From patchwork Thu May 12 13:56:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Heyne X-Patchwork-Id: 572064 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB5CCC433F5 for ; Thu, 12 May 2022 13:58:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354802AbiELN6J (ORCPT ); Thu, 12 May 2022 09:58:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354789AbiELN6I (ORCPT ); Thu, 12 May 2022 09:58:08 -0400 Received: from smtp-fw-6002.amazon.com (smtp-fw-6002.amazon.com [52.95.49.90]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF63F1DFD8E; Thu, 12 May 2022 06:58:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1652363887; x=1683899887; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=/jlcjyqHJJuyQxaME83nVeMauiezhLHJNpjQ1y9lQkI=; b=ljTO917BBBKazj+Rfl9IX8PBshExXoLw8KnWToVU7kCk+jV9y/WKwcQs +2dyiiSUxDaCN59U9q7vYliUOkUsZgg/pEpQdmxTP33XkQ5gAQRTfQvux CuzPvOh5L/Brk/f5vn4nrwCp08/tqFTM82JQ060FruhA4Ubdb1BAkuz7k A=; X-IronPort-AV: E=Sophos;i="5.91,220,1647302400"; d="scan'208";a="201008348" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-iad-1a-a31e1d63.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-6002.iad6.amazon.com with ESMTP; 12 May 2022 13:58:05 +0000 Received: from EX13D08EUB003.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1a-a31e1d63.us-east-1.amazon.com (Postfix) with ESMTPS id 446238942B; Thu, 12 May 2022 13:57:56 +0000 (UTC) Received: from EX13MTAUEE002.ant.amazon.com (10.43.62.24) by EX13D08EUB003.ant.amazon.com (10.43.166.117) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Thu, 12 May 2022 13:57:55 +0000 Received: from dev-dsk-mheyne-1b-c1524648.eu-west-1.amazon.com (10.15.60.66) by mail-relay.amazon.com (10.43.62.224) with Microsoft SMTP Server id 15.0.1497.32 via Frontend Transport; Thu, 12 May 2022 13:57:54 +0000 Received: by dev-dsk-mheyne-1b-c1524648.eu-west-1.amazon.com (Postfix, from userid 5466572) id 250F041131; Thu, 12 May 2022 13:57:54 +0000 (UTC) From: Maximilian Heyne To: CC: Masami Hiramatsu , Peter Zijlstra , Juergen Gross , , Ingo Molnar , Boris Ostrovsky , Andrew Cooper , Stefano Stabellini , Borislav Petkov , , Randy Dunlap , Josh Poimboeuf , Maximilian Heyne , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Sasha Levin , , Subject: [PATCH 2/4] x86: xen: kvm: Gather the definition of emulate prefixes Date: Thu, 12 May 2022 13:56:49 +0000 Message-ID: <20220512135654.119791-3-mheyne@amazon.de> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220512135654.119791-1-mheyne@amazon.de> References: <20220512135654.119791-1-mheyne@amazon.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Masami Hiramatsu commit b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 upstream Gather the emulate prefixes, which forcibly make the following instruction emulated on virtualization, in one place. Suggested-by: Peter Zijlstra Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) Cc: Juergen Gross Cc: x86@kernel.org Cc: Ingo Molnar Cc: Boris Ostrovsky Cc: Andrew Cooper Cc: Stefano Stabellini Cc: Borislav Petkov Cc: xen-devel@lists.xenproject.org Cc: Randy Dunlap Cc: Josh Poimboeuf Link: https://lkml.kernel.org/r/156777563917.25081.7286628561790289995.stgit@devnote2 Signed-off-by: Maximilian Heyne Cc: stable@vger.kernel.org # 5.4.x --- arch/x86/include/asm/emulate_prefix.h | 14 ++++++++++++++ arch/x86/include/asm/xen/interface.h | 11 ++++------- arch/x86/kvm/x86.c | 4 +++- 3 files changed, 21 insertions(+), 8 deletions(-) create mode 100644 arch/x86/include/asm/emulate_prefix.h diff --git a/arch/x86/include/asm/emulate_prefix.h b/arch/x86/include/asm/emulate_prefix.h new file mode 100644 index 000000000000..70f5b98a5286 --- /dev/null +++ b/arch/x86/include/asm/emulate_prefix.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_EMULATE_PREFIX_H +#define _ASM_X86_EMULATE_PREFIX_H + +/* + * Virt escape sequences to trigger instruction emulation; + * ideally these would decode to 'whole' instruction and not destroy + * the instruction stream; sadly this is not true for the 'kvm' one :/ + */ + +#define __XEN_EMULATE_PREFIX 0x0f,0x0b,0x78,0x65,0x6e /* ud2 ; .ascii "xen" */ +#define __KVM_EMULATE_PREFIX 0x0f,0x0b,0x6b,0x76,0x6d /* ud2 ; .ascii "kvm" */ + +#endif diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h index 62ca03ef5c65..9139b3e86316 100644 --- a/arch/x86/include/asm/xen/interface.h +++ b/arch/x86/include/asm/xen/interface.h @@ -379,12 +379,9 @@ struct xen_pmu_arch { * Prefix forces emulation of some non-trapping instructions. * Currently only CPUID. */ -#ifdef __ASSEMBLY__ -#define XEN_EMULATE_PREFIX .byte 0x0f,0x0b,0x78,0x65,0x6e ; -#define XEN_CPUID XEN_EMULATE_PREFIX cpuid -#else -#define XEN_EMULATE_PREFIX ".byte 0x0f,0x0b,0x78,0x65,0x6e ; " -#define XEN_CPUID XEN_EMULATE_PREFIX "cpuid" -#endif +#include + +#define XEN_EMULATE_PREFIX __ASM_FORM(.byte __XEN_EMULATE_PREFIX ;) +#define XEN_CPUID XEN_EMULATE_PREFIX __ASM_FORM(cpuid) #endif /* _ASM_X86_XEN_INTERFACE_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1f7dfa5aa42d..6dd77e426889 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -68,6 +68,7 @@ #include #include #include +#include #include #define CREATE_TRACE_POINTS @@ -5583,6 +5584,7 @@ EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system); int handle_ud(struct kvm_vcpu *vcpu) { + static const char kvm_emulate_prefix[] = { __KVM_EMULATE_PREFIX }; int emul_type = EMULTYPE_TRAP_UD; char sig[5]; /* ud2; .ascii "kvm" */ struct x86_exception e; @@ -5590,7 +5592,7 @@ int handle_ud(struct kvm_vcpu *vcpu) if (force_emulation_prefix && kvm_read_guest_virt(vcpu, kvm_get_linear_rip(vcpu), sig, sizeof(sig), &e) == 0 && - memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) { + memcmp(sig, kvm_emulate_prefix, sizeof(sig)) == 0) { kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig)); emul_type = EMULTYPE_TRAP_UD_FORCED; }