From nobody Tue Nov 18 18:25:06 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1612294371; cv=none; d=zohomail.com; s=zohoarc; b=aosJqsXNN8LMV3IBXcdk5JtN88t9igqZNGNE3XG2Z0vmB0siuE5IgBf5xeIWr/G731/A66qQ6TEJ/nx4clqpxZOir1SYgKNJ6SW0xT00/jXcbFl68XA24+NJzQAJTSE4mvPm/E+noTS5i33P6+UcKr3rW/vRsVPWSSZDb4cObQ4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1612294371; 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=z59hLLCQ4rkkrK+fxH5Wh2TWFkuJh5NzDFruH+EBRy0=; b=Py5sDVS/bm+PE+MP6nWUYP16KMQIlpFyogaERiHCiJoPXp/IkakRo5NOz6Nan/Hq+S22EauFMnl6yLoUgdNHmQCd61GC895oInJHNZGibFiJFI+Y1vidIApurYzu2Qr1LdF4nD8PPdE/MhFT2UnyhJFZ5l+tjX5jVkmQ7cYnq6k= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1612294371613170.5185968183024; Tue, 2 Feb 2021 11:32:51 -0800 (PST) Received: from localhost ([::1]:47744 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l71Pu-00016A-FS for importer@patchew.org; Tue, 02 Feb 2021 14:32:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36830) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l71O8-0008It-AX for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:31:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30352) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l71O3-0001Eg-1T for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:30:58 -0500 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-489-5-nuaSpvMzCQ0YckTfpVKw-1; Tue, 02 Feb 2021 14:30:48 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E1ED4106BAF7; Tue, 2 Feb 2021 19:30:24 +0000 (UTC) Received: from localhost (ovpn-3-197.rdu2.redhat.com [10.22.3.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id B916A7B150; Tue, 2 Feb 2021 19:30:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612294253; 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=z59hLLCQ4rkkrK+fxH5Wh2TWFkuJh5NzDFruH+EBRy0=; b=VHodZPHaea9SdBSJGXCFygCqVBJxu8N9y4EcSP9xv/3eLTQZwx3rEKlZCoG88j8Cf7rAO8 PRjFEUj71J3rVO7vKfFPR5bgSDQ+eUX7KoVmfC4eLNGUjZaE7B7IPRqZd6XQtdGpzl6hrb eJwgd+IUYAnfpG/VmQBZyYJAQ1DXff4= X-MC-Unique: 5-nuaSpvMzCQ0YckTfpVKw-1 From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Subject: [PULL 1/3] memory: add readonly support to memory_region_init_ram_from_file() Date: Tue, 2 Feb 2021 14:30:18 -0500 Message-Id: <20210202193020.4107711-2-ehabkost@redhat.com> In-Reply-To: <20210202193020.4107711-1-ehabkost@redhat.com> References: <20210202193020.4107711-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.386, 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: Igor Mammedov , "Michael S . Tsirkin" , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Stefan Hajnoczi There is currently no way to open(O_RDONLY) and mmap(PROT_READ) when creating a memory region from a file. This functionality is needed since the underlying host file may not allow writing. Add a bool readonly argument to memory_region_init_ram_from_file() and the APIs it calls. Extend memory_region_init_ram_from_file() rather than introducing a memory_region_init_rom_from_file() API so that callers can easily make a choice between read/write and read-only at runtime without calling different APIs. No new RAMBlock flag is introduced for read-only because it's unclear whether RAMBlocks need to know that they are read-only. Pass a bool readonly argument instead. Both of these design decisions can be changed in the future. It just seemed like the simplest approach to me. