-kernel-vscode Signed-off-by: Brendan Jackman <jackmanb(a)google.com> --- tools/testing/kunit/kunit_kernel.py | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py index 7254c110ff23..61931c4926fd 100644 --- a/tools/testing/kunit/kunit_kernel.py +++ b/tools/testing/kunit/kunit_kernel.py @@ -72,7 +72,8 @@ class LinuxSourceTreeOperations: raise ConfigError(e.output.decode()) def make(self, jobs: int, build_dir: str, make_options: Optional[List[str]]) -> None: - command = ['make', 'ARCH=' + self._linux_arch, 'O=' + build_dir, '--jobs=' + str(jobs)] + command = ['make', 'all', 'compile_commands.json', 'ARCH=' + self._linux_arch, + 'O=' + build_dir, '--jobs=' + str(jobs)] if make_options: command.extend(make_options) if self._cross_compile: --- base-commit: 3c999d1ae3c75991902a1a7dad0cb62c2a3008b4 change-id: 20240516-kunit-compile-commands-d994074fc2be Best regards, -- Brendan Jackman <jackmanb(a)google.com>

8 months, 1 week

3
2
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[PATCH v3 0/7] iommufd support pasid attach/replace

by Yi Liu

PASID (Process Address Space ID) is a PCIe extension to tag the DMA transactions out of a physical device, and most modern IOMMU hardware have supported PASID granular address translation. So a PASID-capable device can be attached to multiple hwpts (a.k.a. domains), each attachment is tagged with a pasid. This series is based on a preparation series [1], it first adds a missing iommu API to replace domain for a pasid. Based on the iommu pasid attach/ replace/detach APIs, this series adds iommufd APIs for device drivers to attach/replace/detach pasid to/from hwpt per userspace's request, and adds selftest to validate the iommufd APIs. The completed code can be found in below link [2]. Heads up! The existing iommufd selftest was broken, there was a fix [3] to it, but not been upstreamed yet. If want to run the iommufd selftest, please apply that fix. Sorry for the inconvenience. [1] https://lore.kernel.org/linux-iommu/20240628085538.47049-1-yi.l.liu@intel.c… [2] https://github.com/yiliu1765/iommufd/tree/iommufd_pasid [3] https://lore.kernel.org/linux-iommu/20240111073213.180020-1-baolu.lu@linux.… Change log: v3: - Split the set_dev_pasid op enhancements for domain replacement to be a separate series "Make set_dev_pasid op supportting domain replacement" [1]. The below changes are made in the separate series. *) set_dev_pasid() callback should keep the old config if failed to attach to a domain. This simplifies the caller a lot as caller does not need to attach it back to old domain explicitly. This also avoids some corner cases in which the core may do duplicated domain attachment as described in below link (Jason) https://lore.kernel.org/linux-iommu/BN9PR11MB52768C98314A95AFCD2FA6478C0F2@… *) Drop patch 10 of v2 as it's a bug fix and can be submitted separately (Kevin) *) Rebase on top of Baolu's domain_alloc_paging refactor series (Jason) - Drop the attach_data which includes attach_fn and pasid, insteadly passing the pasid through the device attach path. (Jason) - Add a pasid-num-bits property to mock dev to make pasid selftest work (Kevin) v2: https://lore.kernel.org/linux-iommu/20240412081516.31168-1-yi.l.liu@intel.c… - Domain replace for pasid should be handled in set_dev_pasid() callbacks instead of remove_dev_pasid and call set_dev_pasid afteward in iommu layer (Jason) - Make xarray operations more self-contained in iommufd pasid attach/replace/detach (Jason) - Tweak the dev_iommu_get_max_pasids() to allow iommu driver to populate the max_pasids. This makes the iommufd selftest simpler to meet the max_pasids check in iommu_attach_device_pasid() (Jason) v1: https://lore.kernel.org/kvm/20231127063428.127436-1-yi.l.liu@intel.com/#r - Implemnet iommu_replace_device_pasid() to fall back to the original domain if this replacement failed (Kevin) - Add check in do_attach() to check corressponding attach_fn per the pasid value. rfc: https://lore.kernel.org/linux-iommu/20230926092651.17041-1-yi.l.liu@intel.c… Regards, Yi Liu Yi Liu (7): iommu: Introduce a replace API for device pasid iommufd: Pass pasid through the device attach/replace path iommufd: Support attach/replace hwpt per pasid iommufd/selftest: Add set_dev_pasid and remove_dev_pasid in mock iommu iommufd/selftest: Add a helper to get test device iommufd/selftest: Add test ops to test pasid attach/detach iommufd/selftest: Add coverage for iommufd pasid attach/detach drivers/iommu/iommu-priv.h | 3 + drivers/iommu/iommu.c | 80 ++++++- drivers/iommu/iommufd/Makefile | 1 + drivers/iommu/iommufd/device.c | 31 +-- drivers/iommu/iommufd/iommufd_private.h | 15 ++ drivers/iommu/iommufd/iommufd_test.h | 30 +++ drivers/iommu/iommufd/pasid.c | 157 +++++++++++++ drivers/iommu/iommufd/selftest.c | 206 ++++++++++++++++- include/linux/iommufd.h | 6 + tools/testing/selftests/iommu/iommufd.c | 207 ++++++++++++++++++ .../selftests/iommu/iommufd_fail_nth.c | 28 ++- tools/testing/selftests/iommu/iommufd_utils.h | 78 +++++++ 12 files changed, 808 insertions(+), 34 deletions(-) create mode 100644 drivers/iommu/iommufd/pasid.c -- 2.34.1

8 months, 2 weeks

4
13
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