From patchwork Wed Apr 2 16:07:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikita Kalyazin X-Patchwork-Id: 877840 Received: from smtp-fw-80006.amazon.com (smtp-fw-80006.amazon.com [99.78.197.217]) (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 68EB918A93F; Wed, 2 Apr 2025 16:08:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.217 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743610115; cv=none; b=BnxgkR6Od/Cl9Ci534vcdsklwEJFNkGw8nPDhzpX2fWcdoYm8ZHvUs39oF+za74FyKaMKki093HW3/nbBBuNZalgCBcjHrSLWrUSGEtHhwPoomytB7hk8x03VaXVSGC9V25B6QQrJexxNYM9aOZErOed4U5EwUVovBkX8hOYocs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743610115; c=relaxed/simple; bh=WkWQKhS8KSbPJpHhxFBFORgsn87AgnBtRaJ1fe4xHmg=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=M5X6AtSnZzZBpBgUCWKk4v+asMiDMykuuMNuo8JqCLE29g5QPuZZA58DgL+wXJ3Q12bkpdhAuJ/1pHhHH5x3yKOnvuifY+strMl5YM5sUzA+H/eZUEF8QrSDqCW8pdDNC2X0aVE8FTX0ObVU6622T7H8+bKfTHY7yaCTBM31YCQ= 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=SDPyTx8H; arc=none smtp.client-ip=99.78.197.217 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="SDPyTx8H" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1743610113; x=1775146113; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=wTofU1xt/dJK2QsInBbhwR8+NZ3Sv3EgYY1jxlgxsY4=; b=SDPyTx8HUsu9+fFVbOfcz6C4wmZ9vdcAiGHwVh35UYaBuqNQBPE7z2GM GmHhChtrd6NzE9Uc7k2gXe0ViuhjEJ+HqQdfbMkloDeXoqeclDicX2jCo BkPt3ecIp6BTscfMbCdqXXvzbVdEThmcNQfSn7RYPIbhy1+QfOkrAGOOe k=; X-IronPort-AV: E=Sophos;i="6.15,182,1739836800"; d="scan'208";a="37468501" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.214]) by smtp-border-fw-80006.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Apr 2025 16:08:30 +0000 Received: from EX19MTAUWA001.ant.amazon.com [10.0.21.151:61509] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.3.46:2525] with esmtp (Farcaster) id bacfcabb-94e1-4d19-a36d-27c598e119db; Wed, 2 Apr 2025 16:08:30 +0000 (UTC) X-Farcaster-Flow-ID: bacfcabb-94e1-4d19-a36d-27c598e119db Received: from EX19D020UWA003.ant.amazon.com (10.13.138.254) by EX19MTAUWA001.ant.amazon.com (10.250.64.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Wed, 2 Apr 2025 16:08:29 +0000 Received: from EX19MTAUWC002.ant.amazon.com (10.250.64.143) by EX19D020UWA003.ant.amazon.com (10.13.138.254) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Wed, 2 Apr 2025 16:08:29 +0000 Received: from email-imr-corp-prod-pdx-all-2b-f5cd2367.us-west-2.amazon.com (10.25.36.210) by mail-relay.amazon.com (10.250.64.149) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14 via Frontend Transport; Wed, 2 Apr 2025 16:08:29 +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-all-2b-f5cd2367.us-west-2.amazon.com (Postfix) with ESMTPS id 06432C061B; Wed, 2 Apr 2025 16:08:26 +0000 (UTC) From: Nikita Kalyazin To: , , CC: , , , , , , , , , , , , , , , , Subject: [PATCH v2 5/5] KVM: selftests: test userfaultfd minor for guest_memfd Date: Wed, 2 Apr 2025 16:07:21 +0000 Message-ID: <20250402160721.97596-6-kalyazin@amazon.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250402160721.97596-1-kalyazin@amazon.com> References: <20250402160721.97596-1-kalyazin@amazon.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The test demonstrates that a minor userfaultfd event in guest_memfd can be resolved via a memcpy followed by a UFFDIO_CONTINUE ioctl. Signed-off-by: Nikita Kalyazin --- .../testing/selftests/kvm/guest_memfd_test.c | 94 +++++++++++++++++++ 1 file changed, 94 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 38c501e49e0e..9b47b796f3aa 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" @@ -206,6 +210,93 @@ 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, *mem_nofault, *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"); + + 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"); + + 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"); + + memcpy(mem_nofault + offset, buf + offset, page_size); + + 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_nofault, total_size); + TEST_ASSERT(!ret, "munmap 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__ @@ -244,6 +335,9 @@ void test_vm_type(unsigned long type, bool is_shared) 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); }