From nobody Tue May 13 11:20:07 2025 Delivered-To: importer2@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer2=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1675285936; cv=none; d=zohomail.com; s=zohoarc; b=IIEH9dabc/w/hblyVn9FFf17asuYhZu6C6i1iecHW/D4CKtT9v3G3yG6ZYwicflSwRUvoHatcD87bc6aa5q43feImPyN5s48h2OteHu2Sf+2xz3Z6HS8EZw4LvX7rJHwpNPVAwho1YUwKA8K1d0EdHKeUoYptGF/cjlbN3x2SLI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1675285936; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=SKR76Zr2g1akCZyDSLQtn29eOmcOA4X4KkcFgLEjRlc=; b=HAzi2eLQSpZYkgyZasybxGyuY6Zo+BaFPTgFsZlVFKyc3FypNPURDCBADkvVnNa4rvzR8NxHzsO7soU7/CfWcirbD6UjdcI0pbjw2uG4BwZdRW1B2i/p3VtFywNaYOltjCQb+EyrL3Hzurlw9lckWObGOV0R+nXtQS/MlzDHbjQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer2=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1675285936175980.0293907457865; Wed, 1 Feb 2023 13:12:16 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNKNt-00077b-Gi; Wed, 01 Feb 2023 16:11:13 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNKNr-00076q-At for qemu-devel@nongnu.org; Wed, 01 Feb 2023 16:11:11 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNKNn-0003MA-LN for qemu-devel@nongnu.org; Wed, 01 Feb 2023 16:11:11 -0500 Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-436-8jvXvBFYPSCzDaET8Ts8FA-1; Wed, 01 Feb 2023 16:11:06 -0500 Received: by mail-qt1-f197.google.com with SMTP id l3-20020a05622a174300b003b9b6101f65so2575052qtk.11 for ; Wed, 01 Feb 2023 13:11:06 -0800 (PST) Received: from x1n.redhat.com (bras-base-aurron9127w-grc-56-70-30-145-63.dsl.bell.ca. [70.30.145.63]) by smtp.gmail.com with ESMTPSA id ea17-20020a05620a489100b007204305dee4sm6331403qkb.19.2023.02.01.13.11.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Feb 2023 13:11:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675285867; 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=SKR76Zr2g1akCZyDSLQtn29eOmcOA4X4KkcFgLEjRlc=; b=YeUuyRtRH/b0CTu+Jk15OoMKemiptxl258ClfIf+rEH1mayYogK8qMHOZZIeWwiYuUtEpN CYoN5VDCcVJICWPGeu/qVmVc8ft02vlDllkdRfPhWGAqp3lASGevauZZlucnM4CLbUdmD1 PwoSC7yPD1r+VKwwxvNvBqE77TLlkFs= X-MC-Unique: 8jvXvBFYPSCzDaET8Ts8FA-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SKR76Zr2g1akCZyDSLQtn29eOmcOA4X4KkcFgLEjRlc=; b=VoWl+4+FQTEK4iithRiWL9JZpcoaWo+egokkB9Ra7mT1x9FwuOQtSnsNDd+idI6Rlk mp7XMUr3uF6iH0swnLNvpnsF1sfcBYjkSX0oAF78iq8k4qatNqkzJrjpxNQrCcFKRsOx 2r1pIxEvOdYUovgzuFs+fOHk9R7zdsjxsgkP9NBirfjf423Uo+5DQC802c9R4cQPF/ol MKw/fVZhpNY7JGKNpkwPeTO5vAUGi+Vk6+9FGySZxxd2ni5jtTcPFPbYjh/DYdnkQkw7 7lkVxPdmfQD0Zi8Q+fKGnQ9mQkbJZggu8GtVl/1zwrj4VEh9ZMPPv/dVeXJG/EW1K2KS V1Cg== X-Gm-Message-State: AO0yUKWxMe9esnwohzyTE7czDxYvrHBP18uX9QRQP40jj5M0tnq6ebB3 +u4xS7fsCXIlW6Ok+UeSTH02Xo9Qk+nIC8d4RJl/gRRX6CzCIJ+LZScGfT+P99EH8DrFHUNw4RJ nYH6Ohzc0UsiIkgyP1zcVjxyCLEghDHXOYmmE+CW2A+ByjiZmNuDrjhfW8Iii3PJx X-Received: by 2002:a05:622a:41c3:b0:3b8:36f8:830e with SMTP id ce3-20020a05622a41c300b003b836f8830emr5229872qtb.6.1675285864869; Wed, 01 Feb 2023 13:11:04 -0800 (PST) X-Google-Smtp-Source: AK7set8Fl9mXjpYFhB8uiN6VCqoEgFDProc9/ZO6ZAVlP7IjuRi2/+B77l6Y/bvBg55mN/uqZbLW+A== X-Received: by 2002:a05:622a:41c3:b0:3b8:36f8:830e with SMTP id ce3-20020a05622a41c300b003b836f8830emr5229837qtb.6.1675285864484; Wed, 01 Feb 2023 13:11:04 -0800 (PST) From: Peter Xu To: qemu-devel@nongnu.org Cc: Leonardo Bras Soares Passos , Juan Quintela , =?UTF-8?q?Michal=20Pr=C3=ADvozn=C3=ADk?= , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , peterx@redhat.com, =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , "Dr . David Alan Gilbert" Subject: [PATCH v2 2/3] util/userfaultfd: Add uffd_open() Date: Wed, 1 Feb 2023 16:10:54 -0500 Message-Id: <20230201211055.649442-3-peterx@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20230201211055.649442-1-peterx@redhat.com> References: <20230201211055.649442-1-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer2=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer2=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer2=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1675285938368100007 Add a helper to