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Igor Mammedov Reviewed-by: Liam Merwick Acked-by: Michael S. Tsirkin Message-Id: <20210104171320.575838-2-stefanha@redhat.com> Signed-off-by: Eduardo Habkost --- include/exec/memory.h | 2 ++ include/exec/ram_addr.h | 5 +++-- include/qemu/mmap-alloc.h | 2 ++ backends/hostmem-file.c | 2 +- softmmu/memory.c | 7 +++++-- softmmu/physmem.c | 18 +++++++++++------- util/mmap-alloc.c | 10 ++++++---- util/oslib-posix.c | 2 +- 8 files changed, 31 insertions(+), 17 deletions(-) diff --git a/include/exec/memory.h b/include/exec/memory.h index 521d9901d7c..c6ce74fb790 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -966,6 +966,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, * - RAM_PMEM: the memory is persistent memory * Other bits are ignored now. * @path: the path in which to allocate the RAM. + * @readonly: true to open @path for reading, false for read/write. * @errp: pointer to Error*, to store an error if it happens. * * Note that this function does not do anything to cause the data in the @@ -978,6 +979,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, uint64_t align, uint32_t ram_flags, const char *path, + bool readonly, Error **errp); =20 /** diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index c6d2ef1d07e..40b16609abc 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -110,6 +110,7 @@ long qemu_maxrampagesize(void); * - RAM_PMEM: the backend @mem_path or @fd is persistent mem= ory * Other bits are ignored. * @mem_path or @fd: specify the backing file or device + * @readonly: true to open @path for reading, false for read/write. * @errp: pointer to Error*, to store an error if it happens * * Return: @@ -118,9 +119,9 @@ long qemu_maxrampagesize(void); */ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, const char *mem_pat= h, - Error **errp); + bool readonly, Error **errp); RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, - uint32_t ram_flags, int fd, + uint32_t ram_flags, int fd, bool readonly, Error **errp); =20 RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h index e786266b923..8b7a5c70f37 100644 --- a/include/qemu/mmap-alloc.h +++ b/include/qemu/mmap-alloc.h @@ -14,6 +14,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path); * @size: the number of bytes to be mmaped * @align: if not zero, specify the alignment of the starting mapping add= ress; * 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. * @@ -24,6 +25,7 @@ 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); =20 diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index 40e1e5b3e3b..e8276921244 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -56,7 +56,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Err= or **errp) backend->size, fb->align, (backend->share ? RAM_SHARED : 0) | (fb->is_pmem ? RAM_PMEM : 0), - fb->mem_path, errp); + fb->mem_path, false, errp); g_free(name); #endif } diff --git a/softmmu/memory.c b/softmmu/memory.c index 333e1ed7b05..676c298b606 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -1587,15 +1587,18 @@ void memory_region_init_ram_from_file(MemoryRegion = *mr, uint64_t align, uint32_t ram_flags, const char *path, + bool readonly, Error **errp) { Error *err =3D NULL; memory_region_init(mr, owner, name, size); mr->ram =3D true; + mr->readonly =3D readonly; mr->terminates =3D true; mr->destructor =3D memory_region_destructor_ram; mr->align =3D align; - mr->ram_block =3D qemu_ram_alloc_from_file(size, mr, ram_flags, path, = &err); + mr->ram_block =3D qemu_ram_alloc_from_file(size, mr, ram_flags, path, + readonly, &err); if (err) { mr->size =3D int128_zero(); object_unparent(OBJECT(mr)); @@ -1618,7 +1621,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr, mr->destructor =3D memory_region_destructor_ram; mr->ram_block =3D qemu_ram_alloc_from_fd(size, mr, share ? RAM_SHARED : 0, - fd, &err); + fd, false, &err); if (err) { mr->size =3D int128_zero(); object_unparent(OBJECT(mr)); diff --git a/softmmu/physmem.c b/softmmu/physmem.c index cdcd197656f..60760a3bdc5 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -1398,6 +1398,7 @@ static int64_t get_file_align(int fd) =20 static int file_ram_open(const char *path, const char *region_name, + bool readonly, bool *created, Error **errp) { @@ -1408,7 +1409,7 @@ static int file_ram_open(const char *path, =20 *created =3D false; for (;;) { - fd =3D open(path, O_RDWR); + fd =3D open(path, readonly ? O_RDONLY : O_RDWR); if (fd >=3D 0) { /* @path names an existing file, use it */ break; @@ -1460,6 +1461,7 @@ static int file_ram_open(const char *path, static void *file_ram_alloc(RAMBlock *block, ram_addr_t memory, int fd, + bool readonly, bool truncate, Error **errp) { @@ -1510,7 +1512,7 @@ static void *file_ram_alloc(RAMBlock *block, perror("ftruncate"); } =20 - area =3D qemu_ram_mmap(fd, memory, block->mr->align, + area =3D qemu_ram_mmap(fd, memory, block->mr->align, readonly, block->flags & RAM_SHARED, block->flags & RAM_PME= M); if (area =3D=3D MAP_FAILED) { error_setg_errno(errp, errno, @@ -1942,7 +1944,7 @@ static void ram_block_add(RAMBlock *new_block, Error = **errp, bool shared) =20 #ifdef CONFIG_POSIX RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, - uint32_t ram_flags, int fd, + uint32_t ram_flags, int fd, bool readonly, Error **errp) { RAMBlock *new_block; @@ -1996,7 +1998,8 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, Mem= oryRegion *mr, new_block->used_length =3D size; new_block->max_length =3D size; new_block->flags =3D ram_flags; - new_block->host =3D file_ram_alloc(new_block, size, fd, !file_size, er= rp); + new_block->host =3D file_ram_alloc(new_block, size, fd, readonly, + !file_size, errp); if (!new_block->host) { g_free(new_block); return NULL; @@ -2015,18 +2018,19 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, M= emoryRegion *mr, =20 RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, const char *mem_pat= h, - Error **errp) + bool readonly, Error **errp) { int fd; bool created; RAMBlock *block; =20 - fd =3D file_ram_open(mem_path, memory_region_name(mr), &created, errp); + fd =3D file_ram_open(mem_path, memory_region_name(mr), readonly, &crea= ted, + errp); if (fd < 0) { return NULL; } =20 - block =3D qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp); + block =3D qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, readonly, er= rp); if (!block) { if (created) { unlink(mem_path); diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 27dcccd8ec8..890fda6a354 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -85,9 +85,11 @@ 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) { + int prot; int flags; int map_sync_flags =3D 0; int guardfd; @@ -146,8 +148,9 @@ void *qemu_ram_mmap(int fd, =20 offset =3D QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guar= dptr; =20 - ptr =3D mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, - flags | map_sync_flags, fd, 0); + prot =3D PROT_READ | (readonly ? 0 : PROT_WRITE); + + ptr =3D mmap(guardptr + offset, size, prot, flags | map_sync_flags, fd= , 0); =20 if (ptr =3D=3D MAP_FAILED && map_sync_flags) { if (errno =3D=3D ENOTSUP) { @@ -171,8 +174,7 @@ void *qemu_ram_mmap(int fd, * if map failed with MAP_SHARED_VALIDATE | MAP_SYNC, * we will remove these flags to handle compatibility. */ - ptr =3D mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, - flags, fd, 0); + ptr =3D mmap(guardptr + offset, size, prot, flags, fd, 0); } =20 if (ptr =3D=3D MAP_FAILED) { diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 359c52df123..bf57d3b0307 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -230,7 +230,7 @@ void *qemu_memalign(size_t alignment, size_t size) void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared) { size_t align =3D QEMU_VMALLOC_ALIGN; - void *ptr =3D qemu_ram_mmap(-1, size, align, shared, false); + void *ptr =3D qemu_ram_mmap(-1, size, align, false, shared, false); =20 if (ptr =3D=3D MAP_FAILED) { return NULL; --=20 2.28.0 From nobody Tue Nov 18 18:25:06 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1612294442; cv=none; d=zohomail.com; s=zohoarc; b=K56gSOsVpKQP5kwiDxwQN9cS7/aaC4R05j0+NywLuLglQA7WgjKXhCbKk4lyeD3RuysvMFFT95fqfOb5y6/CCEZJHzz02v0oaDB6cTIGS2+PeoEbjk6lJOXYX0riO06hy1bvQsgElF2+ADo+WZX3yhkGdSwbrzTiRSpQKq5G0RE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1612294442; 