From patchwork Mon Mar 3 13:30:11 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikita Kalyazin X-Patchwork-Id: 13998870 Received: from smtp-fw-2101.amazon.com (smtp-fw-2101.amazon.com [72.21.196.25]) (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 107C82116F3; Mon, 3 Mar 2025 13:31:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=72.21.196.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741008702; cv=none; b=Ege9Tn35AK1sZNEfZM95Po5zYR8reb24Zq7e8+MKl3V4k+0UcbWLJp9dNR3fFft16HCP7mTw2pvHPDIkdYREhI161Qm80BnzRieCorauYwhaMPHDu7FWPqJnr0WSEpTTYOy+IQ3x6FM3FoRrZI7Or3584L8/HeYmEE3VEXPjEXU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741008702; c=relaxed/simple; bh=gLzufxXzt0l7nygEjLB/9ni9EbV3R+EdI/i1bDBrI2E=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=JDBaC3KJRV3DK6Fem8IijRz2GKUj5liPUjTLgVXpLYUbzvxutcOVn7TIvW3dFGmHXdaYCjg6VNQCeZuVQ5VEm8/uEyam5mReVidSSxpM2JcIek1IBvR4acAMrjmnX0UlbHsFK6mIZq3qPzNp1ETTw3qWA3iOklPHV+pCdZJWorU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.uk; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=NWsY9fXc; arc=none smtp.client-ip=72.21.196.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="NWsY9fXc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1741008702; x=1772544702; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Q0UMU0w4P1V9x66iYOqq2hXEUmMMf6XfFEDXRgYhyWI=; b=NWsY9fXc8VV3NtzairQ/1WCfJY9h+CasXUQ14nnp6bU0QVm2kOkK5uop gsNlWGgJ9herXLcNhZxEfEE+UkkOviUqchIkXQ0Tu9ZC7SM2nDGxJU4rv XyOgYzmKu8fMRNmqWkQWpdekP/GGQwWnwh5B++uDBDzjwiP99SpyYwLTe I=; X-IronPort-AV: E=Sophos;i="6.13,329,1732579200"; d="scan'208";a="471520831" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-2101.iad2.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2025 13:31:23 +0000 Received: from EX19MTAUWC002.ant.amazon.com [10.0.7.35:52084] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.52.238:2525] with esmtp (Farcaster) id 138b0d45-31f1-425a-a923-c15034519930; Mon, 3 Mar 2025 13:31:22 +0000 (UTC) X-Farcaster-Flow-ID: 138b0d45-31f1-425a-a923-c15034519930 Received: from EX19D020UWC004.ant.amazon.com (10.13.138.149) by EX19MTAUWC002.ant.amazon.com (10.250.64.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 3 Mar 2025 13:31:22 +0000 Received: from EX19MTAUWA001.ant.amazon.com (10.250.64.204) by EX19D020UWC004.ant.amazon.com (10.13.138.149) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 3 Mar 2025 13:31:21 +0000 Received: from email-imr-corp-prod-pdx-1box-2b-ecca39fb.us-west-2.amazon.com (10.25.36.214) by mail-relay.amazon.com (10.250.64.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14 via Frontend Transport; Mon, 3 Mar 2025 13:31:21 +0000 Received: from dev-dsk-kalyazin-1a-a12e27e2.eu-west-1.amazon.com (dev-dsk-kalyazin-1a-a12e27e2.eu-west-1.amazon.com [172.19.103.116]) by email-imr-corp-prod-pdx-1box-2b-ecca39fb.us-west-2.amazon.com (Postfix) with ESMTPS id EF588803CC; Mon, 3 Mar 2025 13:31:18 +0000 (UTC) From: Nikita Kalyazin To: , , CC: , , , , , , , , , , , , , , , , Subject: [RFC PATCH 5/5] KVM: selftests: add uffd missing test for guest_memfd Date: Mon, 3 Mar 2025 13:30:11 +0000 Message-ID: <20250303133011.44095-6-kalyazin@amazon.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250303133011.44095-1-kalyazin@amazon.com> References: <20250303133011.44095-1-kalyazin@amazon.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The test demonstrates how a page missing event can be resolved via write syscall followed by UFFDIO_CONTINUE ioctl. Signed-off-by: Nikita Kalyazin --- .../testing/selftests/kvm/guest_memfd_test.c | 88 +++++++++++++++++++ 1 file changed, 88 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index b07221aa54c9..aea0e8627981 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -10,12 +10,16 @@ #include #include #include +#include #include #include +#include #include #include #include +#include +#include #include "kvm_util.h" #include "test_util.h" @@ -278,6 +282,88 @@ static void test_create_guest_memfd_multiple(struct kvm_vm *vm) close(fd1); } +struct fault_args { + char *addr; + volatile char value; +}; + +static void *fault_thread_fn(void *arg) +{ + struct fault_args *args = arg; + + /* Trigger page fault */ + args->value = *args->addr; + return NULL; +} + +static void test_uffd_missing(int fd, size_t page_size, size_t total_size) +{ + struct uffdio_register uffd_reg; + struct uffdio_continue uffd_cont; + 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; + + ret = posix_memalign(&buf, page_size, total_size); + TEST_ASSERT_EQ(ret, 0); + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC); + TEST_ASSERT(uffd != -1, "userfaultfd creation should succeed"); + + struct uffdio_api uffdio_api = { + .api = UFFD_API, + .features = UFFD_FEATURE_MISSING_SHMEM, + }; + 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"); + + ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, + offset, page_size); + TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) 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"); + + ret = pwrite(fd, buf + offset, page_size, offset); + TEST_ASSERT(ret == page_size, "write should succeed"); + + uffd_cont.range.start = (unsigned long)fault_addr; + uffd_cont.range.len = page_size; + uffd_cont.mode = 0; + ret = ioctl(uffd, UFFDIO_CONTINUE, &uffd_cont); + TEST_ASSERT(ret != -1, "ioctl(UFFDIO_CONTINUE) should succeed"); + + ret = pthread_join(fault_thread, NULL); + TEST_ASSERT(ret == 0, "pthread_join should succeed"); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); + free(buf); + close(uffd); +} + unsigned long get_shared_type(void) { #ifdef __x86_64__ @@ -316,6 +402,8 @@ void test_vm_type(unsigned long type, bool is_shared) test_file_size(fd, page_size, total_size); test_fallocate(fd, page_size, total_size); test_invalid_punch_hole(fd, page_size, total_size); + if (is_shared) + test_uffd_missing(fd, page_size, total_size); close(fd); kvm_vm_release(vm);