From patchwork Fri Feb 7 09:59:47 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13964716 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 DF55CC0219C for ; Fri, 7 Feb 2025 10:02:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tgL9g-0006u8-81; Fri, 07 Feb 2025 05:00:12 -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 1tgL9e-0006qf-0V; Fri, 07 Feb 2025 05:00:10 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tgL9b-00024M-Ox; Fri, 07 Feb 2025 05:00:09 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 23BB6E7349; Fri, 07 Feb 2025 12:59:18 +0300 (MSK) Received: from gandalf.tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with ESMTP id 8D7451B09CD; Fri, 7 Feb 2025 12:59:59 +0300 (MSK) Received: by gandalf.tls.msk.ru (Postfix, from userid 1000) id 817B652D7B; Fri, 07 Feb 2025 12:59:59 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Steve Sistare , Peter Xu , David Hildenbrand , Fabiano Rosas , Michael Tokarev Subject: [Stable-9.2.1 45/49] physmem: fix qemu_ram_alloc_from_fd size calculation Date: Fri, 7 Feb 2025 12:59:47 +0300 Message-Id: <20250207095956.2238705-4-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Steve Sistare qemu_ram_alloc_from_fd allocates space if file_size == 0. If non-zero, it uses the existing space and verifies it is large enough, but the verification was broken when the offset parameter was introduced. As a result, a file smaller than offset passes the verification and causes errors later. Fix that, and update the error message to include offset. Peter provides this concise reproducer: $ touch ramfile $ truncate -s 64M ramfile $ ./qemu-system-x86_64 -object memory-backend-file,mem-path=./ramfile,offset=128M,size=128M,id=mem1,prealloc=on qemu-system-x86_64: qemu_prealloc_mem: preallocating memory failed: Bad address With the fix, the error message is: qemu-system-x86_64: mem1 backing store size 0x4000000 is too small for 'size' option 0x8000000 plus 'offset' option 0x8000000 Cc: qemu-stable@nongnu.org Fixes: 4b870dc4d0c0 ("hostmem-file: add offset option") Signed-off-by: Steve Sistare Reviewed-by: Peter Xu Acked-by: David Hildenbrand Link: https://lore.kernel.org/r/1736967650-129648-3-git-send-email-steven.sistare@oracle.com Signed-off-by: Fabiano Rosas (cherry picked from commit 719168fba7c3215cc996dcfd32a6e5e9c7b8eee0) Signed-off-by: Michael Tokarev diff --git a/system/physmem.c b/system/physmem.c index dc1db3a384..75389064a8 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -1970,10 +1970,12 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, size = REAL_HOST_PAGE_ALIGN(size); file_size = get_file_size(fd); - if (file_size > offset && file_size < (offset + size)) { - error_setg(errp, "backing store size 0x%" PRIx64 - " does not match 'size' option 0x" RAM_ADDR_FMT, - file_size, size); + if (file_size && file_size < offset + size) { + error_setg(errp, "%s backing store size 0x%" PRIx64 + " is too small for 'size' option 0x" RAM_ADDR_FMT + " plus 'offset' option 0x%" PRIx64, + memory_region_name(mr), file_size, size, + (uint64_t)offset); return NULL; }