From patchwork Thu Feb 2 22:56:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 13126800 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 067F6C05027 for ; Thu, 2 Feb 2023 22:57:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNiVD-0000uQ-I2; Thu, 02 Feb 2023 17:56:23 -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 1pNiVA-0000pX-R6 for qemu-devel@nongnu.org; Thu, 02 Feb 2023 17:56:21 -0500 Received: from smtp-fw-80007.amazon.com ([99.78.197.218]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNiV7-0005nl-TG for qemu-devel@nongnu.org; Thu, 02 Feb 2023 17:56:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1675378578; x=1706914578; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=mbVrwpUyO3CVy3+BtGgMlMhdgUsqTZ07GVSHXz1vros=; b=HS/yPBEBCzqgKsQeEdUfeliX/dPP77+bfO25B7rSj1SeIgQMmdJoNCLm 4GLja9a868sk36dszj9v5mCrKvnS5OxWfq/wfRi72iA/skbMMJoQkcZir Wz3F3l73gfks7LIjlo9t1QEIqQbe3Zcr3tStMXWTJQZjYL5MYiq9lGydT s=; X-IronPort-AV: E=Sophos;i="5.97,268,1669075200"; d="scan'208";a="177927177" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-iad-1e-m6i4x-7dc0ecf1.us-east-1.amazon.com) ([10.25.36.214]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Feb 2023 22:56:11 +0000 Received: from EX13MTAUWC001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-iad-1e-m6i4x-7dc0ecf1.us-east-1.amazon.com (Postfix) with ESMTPS id 5214182740; Thu, 2 Feb 2023 22:56:07 +0000 (UTC) Received: from EX19D020UWC004.ant.amazon.com (10.13.138.149) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1497.45; Thu, 2 Feb 2023 22:56:06 +0000 Received: from dev-dsk-graf-1a-5ce218e4.eu-west-1.amazon.com (10.43.160.120) by EX19D020UWC004.ant.amazon.com (10.13.138.149) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1118.24; Thu, 2 Feb 2023 22:56:04 +0000 From: Alexander Graf To: CC: Eduardo Habkost , "Daniel P . Berrange" , Markus Armbruster , Eric Blake , Philippe Mathieu-Daude , Peter Xu , Paolo Bonzini , Igor Mammedov , David Hildenbrand , Stefan Hajnoczi , Ashish Kalra Subject: [PATCH] hostmem-file: add offset option Date: Thu, 2 Feb 2023 22:56:03 +0000 Message-ID: <20230202225603.27559-1-graf@amazon.com> X-Mailer: git-send-email 2.38.1 MIME-Version: 1.0 X-Originating-IP: [10.43.160.120] X-ClientProxiedBy: EX13D39UWA002.ant.amazon.com (10.43.160.20) To EX19D020UWC004.ant.amazon.com (10.13.138.149) Precedence: Bulk Received-SPF: pass client-ip=99.78.197.218; envelope-from=prvs=3906e7c96=graf@amazon.de; helo=smtp-fw-80007.amazon.com X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 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, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_MED=-2.3, 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 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Add an option for hostmem-file to start the memory object at an offset into the target file. This is useful if multiple memory objects reside inside the same target file, such as a device node. In particular, it's useful to map guest memory directly into /dev/mem for experimentation. Signed-off-by: Alexander Graf --- backends/hostmem-file.c | 40 +++++++++++++++++++++++++++++++++++++++- include/exec/memory.h | 2 ++ include/exec/ram_addr.h | 3 ++- qapi/qom.json | 1 + qemu-options.hx | 6 +++++- softmmu/memory.c | 3 ++- softmmu/physmem.c | 5 +++-- 7 files changed, 54 insertions(+), 6 deletions(-) diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index 25141283c4..38ea65bec5 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -27,6 +27,7 @@ struct HostMemoryBackendFile { char *mem_path; uint64_t align; + uint64_t offset; bool discard_data; bool is_pmem; bool readonly; @@ -58,7 +59,8 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) ram_flags |= fb->is_pmem ? RAM_PMEM : 0; memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, backend->size, fb->align, ram_flags, - fb->mem_path, fb->readonly, errp); + fb->mem_path, fb->offset, fb->readonly, + errp); g_free(name); #endif } @@ -125,6 +127,36 @@ static void file_memory_backend_set_align(Object *o, Visitor *v, fb->align = val; } +static void file_memory_backend_get_offset(Object *o, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); + uint64_t val = fb->offset; + + visit_type_size(v, name, &val, errp); +} + +static void file_memory_backend_set_offset(Object *o, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + HostMemoryBackend *backend = MEMORY_BACKEND(o); + HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); + uint64_t val; + + if (host_memory_backend_mr_inited(backend)) { + error_setg(errp, "cannot change property '%s' of %s", name, + object_get_typename(o)); + return; + } + + if (!visit_type_size(v, name, &val, errp)) { + return; + } + fb->offset = val; +} + #ifdef CONFIG_LIBPMEM static bool file_memory_backend_get_pmem(Object *o, Error **errp) { @@ -197,6 +229,12 @@ file_backend_class_init(ObjectClass *oc, void *data) file_memory_backend_get_align, file_memory_backend_set_align, NULL, NULL); + object_class_property_add(oc, "offset", "int", + file_memory_backend_get_offset, + file_memory_backend_set_offset, + NULL, NULL); + object_class_property_set_description(oc, "offset", + "Offset into the target file (ex: 1G)"); #ifdef CONFIG_LIBPMEM object_class_property_add_bool(oc, "pmem", file_memory_backend_get_pmem, file_memory_backend_set_pmem); diff --git a/include/exec/memory.h b/include/exec/memory.h index 2e602a2fad..bd67198111 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1318,6 +1318,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM, * RAM_NORESERVE, * @path: the path in which to allocate the RAM. + * @offset: offset within the file referenced by path * @readonly: true to open @path for reading, false for read/write. * @errp: pointer to Error*, to store an error if it happens. * @@ -1331,6 +1332,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, uint64_t align, uint32_t ram_flags, const char *path, + ram_addr_t offset, bool readonly, Error **errp); diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index f4fb6a2111..90a8269290 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -110,6 +110,7 @@ long qemu_maxrampagesize(void); * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM, * RAM_NORESERVE. * @mem_path or @fd: specify the backing file or device + * @offset: Offset into target file * @readonly: true to open @path for reading, false for read/write. * @errp: pointer to Error*, to store an error if it happens * @@ -119,7 +120,7 @@ long qemu_maxrampagesize(void); */ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, const char *mem_path, - bool readonly, Error **errp); + off_t offset, bool readonly, Error **errp); RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, int fd, off_t offset, bool readonly, Error **errp); diff --git a/qapi/qom.json b/qapi/qom.json index 30e76653ad..d4e16c57a3 100644 --- a/qapi/qom.json +++ b/qapi/qom.json @@ -649,6 +649,7 @@ { 'struct': 'MemoryBackendFileProperties', 'base': 'MemoryBackendProperties', 'data': { '*align': 'size', + '*offset': 'size', '*discard-data': 'bool', 'mem-path': 'str', '*pmem': { 'type': 'bool', 'if': 'CONFIG_LIBPMEM' }, diff --git a/qemu-options.hx b/qemu-options.hx index d59d19704b..2f12a9299e 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4875,7 +4875,7 @@ SRST they are specified. Note that the 'id' property must be set. These objects are placed in the '/objects' path. - ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off`` + ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,offset=offset,readonly=on|off`` Creates a memory file backend object, which can be used to back the guest RAM with huge pages. @@ -4945,6 +4945,10 @@ SRST such cases, users can specify the required alignment via this option. + The ``offset`` option specifies the offset into the target file + that the region starts at. You can use this parameter to overload + multiple regions into a single file. + The ``pmem`` option specifies whether the backing file specified by ``mem-path`` is in host persistent memory that can be accessed using the SNIA NVM programming model (e.g. Intel diff --git a/softmmu/memory.c b/softmmu/memory.c index 9d64efca26..c9bdebcdf4 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -1601,6 +1601,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, uint64_t align, uint32_t ram_flags, const char *path, + ram_addr_t offset, bool readonly, Error **errp) { @@ -1612,7 +1613,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, mr->destructor = memory_region_destructor_ram; mr->align = align; mr->ram_block = qemu_ram_alloc_from_file(size, mr, ram_flags, path, - readonly, &err); + offset, readonly, &err); if (err) { mr->size = int128_zero(); object_unparent(OBJECT(mr)); diff --git a/softmmu/physmem.c b/softmmu/physmem.c index cb998cdf23..d5a6a0553f 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -2114,7 +2114,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, const char *mem_path, - bool readonly, Error **errp) + off_t offset, bool readonly, Error **errp) { int fd; bool created; @@ -2126,7 +2126,8 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, return NULL; } - block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, readonly, errp); + block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, offset, readonly, + errp); if (!block) { if (created) { unlink(mem_path);