From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E3451CFD376 for ; Sun, 30 Nov 2025 11:18:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4C9586B0023; Sun, 30 Nov 2025 06:18:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 451AE6B0024; Sun, 30 Nov 2025 06:18:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F2B16B0026; Sun, 30 Nov 2025 06:18:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 18A7D6B0023 for ; Sun, 30 Nov 2025 06:18:52 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id D86655D023 for ; Sun, 30 Nov 2025 11:18:51 +0000 (UTC) X-FDA: 84167026062.23.4EC5F4A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf13.hostedemail.com (Postfix) with ESMTP id 5801720002 for ; Sun, 30 Nov 2025 11:18:50 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZgJ9uLCf; spf=pass (imf13.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764501530; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=B3w1yDuYR8f1ZrmYm5y4DiqY8OTyh2ZdRmFabejW4m4=; b=eqhmTbGlq8UhTdnP/uGffOg+a+qePaF61QuMuUzFi5Dudk3XC5EtTZoSts5JXUZP5/Ck3p fEzSrtFTfVSGdUgYj7GzcqMjPNcn8MIzrBKOZqyDy58cDxx5JB5vSjn/XBbP6l+cS/jTsl 0zmjyoJ/8Cq10cSzV5uEfJhmnbvNzmI= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ZgJ9uLCf; spf=pass (imf13.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764501530; a=rsa-sha256; cv=none; b=gzjRsGtgS/s/VHpZ/SE6QqahWREgSsA2ph9+GJhujCRib2WrkkBOJN5m3bQ8Q8A6+yAN91 0BvMvrUN1YrZNqEwU5zuJZDIVW/ZBJhMb6PkojsT8Cfy5KSzGZ7NNgXVDZtzpAXe6vuPfm HA3ZoLucXkZlI5G/P/akHzr67BEdbeE= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id CED2D60156; Sun, 30 Nov 2025 11:18:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C503C4CEF8; Sun, 30 Nov 2025 11:18:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764501529; bh=Mv2TNIorv+Vl9StJ3rAHbansoPrEBArJPuXjfAYQx5k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZgJ9uLCflbDe4V56Zn+EhA12EOoiQEDWrl58/vwTrn/T4zlaUp6u7U3yzJWKNkAxr IiLbuZjOEiOHf8cf1oxIXvL+mkpo7nuKWwJtUhv6kZ5cCPBvMYAZuwSUksyQEhMRrN ESz3zJM8btnS19tBA/iOaUxlfzXqxaagg/uoN0X+ievjN5jI7dA9P7iL2kAF7WCwT9 FaGvriFrMqPQvu/eRl34K8I7AQjTDZ560xypBAsdG7aDOo+PzBJMAPOEbH06BfhH7W F1dhejn+vvbHZdH6tzG3bDJJLAt3vB03eLs3ueip6Ddi1Joqaj0QUxw0NIrBm29sLT 7Jk8HEn/9CCPg== From: Mike Rapoport To: linux-mm@kvack.org Cc: Andrea Arcangeli , Andrew Morton , Axel Rasmussen , Baolin Wang , David Hildenbrand , Hugh Dickins , James Houghton , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Nikita Kalyazin , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v3 5/5] KVM: selftests: test userfaultfd minor for guest_memfd Date: Sun, 30 Nov 2025 13:18:12 +0200 Message-ID: <20251130111812.699259-6-rppt@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251130111812.699259-1-rppt@kernel.org> References: <20251130111812.699259-1-rppt@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 5801720002 X-Rspamd-Server: rspam02 X-Stat-Signature: wubwzw9zt4uk3mh67j6f6qymyzn1qhy6 X-Rspam-User: X-HE-Tag: 1764501530-937986 X-HE-Meta: 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 p0fEqo3w ktgXP1ZIhHAmuiE+EMna4mmdnjO4OLnqkFXyO2V/FbxeFNpyllEDd3vLvofeSL/l9qgHeVFkpTkLp3NFaY9xXLqihhVojWgMII5XO2VOZJ9/LMcSjH7kGxJfcRvBBFxkN0NNzGnSyz3HLD+iMH3w09vH/2ldrGa1oPT23oRNgMSEy6TplI7crYolLu//izUlwZgTFbnSNeeNdPnC31045HtyVM8ZEItOTE2KzhkT7wL01zdWz3hji2FIBHnUWz9w6KPEHvZ7byoPFiYYzUPIKLOublBSjQfdQnu/k/GMUeijfjvv9uOZo7G2geDSOd07l5fiJsJNH18WJKyU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Nikita Kalyazin The test demonstrates that a minor userfaultfd event in guest_memfd can be resolved via a memcpy followed by a UFFDIO_CONTINUE ioctl. Acked-by: Liam R. Howlett Signed-off-by: Nikita Kalyazin Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) --- .../testing/selftests/kvm/guest_memfd_test.c | 97 +++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index e7d9aeb418d3..d0cf57d41cc9 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -10,13 +10,17 @@ #include #include #include +#include #include #include #include +#include #include #include #include +#include +#include #include "kvm_util.h" #include "test_util.h" @@ -254,6 +258,98 @@ static void test_guest_memfd_flags(struct kvm_vm *vm) } } +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_minor(int fd, size_t total_size) +{ + struct uffdio_api uffdio_api = { + .api = UFFD_API, + }; + struct uffdio_register uffd_reg; + struct uffdio_continue uffd_cont; + struct uffd_msg msg; + struct fault_args args; + pthread_t fault_thread; + void *mem, *mem_nofault; + int uffd, ret; + off_t offset = page_size; + void *fault_addr; + + uffd = syscall(__NR_userfaultfd, O_CLOEXEC); + TEST_ASSERT(uffd != -1, "userfaultfd creation should succeed"); + + 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"); + + mem_nofault = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem_nofault != MAP_FAILED, "mmap should succeed"); + + uffd_reg.range.start = (unsigned long)mem; + uffd_reg.range.len = total_size; + uffd_reg.mode = UFFDIO_REGISTER_MODE_MINOR; + 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"); + + memset(mem_nofault + offset, 0xaa, page_size); + + 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"); + + + 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"); + + /* + * wait for fault_thread to finish to make sure fault happened and was + * resolved before we verify the values + */ + ret = pthread_join(fault_thread, NULL); + TEST_ASSERT(ret == 0, "pthread_join should succeed"); + + TEST_ASSERT(args.value == *(char *)(mem_nofault + offset), + "memory should contain the value that was copied"); + TEST_ASSERT(args.value == *(char *)(mem + offset), + "no further fault is expected"); + + ret = munmap(mem_nofault, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); + close(uffd); +} + #define gmem_test(__test, __vm, __flags) \ do { \ int fd = vm_create_guest_memfd(__vm, page_size * 4, __flags); \ @@ -273,6 +369,7 @@ static void __test_guest_memfd(struct kvm_vm *vm, uint64_t flags) if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) { gmem_test(mmap_supported, vm, flags); gmem_test(fault_overflow, vm, flags); + gmem_test(uffd_minor, vm, flags); } else { gmem_test(fault_private, vm, flags); } -- 2.51.0