From patchwork Fri Mar 19 10:12:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12150653 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CEBEC433E0 for ; Fri, 19 Mar 2021 10:26:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AF58164F40 for ; Fri, 19 Mar 2021 10:26:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF58164F40 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49166 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lNCLA-0006lG-Ob for qemu-devel@archiver.kernel.org; Fri, 19 Mar 2021 06:26:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47916) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lNC93-0001ty-7t for qemu-devel@nongnu.org; Fri, 19 Mar 2021 06:14:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:34580) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lNC91-0000Z3-0h for qemu-devel@nongnu.org; Fri, 19 Mar 2021 06:14:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616148854; 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=r4IPLBGuTr5EPUqfwdaOnRCbvfW9tuWS7XZe3Bbyx/w=; b=H2njrdd5sMTicxwNkRE01iV5HwOPJsVQS8WptoTIdnGTBziaM07hPn/BWLkbJyMuXYh2DX TCgoQyktqqOhE591aSJt4nOraUukxnZ7uXTT0V59At+hAl4iFp3WGB1HDEudV+7btJl28o BcV7iNQgFkEZyShtDCR1W6vLv0uoeCw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-147-HpyCZx5BNF2O1r2ihr1sGA-1; Fri, 19 Mar 2021 06:14:10 -0400 X-MC-Unique: HpyCZx5BNF2O1r2ihr1sGA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 754C3107ACCA; Fri, 19 Mar 2021 10:14:09 +0000 (UTC) Received: from t480s.redhat.com (ovpn-112-11.ams2.redhat.com [10.36.112.11]) by smtp.corp.redhat.com (Postfix) with ESMTP id 08E1510013C1; Fri, 19 Mar 2021 10:14:05 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v4 09/14] util/mmap-alloc: Pass flags instead of separate bools to qemu_ram_mmap() Date: Fri, 19 Mar 2021 11:12:25 +0100 Message-Id: <20210319101230.21531-10-david@redhat.com> In-Reply-To: <20210319101230.21531-1-david@redhat.com> References: <20210319101230.21531-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.249, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marcel Apfelbaum , Murilo Opsfelder Araujo , Igor Kotrasinski , Eduardo Habkost , "Michael S. Tsirkin" , David Hildenbrand , Richard Henderson , "Dr. David Alan Gilbert" , Peter Xu , Greg Kurz , Stefan Hajnoczi , Igor Mammedov , Paolo Bonzini , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Let's pass flags instead of bools to prepare for passing other flags and update the documentation of qemu_ram_mmap(). Introduce new QEMU_MAP_ flags that abstract the mmap() PROT_ and MAP_ flag handling and simplify it. We expose only flags that are currently supported by qemu_ram_mmap(). Maybe, we'll see qemu_mmap() in the future as well that can implement these flags. Note: We don't use MAP_ flags as some flags (e.g., MAP_SYNC) are only defined for some systems and we want to always be able to identify these flags reliably inside qemu_ram_mmap() -- for example, to properly warn when some future flags are not available or effective on a system. Also, this way we can simplify PROT_ handling as well. Signed-off-by: David Hildenbrand Reviewed-by: Peter Xu --- include/qemu/mmap-alloc.h | 16 +++++++++------- include/qemu/osdep.h | 18 ++++++++++++++++++ softmmu/physmem.c | 8 +++++--- util/mmap-alloc.c | 15 ++++++++------- util/oslib-posix.c | 3 ++- 5 files changed, 42 insertions(+), 18 deletions(-) diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h index 456ff87df1..a60a2085b3 100644 --- a/include/qemu/mmap-alloc.h +++ b/include/qemu/mmap-alloc.h @@ -7,18 +7,22 @@ size_t qemu_fd_getpagesize(int fd); size_t qemu_mempath_getpagesize(const char *mem_path); /** - * qemu_ram_mmap: mmap the specified file or device. + * qemu_ram_mmap: mmap anonymous memory, the specified file or device. + * + * mmap() abstraction to map guest RAM, simplifying flag handling, taking + * care of alignment requirements and installing guard pages. * * Parameters: * @fd: the file or the device to mmap * @size: the number of bytes to be mmaped * @align: if not zero, specify the alignment of the starting mapping address; * otherwise, the alignment in use will be determined by QEMU. - * @readonly: true for a read-only mapping, false for read/write. - * @shared: map has RAM_SHARED flag. - * @is_pmem: map has RAM_PMEM flag. + * @qemu_map_flags: QEMU_MAP_* flags * @map_offset: map starts at offset of map_offset from the start of fd * + * Internally, MAP