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=aGiRvX/miiDra234/3N3CmVjK/lJzDKYceY/6z9WJE8=; b=Y1cwx5JRuVf4pB7jSQgpwK9yee5od4wasniIQ1STuNoJoNjycXY5RDZTEiga56No8LK5373QFfuq7IO4rJCfAb9TniJuN4IiIqAiavjg0aGLMx6+NAn3UTlGYobLSOrLPr9CsV3tuJI50/3/s4il29Ze1G5nnYOoa4XBNweWZdk= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1612294442009906.1708228461673; Tue, 2 Feb 2021 11:34:02 -0800 (PST) Received: from localhost ([::1]:52692 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l71R2-00037G-S0 for importer@patchew.org; Tue, 02 Feb 2021 14:34:00 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36846) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l71O9-0008J9-Nx for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:31:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:55321) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l71O7-0001Fs-8y for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:31:01 -0500 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-56-wdoEUUNeNSGxKnGM6sCnUA-1; Tue, 02 Feb 2021 14:30:54 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3AF07C7432; Tue, 2 Feb 2021 19:30:25 +0000 (UTC) Received: from localhost (ovpn-3-197.rdu2.redhat.com [10.22.3.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id 014106EF57; Tue, 2 Feb 2021 19:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612294257; 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=aGiRvX/miiDra234/3N3CmVjK/lJzDKYceY/6z9WJE8=; b=CVdKox/ZS7qRepxacCRNnykoHd9RouUKOUDHL8jrc/CBpy3Tj0QF6sXkb8oHLEK/D05rUd PW8bydgUK0nK/jD7XiDdbQ9iRkVBcOeizDerDB/HdbOGg+6jwOsrnhV2brYzzaI+REBE8Q 4MtQNSzABFyXnyLm623luvm3aZg9g5A= X-MC-Unique: wdoEUUNeNSGxKnGM6sCnUA-1 From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Subject: [PULL 2/3] hostmem-file: add readonly=on|off option Date: Tue, 2 Feb 2021 14:30:19 -0500 Message-Id: <20210202193020.4107711-3-ehabkost@redhat.com> In-Reply-To: <20210202193020.4107711-1-ehabkost@redhat.com> References: <20210202193020.4107711-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.386, 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_H4=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: Igor Mammedov , "Michael S . Tsirkin" , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Stefan Hajnoczi Let -object memory-backend-file work on read-only files when the readonly=3Don option is given. This can be used to share the contents of a file between multiple guests while preventing them from consuming Copy-on-Write memory if guests dirty the pages, for example. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Liam Merwick Acked-by: Michael S. Tsirkin Message-Id: <20210104171320.575838-3-stefanha@redhat.com> Signed-off-by: Eduardo Habkost --- backends/hostmem-file.c | 28 +++++++++++++++++++++++++++- qemu-options.hx | 5 ++++- 2 files changed, 31 insertions(+), 2 deletions(-) diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index e8276921244..733408e076f 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -29,6 +29,7 @@ struct HostMemoryBackendFile { uint64_t align; bool discard_data; bool is_pmem; + bool readonly; }; =20 static void @@ -56,7 +57,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Err= or **errp) backend->size, fb->align, (backend->share ? RAM_SHARED : 0) | (fb->is_pmem ? RAM_PMEM : 0), - fb->mem_path, false, errp); + fb->mem_path, fb->readonly, errp); g_free(name); #endif } @@ -151,6 +152,28 @@ static void file_memory_backend_set_pmem(Object *o, bo= ol value, Error **errp) fb->is_pmem =3D value; } =20 +static bool file_memory_backend_get_readonly(Object *obj, Error **errp) +{ + HostMemoryBackendFile *fb =3D MEMORY_BACKEND_FILE(obj); + + return fb->readonly; +} + +static void file_memory_backend_set_readonly(Object *obj, bool value, + Error **errp) +{ + HostMemoryBackend *backend =3D MEMORY_BACKEND(obj); + HostMemoryBackendFile *fb =3D MEMORY_BACKEND_FILE(obj); + + if (host_memory_backend_mr_inited(backend)) { + error_setg(errp, "cannot change property 'readonly' of %s.", + object_get_typename(obj)); + return; + } + + fb->readonly =3D value; +} + static void file_backend_unparent(Object *obj) { HostMemoryBackend *backend =3D MEMORY_BACKEND(obj); @@ -182,6 +205,9 @@ file_backend_class_init(ObjectClass *oc, void *data) NULL, NULL); object_class_property_add_bool(oc, "pmem", file_memory_backend_get_pmem, file_memory_backend_set_pmem); + object_class_property_add_bool(oc, "readonly", + file_memory_backend_get_readonly, + file_memory_backend_set_readonly); } =20 static void file_backend_instance_finalize(Object *o) diff --git a/qemu-options.hx b/qemu-options.hx index d0410f05125..c09c4646e28 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4426,7 +4426,7 @@ SRST they are specified. Note that the 'id' property must be set. These objects are placed in the '/objects' path. =20 - ``-object memory-backend-file,id=3Did,size=3Dsize,mem-path=3Ddir,share= =3Don|off,discard-data=3Don|off,merge=3Don|off,dump=3Don|off,prealloc=3Don|= off,host-nodes=3Dhost-nodes,policy=3Ddefault|preferred|bind|interleave,alig= n=3Dalign`` + ``-object memory-backend-file,id=3Did,size=3Dsize,mem-path=3Ddir,share= =3Don|off,discard-data=3Don|off,merge=3Don|off,dump=3Don|off,prealloc=3Don|= off,host-nodes=3Dhost-nodes,policy=3Ddefault|preferred|bind|interleave,alig= n=3Dalign,readonly=3Don|off`` Creates a memory file backend object, which can be used to back the guest RAM with huge pages. =20 @@ -4509,6 +4509,9 @@ SRST 4.15) and the filesystem of ``mem-path`` mounted with DAX option. =20 + The ``readonly`` option specifies whether the backing file is open= ed + read-only or read-write (default). + ``-object memory-backend-ram,id=3Did,merge=3Don|off,dump=3Don|off,shar= e=3Don|off,prealloc=3Don|off,size=3Dsize,host-nodes=3Dhost-nodes,policy=3Dd= efault|preferred|bind|interleave`` Creates a memory backend object, which can be used to back the guest RAM. Memory backend objects offer more control than the --=20 2.28.0 From nobody Tue Nov 18 18:25:06 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1612294378; cv=none; d=zohomail.com; s=zohoarc; b=c+mMINenT+0Y1LzeMTxvtUg97QNYIcUJ0mPCTFCPyImG3xzXO/qfas4lNaOuLXfSadj0X2ugi+Q5cv2IeTBnw5Mr7EmsQYAmDU61EbVtKuv3fArxjjuzFVG6N1abPOsdXnFhcFtX++YHMmGqB92jx8N/+KuWKur57iy4mmVlYpI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1612294378; 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=ji6KeukqbRf7zODdJI6lHJJTAz5NSV5XkIwI85m3pt4=; b=SYDjyZK7GTwtQECrvDn/0knzgK2hRNFjOyi6WINm3Ro3bR8iHUCPsCbUEibcqQq1abNrdvVeTCgJJVusnqUjquguE6KLWKW5cfqMMzOHXbhTutoN9SwIYuLdF1cl5JzQ+fevC5LYvNuGzVds/IMZXgM3I/l0rJaN/zzy7jc5jpk= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1612294378335398.7163774661268; Tue, 2 Feb 2021 11:32:58 -0800 (PST) Received: from localhost ([::1]:48454 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l71Q1-0001ON-77 for importer@patchew.org; Tue, 02 Feb 2021 14:32:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36900) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l71OG-0008Sy-SA for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:31:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:41805) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l71OE-0001Iu-Vb for qemu-devel@nongnu.org; Tue, 02 Feb 2021 14:31:08 -0500 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-310-nxIsz9zMP6GTyFYNLWm2Dw-1; Tue, 02 Feb 2021 14:30:55 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 083DA1084D61; Tue, 2 Feb 2021 19:30:26 +0000 (UTC) Received: from localhost (ovpn-3-197.rdu2.redhat.com [10.22.3.