create the uffd handle. Reviewed-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: Peter Xu Reviewed-by: Juan Quintela --- include/qemu/userfaultfd.h | 8 ++++++++ migration/postcopy-ram.c | 11 +++++------ tests/qtest/migration-test.c | 3 ++- util/userfaultfd.c | 13 +++++++++++-- 4 files changed, 26 insertions(+), 9 deletions(-) diff --git a/include/qemu/userfaultfd.h b/include/qemu/userfaultfd.h index 6b74f92792..2101115f70 100644 --- a/include/qemu/userfaultfd.h +++ b/include/qemu/userfaultfd.h @@ -17,6 +17,14 @@ #include "exec/hwaddr.h" #include =20 +/** + * uffd_open(): Open an userfaultfd handle for current context. + * + * @flags: The flags we want to pass in when creating the handle. + * + * Returns: the uffd handle if >=3D0, or <0 if error happens. + */ +int uffd_open(int flags); int uffd_query_features(uint64_t *features); int uffd_create_fd(uint64_t features, bool non_blocking); void uffd_close_fd(int uffd_fd); diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index b9a37ef255..0c55df0e52 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -37,6 +37,7 @@ #include "qemu-file.h" #include "yank_functions.h" #include "tls.h" +#include "qemu/userfaultfd.h" =20 /* Arbitrary limit on size of each discard command, * keeps them around ~200 bytes @@ -226,11 +227,9 @@ static bool receive_ufd_features(uint64_t *features) int ufd; bool ret =3D true; =20 - /* if we are here __NR_userfaultfd should exists */ - ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + ufd =3D uffd_open(O_CLOEXEC); if (ufd =3D=3D -1) { - error_report("%s: syscall __NR_userfaultfd failed: %s", __func__, - strerror(errno)); + error_report("%s: uffd_open() failed: %s", __func__, strerror(errn= o)); return false; } =20 @@ -375,7 +374,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingSt= ate *mis) goto out; } =20 - ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + ufd =3D uffd_open(O_CLOEXEC); if (ufd =3D=3D -1) { error_report("%s: userfaultfd not available: %s", __func__, strerror(errno)); @@ -1160,7 +1159,7 @@ static int postcopy_temp_pages_setup(MigrationIncomin= gState *mis) int postcopy_ram_incoming_setup(MigrationIncomingState *mis) { /* Open the fd for the kernel to give us userfaults */ - mis->userfault_fd =3D syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK= ); + mis->userfault_fd =3D uffd_open(O_CLOEXEC | O_NONBLOCK); if (mis->userfault_fd =3D=3D -1) { error_report("%s: Failed to open userfault fd: %s", __func__, strerror(errno)); diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c index 1dd32c9506..7a5d1922dd 100644 --- a/tests/qtest/migration-test.c +++ b/tests/qtest/migration-test.c @@ -62,13 +62,14 @@ static bool uffd_feature_thread_id; #include #include #include +#include "qemu/userfaultfd.h" =20 static bool ufd_version_check(void) { struct uffdio_api api_struct; uint64_t ioctl_mask; =20 - int ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + int ufd =3D uffd_open(O_CLOEXEC); =20 if (ufd =3D=3D -1) { g_test_message("Skipping test: userfaultfd not available"); diff --git a/util/userfaultfd.c b/util/userfaultfd.c index f1cd6af2b1..9845a2ec81 100644 --- a/util/userfaultfd.c +++ b/util/userfaultfd.c @@ -19,6 +19,15 @@ #include #include =20 +int uffd_open(int flags) +{ +#if defined(__linux__) && defined(__NR_userfaultfd) + return syscall(__NR_userfaultfd, flags); +#else + return -EINVAL; +#endif +} + /** * uffd_query_features: query UFFD features * @@ -32,7 +41,7 @@ int uffd_query_features(uint64_t *features) struct uffdio_api api_struct =3D { 0 }; int ret =3D -1; =20 - uffd_fd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + uffd_fd =3D uffd_open(O_CLOEXEC); if (uffd_fd < 0) { trace_uffd_query_features_nosys(errno); return -1; @@ -69,7 +78,7 @@ int uffd_create_fd(uint64_t features, bool non_blocking) uint64_t ioctl_mask =3D BIT(_UFFDIO_REGISTER) | BIT(_UFFDIO_UNREGISTER= ); =20 flags =3D O_CLOEXEC | (non_blocking ? O_NONBLOCK : 0); - uffd_fd =3D syscall(__NR_userfaultfd, flags); + uffd_fd =3D uffd_open(flags); if (uffd_fd < 0) { trace_uffd_create_fd_nosys(errno); return -1; --=20 2.37.3