From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 E593441163F for ; Tue, 31 Mar 2026 15:33:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774971191; cv=none; b=lQg7VdH9kAQSLE4pf/220pojPFwonEfRRhhk7B9Uo6ESMI/PGqoG+5rNnjasMemH0AUhgnGwdIFha5lZJeIj7iAA47Q6eM/N5N3cfRwvxG148rc8JhjJN59jyEYiPCsUnrwUB9jEiNJLhE5gFV1I3pxyXIvKPH5wU3iYD4olEbk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774971191; c=relaxed/simple; bh=ldLHWwPcvqcTDwNP7L27St5+/SUJn4bKn+WlLfNiKEs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NI6Xcanrf78i9wHqtRSxI5FlJLNl/tl+7RyLNkewT1OYAKVV2NhycOwW+2q1++t9wurGZ2j5aGTbaRZLlp9s8m1OJePT0ahhPXrpPWkG5DnVbt7LHDQaLfzJdlrDyukhE7/X7nNLx4rkMWp1icqTxl+iyZ36fDmfMMzcSgfr/hI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EJYS05db; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EJYS05db" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774971178; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=i5UYRSpPluNiAHbbuPwAjSWApfYzLgHYEqbUe2e2eOg=; b=EJYS05dbPSkCxFKz2r/Tg6YkxCbpVyGtUcftrmYfVMY2GUeSKUO6tBsgb8yaf/f9lfq8QB 6uoCIUg5gdsf4VpeF0DTDXSEQ+bkppW82NMY2XISkjsJZuQ6JDP8gD8ifjrfg/SQCgdsZ8 PmPtHACyFlEY3ykwGrP233ycCB97LQs= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-346-L39KEl3ENpu0BTFkhdO_rQ-1; Tue, 31 Mar 2026 11:32:56 -0400 X-MC-Unique: L39KEl3ENpu0BTFkhdO_rQ-1 X-Mimecast-MFC-AGG-ID: L39KEl3ENpu0BTFkhdO_rQ_1774971175 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7ECC31944DC8; Tue, 31 Mar 2026 15:32:55 +0000 (UTC) Received: from localhost (unknown [10.72.116.55]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 747D030001A2; Tue, 31 Mar 2026 15:32:53 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Caleb Sander Mateos , Ming Lei Subject: [PATCH v2 10/10] selftests/ublk: add read-only buffer registration test Date: Tue, 31 Mar 2026 23:32:01 +0800 Message-ID: <20260331153207.3635125-11-ming.lei@redhat.com> In-Reply-To: <20260331153207.3635125-1-ming.lei@redhat.com> References: <20260331153207.3635125-1-ming.lei@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Add --rdonly_shmem_buf option to kublk that registers shared memory buffers with UBLK_SHMEM_BUF_READ_ONLY (read-only pinning without FOLL_WRITE) and mmaps with PROT_READ only. Add test_shmemzc_04.sh which exercises the new flag with a null target, hugetlbfs buffer, and write workload. Write I/O works because the server only reads from the shared buffer — the data flows from client to kernel to the shared pages, and the server reads them out. Signed-off-by: Ming Lei --- tools/testing/selftests/ublk/Makefile | 1 + tools/testing/selftests/ublk/kublk.c | 17 +++-- tools/testing/selftests/ublk/kublk.h | 1 + .../testing/selftests/ublk/test_shmemzc_04.sh | 72 +++++++++++++++++++ 4 files changed, 86 insertions(+), 5 deletions(-) create mode 100755 tools/testing/selftests/ublk/test_shmemzc_04.sh diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile index 3d1ad1730d93..d07f90fdd5b8 100644 --- a/tools/testing/selftests/ublk/Makefile +++ b/tools/testing/selftests/ublk/Makefile @@ -54,6 +54,7 @@ TEST_PROGS += test_part_02.sh TEST_PROGS += test_shmemzc_01.sh TEST_PROGS += test_shmemzc_02.sh TEST_PROGS += test_shmemzc_03.sh +TEST_PROGS += test_shmemzc_04.sh TEST_PROGS += test_stress_01.sh TEST_PROGS += test_stress_02.sh diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c index bd97e34f131b..7ed2fd5d6a0e 100644 --- a/tools/testing/selftests/ublk/kublk.c +++ b/tools/testing/selftests/ublk/kublk.c @@ -1212,11 +1212,13 @@ static void ublk_shmem_unregister_all(void) shmem_count = 0; } -static int ublk_ctrl_reg_buf(struct ublk_dev *dev, void *addr, size_t size) +static int ublk_ctrl_reg_buf(struct ublk_dev *dev, void *addr, size_t size, + __u32 flags) { - struct ublk_buf_reg buf_reg = { + struct ublk_shmem_buf_reg buf_reg = { .addr = (unsigned long)addr, .len = size, + .flags = flags, }; struct ublk_ctrl_cmd_data data = { .cmd_op = UBLK_U_CMD_REG_BUF, @@ -1265,7 +1267,7 @@ static void ublk_shmem_handle_client(int sock_fd, struct ublk_dev *dev) } /* Register