From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8DE123914E1 for ; Mon, 6 Apr 2026 17:50:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775497846; cv=none; b=XsUJCRDQYX9/lzr4tX/zTVAaclBgv7uCG6FQSpvqHauAKs8XHqkh824eLdnh7niUR+BiWBw32n+2+/ZP58kmJkGmuib6DozvuQNikIEoa2jaRlQoI3UmTEU51hchNibo3EvB52cGIiFkA1xPa2E7Ny0KNDnSW/uteY9PLgbadkY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775497846; c=relaxed/simple; bh=TXQyxwkVH+dQ3wxVBrPJHs2Cmrv4LaCHu1SY+Yiqe58=; h=Date:To:From:Subject:Message-Id; b=deV6+mqinTcpGY+XRRIDKKVDRnm+X4Ht0cdjeeH6AtO+ERBeYl63QkFHdQQoIIvWio9G3trib5rwBmkl1BobSYHaW/HJ3Ap10Lab2wOOjl4LnxVfW/qo2UHg1HJTKki8GvlitAyNh6lHe6PWyR7UnddLSU6lE0luaJUothMifaw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=FApEDMwK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FApEDMwK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37D9DC4CEF7; Mon, 6 Apr 2026 17:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1775497846; bh=TXQyxwkVH+dQ3wxVBrPJHs2Cmrv4LaCHu1SY+Yiqe58=; h=Date:To:From:Subject:From; b=FApEDMwK9qfbpz31veMlVV/oM3wZ5KbUpJoxT3Qix0nrQzdop0visMA1SxDDIINQq 0PcVlezlboxc94rmvu4Wm0NL3CQUVReVLnDpsc0kOwAN//0VqAKArRi5Z1ZzFT/A63 J/mnNICcRsmrakc6OZBanlfNxsOvlMi0S6hi2uzc= Date: Mon, 06 Apr 2026 10:50:45 -0700 To: mm-commits@vger.kernel.org,willy@infradead.org,vbabka@suse.cz,surenb@google.com,shuah@kernel.org,seanjc@google.com,rppt@kernel.org,peterx@redhat.com,pbonzini@redhat.com,osalvador@suse.de,muchun.song@linux.dev,mhocko@suse.com,ljs@kernel.org,liam.howlett@oracle.com,jthoughton@google.com,hughd@google.com,harry.yoo@oracle.com,harry@kernel.org,david@kernel.org,baolin.wang@linux.alibaba.com,axelrasmussen@google.com,avagin@google.com,aarcange@redhat.com,kalyazin@amazon.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] kvm-selftests-test-userfaultfd-missing-for-guest_memfd.patch removed from -mm tree Message-Id: <20260406175046.37D9DC4CEF7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: KVM: selftests: test userfaultfd missing for guest_memfd has been removed from the -mm tree. Its filename was kvm-selftests-test-userfaultfd-missing-for-guest_memfd.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Nikita Kalyazin Subject: KVM: selftests: test userfaultfd missing for guest_memfd Date: Thu, 2 Apr 2026 07:11:56 +0300 The test demonstrates that a missing userfaultfd event in guest_memfd can be resolved via a UFFDIO_COPY ioctl. Link: https://lkml.kernel.org/r/20260402041156.1377214-16-rppt@kernel.org Signed-off-by: Nikita Kalyazin Signed-off-by: Mike Rapoport (Microsoft) Cc: Andrea Arcangeli Cc: Andrei Vagin Cc: Axel Rasmussen Cc: Baolin Wang Cc: David Hildenbrand (Arm) Cc: Harry Yoo Cc: Harry Yoo (Oracle) Cc: Hugh Dickins Cc: James Houghton Cc: Liam Howlett Cc: Lorenzo Stoakes (Oracle) Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Muchun Song Cc: Oscar Salvador Cc: Paolo Bonzini Cc: Peter Xu Cc: Sean Christopherson Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- tools/testing/selftests/kvm/guest_memfd_test.c | 80 ++++++++++++++- 1 file changed, 79 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/kvm/guest_memfd_test.c~kvm-selftests-test-userfaultfd-missing-for-guest_memfd +++ a/tools/testing/selftests/kvm/guest_memfd_test.c @@ -439,6 +439,82 @@ static void test_uffd_minor(int fd, size close(uffd); } +static void test_uffd_missing(int fd, size_t total_size) +{ + struct uffdio_register uffd_reg; + struct uffdio_copy uffd_copy; + struct uffd_msg msg; + struct fault_args args; + pthread_t fault_thread; + void *mem, *buf = NULL; + int uffd, ret; + off_t offset = page_size; + void *fault_addr; + const char test_val = 0xab; + + ret = posix_memalign(&buf, page_size, total_size); + TEST_ASSERT_EQ(ret, 0); + memset(buf, test_val, total_size); + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC); + TEST_ASSERT(uffd != -1, "userfaultfd creation should succeed"); + + struct uffdio_api uffdio_api = { + .api = UFFD_API, + .features = 0, + }; + ret = ioctl(uffd, UFFDIO_API, &uffdio_api); + TEST_ASSERT(ret != -1, "ioctl(UFFDIO_API) should succeed"); + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap should succeed"); + + uffd_reg.range.start = (unsigned long)mem; + uffd_reg.range.len = total_size; + uffd_reg.mode = UFFDIO_REGISTER_MODE_MISSING; + ret = ioctl(uffd, UFFDIO_REGISTER, &uffd_reg); + TEST_ASSERT(ret != -1, "ioctl(UFFDIO_REGISTER) should succeed"); + + fault_addr = mem + offset; + args.addr = fault_addr; + + ret = pthread_create(&fault_thread, NULL, fault_thread_fn, &args); + TEST_ASSERT(ret == 0, "pthread_create should succeed"); + + ret = read(uffd, &msg, sizeof(msg)); + TEST_ASSERT(ret != -1, "read from userfaultfd should succeed"); + TEST_ASSERT(msg.event == UFFD_EVENT_PAGEFAULT, "event type should be pagefault"); + TEST_ASSERT((void *)(msg.arg.pagefault.address & ~(page_size - 1)) == fault_addr, + "pagefault should occur at expected address"); + TEST_ASSERT(!(msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP), + "pagefault should not be write-protect"); + + uffd_copy.dst = (unsigned long)fault_addr; + uffd_copy.src = (unsigned long)(buf + offset); + uffd_copy.len = page_size; + uffd_copy.mode = 0; + ret = ioctl(uffd, UFFDIO_COPY, &uffd_copy); + TEST_ASSERT(ret != -1, "ioctl(UFFDIO_COPY) should succeed"); + + /* Wait for the faulting thread to complete - this provides the memory barrier */ + ret = pthread_join(fault_thread, NULL); + TEST_ASSERT(ret == 0, "pthread_join should succeed"); + + /* + * Now it's safe to check args.value - the thread has completed + * and memory is synchronized + */ + TEST_ASSERT(args.value == test_val, + "memory should contain the value that was copied"); + TEST_ASSERT(*(char *)(mem + offset) == test_val, + "no further fault is expected"); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); + free(buf); + close(uffd); +} + static void test_guest_memfd_flags(struct kvm_vm *vm) { uint64_t valid_flags = vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS); @@ -494,8 +570,10 @@ static void __test_guest_memfd(struct kv gmem_test(fallocate, vm, flags); gmem_test(invalid_punch_hole, vm, flags); - if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) + if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) { gmem_test(uffd_minor, vm, flags); + gmem_test(uffd_missing, vm, flags); + } } static void test_guest_memfd(unsigned long vm_type) _ Patches currently in -mm which might be from kalyazin@amazon.com are