From patchwork Fri Sep 27 07:19:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 13813961 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 85C24CEBF7E for ; Fri, 27 Sep 2024 07:20:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1su5Gw-0007gp-BY; Fri, 27 Sep 2024 03:20:14 -0400 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 <3n1z2ZggKCnAOfRP+UWhUccUZS.QcaeSai-RSjSZbcbUbi.cfU@flex--ardb.bounces.google.com>) id 1su5Gp-0007eB-FV for qemu-devel@nongnu.org; Fri, 27 Sep 2024 03:20:07 -0400 Received: from mail-yw1-x114a.google.com ([2607:f8b0:4864:20::114a]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from <3n1z2ZggKCnAOfRP+UWhUccUZS.QcaeSai-RSjSZbcbUbi.cfU@flex--ardb.bounces.google.com>) id 1su5Gm-0002ps-OE for qemu-devel@nongnu.org; Fri, 27 Sep 2024 03:20:07 -0400 Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-6e22f0be237so34198537b3.1 for ; Fri, 27 Sep 2024 00:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727421599; x=1728026399; darn=nongnu.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=OgGxdzkwhJAJ9NOcliVi3NgTrAWOMCFFcr8qpMg1A1c=; b=XVRWqBzAl6qtm+cenLEdnJvqxQvwRpSnrCLIu//mUaBj8zLl/OGQAfW3oOx6ZW0NyO OHl7rcYTdIb+ymHWjeC6W1az8P+yBkPellTuHO8CcnKqsrzawtSJdPZhcPe9fec3f0nO yE6ufUQFAq+y1yVCoxYiK75gOkipiQO2+4c+CMx5QLvbNH9lZzJztZEDB+FiubtsCIDV evrqSPA3mbRuGPzfRtPQkEvL2CBYyuZm0aMmnfmcfUMeElI/pYtk0iFgGn7YL2HuAjNJ tY9GRMSNIQ1cdew91feFDru0GzuGb0OKVscBcDTxuEWBJ8FcZWAPVOUqSdGGZS0qyc2q xhvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727421599; x=1728026399; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=OgGxdzkwhJAJ9NOcliVi3NgTrAWOMCFFcr8qpMg1A1c=; b=fIX6B8nWXiXTEICDpLIFTM2RzecZloovcmXQUSKmsoz+FplQenRe8g5N+FPp+eDCWv VUTsjB2gfpbvBCeu6F9lcyerZUxVnXQM7WyHBuxUmtY3BXeQNvbXZjpe7lZNt35d1+ak V5+RLwTlk3tQEp/Uh++bG9OEp+46tgAWvjbh1pzw+o7cNiaTuDF8peWtGVQ0DdZDEsmA K5nUrDIGQIO+hfAM9N6okaiWa+bcIlcP7hra+CPrJO3ge6PDV3oGMrzr3GC/twFTk7ev fULRgRmwYcaRJQqwBGU+5jb3FIU9udVCp8m9Qzh1N2wlTGjIHM3MeKTUMKibAkUMxHAk YYwQ== X-Gm-Message-State: AOJu0YyIRm/5phDs0Tsz2vW1HK3Ki7P40aCGzQ0mv1NTwggiD8L5vhdU 4nitEwvYiptpRLaBGXlPmTs9OZ5hk3E6afHPmQLC8ogCp/EyPDoay2ElpxtGZ2W63OLMP9cBkYu uVIHzeaEOmaqKM0LT91yBIiLhqHzLDgFgtPKtHXERZxxluzQLCQ43pyV0Y71ZEEPf16sq8wrj4B 3QEy6rt3UvLKVQH9QT61AK X-Google-Smtp-Source: AGHT+IHt5/itZDbIJJU5kYUykfmy2GrI+eHJFLYr01f3D/51Rl7ocNh3AA3MsbPuJXtLza8p7BgMSo3T X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a05:690c:c83:b0:68d:52a1:bed with SMTP id 00721157ae682-6e2474d2257mr710357b3.1.1727421599325; Fri, 27 Sep 2024 00:19:59 -0700 (PDT) Date: Fri, 27 Sep 2024 09:19:50 +0200 Mime-Version: 1.0 X-Mailer: git-send-email 2.46.1.824.gd892dcdcdd-goog Message-ID: <20240927071950.1458596-1-ardb+git@google.com> Subject: [PATCH] hw/x86: Always treat the PVH entrypoint as a 32-bit field From: Ard Biesheuvel To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, Ard Biesheuvel Received-SPF: pass client-ip=2607:f8b0:4864:20::114a; envelope-from=3n1z2ZggKCnAOfRP+UWhUccUZS.QcaeSai-RSjSZbcbUbi.cfU@flex--ardb.bounces.google.com; helo=mail-yw1-x114a.google.com X-Spam_score_int: -95 X-Spam_score: -9.6 X-Spam_bar: --------- X-Spam_report: (-9.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5 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: Ard Biesheuvel The PVH entrypoint is entered in 32-bit mode, and is documented as being a 32-bit field. Linux happens to widen the field in the ELF note to 64 bits so treating it as a 64-bit field works for booting the kernel. However, Xen documents the ELF note with the following example ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY, .long, xen_start32) and uses .long in the code as well, and so reading more than 32 bits here is risky. And dereferencing a size_t* in portable code is just bizarre, so let's use a uint32_t specifically in all cases here. Signed-off-by: Ard Biesheuvel --- hw/i386/x86-common.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c index 992ea1f25e..5b1971c13b 100644 --- a/hw/i386/x86-common.c +++ b/hw/i386/x86-common.c @@ -539,7 +539,7 @@ DeviceState *ioapic_init_secondary(GSIState *gsi_state) */ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, bool is64) { - size_t *elf_note_data_addr; + void *elf_note_data_addr; /* Check if ELF Note header passed in is valid */ if (arg1 == NULL) { @@ -555,8 +555,6 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, bool is64) elf_note_data_addr = ((void *)nhdr64) + nhdr_size64 + QEMU_ALIGN_UP(nhdr_namesz, phdr_align); - - pvh_start_addr = *elf_note_data_addr; } else { struct elf32_note *nhdr32 = (struct elf32_note *)arg1; uint32_t nhdr_size32 = sizeof(struct elf32_note); @@ -566,10 +564,10 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, bool is64) elf_note_data_addr = ((void *)nhdr32) + nhdr_size32 + QEMU_ALIGN_UP(nhdr_namesz, phdr_align); - - pvh_start_addr = *(uint32_t *)elf_note_data_addr; } + pvh_start_addr = *(uint32_t *)elf_note_data_addr; + return pvh_start_addr; }