server's VA range with kernel for PFN matching */ - ret = ublk_ctrl_reg_buf(dev, base, size); + ret = ublk_ctrl_reg_buf(dev, base, size, 0); if (ret < 0) { ublk_dbg(UBLK_DBG_DEV, "shmem_zc: kernel reg failed %d\n", ret); @@ -1350,7 +1352,8 @@ static int ublk_shmem_htlb_setup(const struct dev_ctx *ctx, return -EINVAL; } - base = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, + base = mmap(NULL, st.st_size, + ctx->rdonly_shmem_buf ? PROT_READ : PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, 0); if (base == MAP_FAILED) { ublk_err("htlb: mmap failed\n"); @@ -1358,7 +1361,8 @@ static int ublk_shmem_htlb_setup(const struct dev_ctx *ctx, return -ENOMEM; } - ret = ublk_ctrl_reg_buf(dev, base, st.st_size); + ret = ublk_ctrl_reg_buf(dev, base, st.st_size, + ctx->rdonly_shmem_buf ? UBLK_SHMEM_BUF_READ_ONLY : 0); if (ret < 0) { ublk_err("htlb: reg_buf failed: %d\n", ret); munmap(base, st.st_size); @@ -2122,6 +2126,7 @@ int main(int argc, char *argv[]) { "no_auto_part_scan", 0, NULL, 0 }, { "shmem_zc", 0, NULL, 0 }, { "htlb", 1, NULL, 0 }, + { "rdonly_shmem_buf", 0, NULL, 0 }, { 0, 0, 0, 0 } }; const struct ublk_tgt_ops *ops = NULL; @@ -2241,6 +2246,8 @@ int main(int argc, char *argv[]) ctx.flags |= UBLK_F_SHMEM_ZC; if (!strcmp(longopts[option_idx].name, "htlb")) ctx.htlb_path = strdup(optarg); + if (!strcmp(longopts[option_idx].name, "rdonly_shmem_buf")) + ctx.rdonly_shmem_buf = 1; break; case '?': /* diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h index 20d0a1eab41f..467af9f487e9 100644 --- a/tools/testing/selftests/ublk/kublk.h +++ b/tools/testing/selftests/ublk/kublk.h @@ -80,6 +80,7 @@ struct dev_ctx { unsigned int no_ublk_fixed_fd:1; unsigned int safe_stop:1; unsigned int no_auto_part_scan:1; + unsigned int rdonly_shmem_buf:1; __u32 integrity_flags; __u8 metadata_size; __u8 pi_offset; diff --git a/tools/testing/selftests/ublk/test_shmemzc_04.sh b/tools/testing/selftests/ublk/test_shmemzc_04.sh new file mode 100755 index 000000000000..899de088ece4 --- /dev/null +++ b/tools/testing/selftests/ublk/test_shmemzc_04.sh @@ -0,0 +1,72 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Test: shmem_zc with read-only buffer registration on null target +# +# Same as test_shmemzc_01 but with --rdonly_shmem_buf: pages are pinned +# without FOLL_WRITE (UBLK_BUF_F_READ). Write I/O works because +# the server only reads from the shared buffer. + +. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh + +ERR_CODE=0 + +_prep_test "shmem_zc" "null target hugetlbfs shmem zero-copy rdonly_buf test" + +if ! _have_program fio; then + echo "SKIP: fio not available" + exit "$UBLK_SKIP_CODE" +fi + +if ! grep -q hugetlbfs /proc/filesystems; then + echo "SKIP: hugetlbfs not supported" + exit "$UBLK_SKIP_CODE" +fi + +# Allocate hugepages +OLD_NR_HP=$(cat /proc/sys/vm/nr_hugepages) +echo 10 > /proc/sys/vm/nr_hugepages +NR_HP=$(cat /proc/sys/vm/nr_hugepages) +if [ "$NR_HP" -lt 2 ]; then + echo "SKIP: cannot allocate hugepages" + echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + exit "$UBLK_SKIP_CODE" +fi + +# Mount hugetlbfs +HTLB_MNT=$(mktemp -d "${UBLK_TEST_DIR}/htlb_mnt_XXXXXX") +if ! mount -t hugetlbfs none "$HTLB_MNT"; then + echo "SKIP: cannot mount hugetlbfs" + rmdir "$HTLB_MNT" + echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + exit "$UBLK_SKIP_CODE" +fi + +HTLB_FILE="$HTLB_MNT/ublk_buf" +fallocate -l 4M "$HTLB_FILE" + +dev_id=$(_add_ublk_dev -t null --shmem_zc --htlb "$HTLB_FILE" --rdonly_shmem_buf) +_check_add_dev $TID $? + +fio --name=htlb_zc_rdonly \ + --filename=/dev/ublkb"${dev_id}" \ + --ioengine=io_uring \ + --rw=randwrite \ + --direct=1 \ + --bs=4k \ + --size=4M \ + --iodepth=32 \ + --mem=mmaphuge:"$HTLB_FILE" \ + > /dev/null 2>&1 +ERR_CODE=$? + +# Delete device first so daemon releases the htlb mmap +_ublk_del_dev "${dev_id}" + +rm -f "$HTLB_FILE" +umount "$HTLB_MNT" +rmdir "$HTLB_MNT" +echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + +_cleanup_test "shmem_zc" + +_show_result $TID $ERR_CODE -- 2.53.0