PRIVATE, MAP_ANONYMOUS and MAP_SHARED_VALIDATE are set + * implicitly based on other parameters. + * * Return: * On success, return a pointer to the mapped area. * On failure, return MAP_FAILED. @@ -26,9 +30,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path); void *qemu_ram_mmap(int fd, size_t size, size_t align, - bool readonly, - bool shared, - bool is_pmem, + uint32_t qemu_map_flags, off_t map_offset); void qemu_ram_munmap(int fd, void *ptr, size_t size); diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index ba15be9c56..5ba89f5460 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -347,6 +347,24 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared); void qemu_vfree(void *ptr); void qemu_anon_ram_free(void *ptr, size_t size); +/* + * Abstraction of PROT_ and MAP_ flags as passed to mmap(), for example, + * consumed by qemu_ram_mmap(). + */ + +/* Map PROT_READ instead of PROT_READ | PROT_WRITE. */ +#define QEMU_MAP_READONLY (1 << 0) + +/* Use MAP_SHARED instead of MAP_PRIVATE. */ +#define QEMU_MAP_SHARED (1 << 1) + +/* + * Use MAP_SYNC | MAP_SHARED_VALIDATE if supported. Ignored without + * QEMU_MAP_SHARED. If mapping fails, warn and fallback to !QEMU_MAP_SYNC. + */ +#define QEMU_MAP_SYNC (1 << 2) + + #define QEMU_MADV_INVALID -1 #if defined(CONFIG_MADVISE) diff --git a/softmmu/physmem.c b/softmmu/physmem.c index fdcd38ba61..d1a1a6b72e 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -1533,6 +1533,7 @@ static void *file_ram_alloc(RAMBlock *block, off_t offset, Error **errp) { + uint32_t qemu_map_flags; void *area; block->page_size = qemu_fd_getpagesize(fd); @@ -1580,9 +1581,10 @@ static void *file_ram_alloc(RAMBlock *block, perror("ftruncate"); } - area = qemu_ram_mmap(fd, memory, block->mr->align, readonly, - block->flags & RAM_SHARED, block->flags & RAM_PMEM, - offset); + qemu_map_flags = readonly ? QEMU_MAP_READONLY : 0; + qemu_map_flags |= (block->flags & RAM_SHARED) ? QEMU_MAP_SHARED : 0; + qemu_map_flags |= (block->flags & RAM_PMEM) ? QEMU_MAP_SYNC : 0; + area = qemu_ram_mmap(fd, memory, block->mr->align, qemu_map_flags, offset); if (area == MAP_FAILED) { error_setg_errno(errp, errno, "unable to map backing store for guest RAM"); diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 0e2bd7bc0e..1ddc0e2a1e 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -118,9 +118,12 @@ static void *mmap_reserve(size_t size, int fd) * Activate memory in a reserved region from the given fd (if any), to make * it accessible. */ -static void *mmap_activate(void *ptr, size_t size, int fd, bool readonly, - bool shared, bool is_pmem, off_t map_offset) +static void *mmap_activate(void *ptr, size_t size, int fd, + uint32_t qemu_map_flags, off_t map_offset) { + const bool readonly = qemu_map_flags & QEMU_MAP_READONLY; + const bool shared = qemu_map_flags & QEMU_MAP_SHARED; + const bool sync = qemu_map_flags & QEMU_MAP_SYNC; const int prot = PROT_READ | (readonly ? 0 : PROT_WRITE); int map_sync_flags = 0; int flags = MAP_FIXED; @@ -128,7 +131,7 @@ static void *mmap_activate(void *ptr, size_t size, int fd, bool readonly, flags |= fd == -1 ? MAP_ANONYMOUS : 0; flags |= shared ? MAP_SHARED : MAP_PRIVATE; - if (shared && is_pmem) { + if (shared && sync) { map_sync_flags = MAP_SYNC | MAP_SHARED_VALIDATE; } @@ -173,9 +176,7 @@ static inline size_t mmap_guard_pagesize(int fd) void *qemu_ram_mmap(int fd, size_t size, size_t align, - bool readonly, - bool shared, - bool is_pmem, + uint32_t qemu_map_flags, off_t map_offset) { const size_t guard_pagesize = mmap_guard_pagesize(fd); @@ -199,7 +200,7 @@ void *qemu_ram_mmap(int fd, offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; - ptr = mmap_activate(guardptr + offset, size, fd, readonly, shared, is_pmem, + ptr = mmap_activate(guardptr + offset, size, fd, qemu_map_flags, map_offset); if (ptr == MAP_FAILED) { munmap(guardptr, total); diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 36820fec16..c12108c6cb 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -229,8 +229,9 @@ void *qemu_memalign(size_t alignment, size_t size) /* alloc shared memory pages */ void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared) { + const uint32_t qemu_map_flags = shared ? QEMU_MAP_SHARED : 0; size_t align = QEMU_VMALLOC_ALIGN; - void *ptr = qemu_ram_mmap(-1, size, align, false, shared, false, 0); + void *ptr = qemu_ram_mmap(-1, size, align, qemu_map_flags, 0); if (ptr == MAP_FAILED) { return NULL;