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id C3B1350B44; Tue, 2 Feb 2021 19:30:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612294266; 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=ji6KeukqbRf7zODdJI6lHJJTAz5NSV5XkIwI85m3pt4=; b=Ma1E28rzJvydaieiEmH34czMD1KTX5VJxe7P0W21X95MqMTn37pXGnqMS0ibbn99aDPjT2 FYIZNth13migQhJpVEoMZdseKXupp62rhBL/1yzYJ0QeUunzpqFSqr1JKsMsewVAP6728I QbjdM820iJnAmUtJCnxcEeqOYViUS5A= X-MC-Unique: nxIsz9zMP6GTyFYNLWm2Dw-1 From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Subject: [PULL 3/3] nvdimm: check -object memory-backend-file, readonly=on option Date: Tue, 2 Feb 2021 14:30:20 -0500 Message-Id: <20210202193020.4107711-4-ehabkost@redhat.com> In-Reply-To: <20210202193020.4107711-1-ehabkost@redhat.com> References: <20210202193020.4107711-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=ehabkost@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.386, 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_H4=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: Igor Mammedov , "Michael S . Tsirkin" , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Stefan Hajnoczi Check that -device nvdimm,unarmed=3Don is used when -object memory-backend-file,readonly=3Don and document that -device nvdimm,unarmed=3Don|off controls whether the NVDIMM appears read-only to the guest. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Liam Merwick Acked-by: Michael S. Tsirkin Message-Id: <20210104171320.575838-4-stefanha@redhat.com> Signed-off-by: Eduardo Habkost --- docs/nvdimm.txt | 24 +++++++++++++++++------- hw/mem/nvdimm.c | 9 +++++++++ 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt index c2c6e441b34..0aae682be3e 100644 --- a/docs/nvdimm.txt +++ b/docs/nvdimm.txt @@ -17,8 +17,8 @@ following command line options: =20 -machine pc,nvdimm -m $RAM_SIZE,slots=3D$N,maxmem=3D$MAX_SIZE - -object memory-backend-file,id=3Dmem1,share=3Don,mem-path=3D$PATH,size=3D= $NVDIMM_SIZE - -device nvdimm,id=3Dnvdimm1,memdev=3Dmem1 + -object memory-backend-file,id=3Dmem1,share=3Don,mem-path=3D$PATH,size=3D= $NVDIMM_SIZE,readonly=3Doff + -device nvdimm,id=3Dnvdimm1,memdev=3Dmem1,unarmed=3Doff =20 Where, =20 @@ -31,9 +31,10 @@ Where, of normal RAM devices and vNVDIMM devices, e.g. $MAX_SIZE should be >=3D $RAM_SIZE + $NVDIMM_SIZE here. =20 - - "object memory-backend-file,id=3Dmem1,share=3Don,mem-path=3D$PATH,size= =3D$NVDIMM_SIZE" - creates a backend storage of size $NVDIMM_SIZE on a file $PATH. All - accesses to the virtual NVDIMM device go to the file $PATH. + - "object memory-backend-file,id=3Dmem1,share=3Don,mem-path=3D$PATH, + size=3D$NVDIMM_SIZE,readonly=3Doff" creates a backend storage of size + $NVDIMM_SIZE on a file $PATH. All accesses to the virtual NVDIMM device= go + to the file $PATH. =20 "share=3Don/off" controls the visibility of guest writes. If "share=3Don", then guest writes will be applied to the backend @@ -42,8 +43,17 @@ Where, "share=3Doff", then guest writes won't be applied to the backend file and thus will be invisible to other guests. =20 - - "device nvdimm,id=3Dnvdimm1,memdev=3Dmem1" creates a virtual NVDIMM - device whose storage is provided by above memory backend device. + "readonly=3Don/off" controls whether the file $PATH is opened read-only= or + read/write (default). + + - "device nvdimm,id=3Dnvdimm1,memdev=3Dmem1,unarmed=3Doff" creates a read= /write + virtual NVDIMM device whose storage is provided by above memory backend + device. + + "unarmed" controls the ACPI NFIT NVDIMM Region Mapping Structure "NVDIMM + State Flags" Bit 3 indicating that the device is "unarmed" and cannot a= ccept + persistent writes. Linux guest drivers set the device to read-only when= this + bit is present. Set unarmed to on when the memdev has readonly=3Don. =20 Multiple vNVDIMM devices can be created if multiple pairs of "-object" and "-device" are provided. diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c index 03c2201b564..e0a9d606e1b 100644 --- a/hw/mem/nvdimm.c +++ b/hw/mem/nvdimm.c @@ -146,6 +146,15 @@ static void nvdimm_prepare_memory_region(NVDIMMDevice = *nvdimm, Error **errp) return; } =20 + if (!nvdimm->unarmed && memory_region_is_rom(mr)) { + HostMemoryBackend *hostmem =3D dimm->hostmem; + + error_setg(errp, "'unarmed' property must be off since memdev %s " + "is read-only", + object_get_canonical_path_component(OBJECT(hostmem))); + return; + } + nvdimm->nvdimm_mr =3D g_new(MemoryRegion, 1); memory_region_init_alias(nvdimm->nvdimm_mr, OBJECT(dimm), "nvdimm-memory", mr, 0, pmem_size); --=20 2.28.0