From patchwork Fri May 13 14:23:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 572938 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 E6F84C433F5 for ; Fri, 13 May 2022 14:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244373AbiEMO11 (ORCPT ); Fri, 13 May 2022 10:27:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381097AbiEMO0c (ORCPT ); Fri, 13 May 2022 10:26:32 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF858506EC; Fri, 13 May 2022 07:26:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4C3F16219D; Fri, 13 May 2022 14:26:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B8DAC36AEC; Fri, 13 May 2022 14:26:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451988; bh=85U1WWVkHeMQrJWMsxOyN59skP9tpj5MeWFM5A12uXE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z69z3oDXPD21rNW9i5pU2xdBQSPQGAePhxjHL1MhlizvNubIkg2KtoA/5NPLc35nb WRkITwqgnicSG/5sBtZg7Vm2LyEr3KCNf86g+8MC7GZbp5HhpQMlVmZixtDqTet+1D sspSucBEntU5Btet39kQCTflWgfYlUUZ4zmPy+Vg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Masami Hiramatsu , Juergen Gross , x86@kernel.org, Ingo Molnar , Boris Ostrovsky , Andrew Cooper , Stefano Stabellini , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Josh Poimboeuf , Maximilian Heyne Subject: [PATCH 5.4 11/18] x86: xen: kvm: Gather the definition of emulate prefixes Date: Fri, 13 May 2022 16:23:37 +0200 Message-Id: <20220513142229.483992618@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 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 Signed-off-by: Greg Kroah-Hartman --- 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 --- /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 --- 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 */ --- 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_s 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; }