From patchwork Tue Mar 24 16:29:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 11455997 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8EC396CA for ; Tue, 24 Mar 2020 16:30:41 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 730362076F for ; Tue, 24 Mar 2020 16:30:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 730362076F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jGmQX-0003XL-NI; Tue, 24 Mar 2020 16:29:17 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jGmQW-0003Ws-48 for xen-devel@lists.xenproject.org; Tue, 24 Mar 2020 16:29:16 +0000 X-Inumbo-ID: 99e3203a-6dec-11ea-8476-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 99e3203a-6dec-11ea-8476-12813bfff9fa; Tue, 24 Mar 2020 16:29:15 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 86765ABF4; Tue, 24 Mar 2020 16:29:14 +0000 (UTC) From: Jan Beulich To: "xen-devel@lists.xenproject.org" , Andrew Cooper , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Wei Liu References: Message-ID: <78b62646-6fd4-e5b3-bc09-783bb017eaaa@suse.com> Date: Tue, 24 Mar 2020 17:29:13 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Subject: [Xen-devel] [PATCH 7/7] x86emul: support SYSRET X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" This is to augment SYSCALL, which has been supported for quite some time. Signed-off-by: Jan Beulich --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -5975,6 +5975,60 @@ x86_emulate( goto done; break; + case X86EMUL_OPC(0x0f, 0x07): /* sysret */ + vcpu_must_have(syscall); + /* Inject #UD if syscall/sysret are disabled. */ + fail_if(!ops->read_msr); + if ( (rc = ops->read_msr(MSR_EFER, &msr_val, ctxt)) != X86EMUL_OKAY ) + goto done; + generate_exception_if((msr_val & EFER_SCE) == 0, EXC_UD); + generate_exception_if(!amd_like(ctxt) && !mode_64bit(), EXC_UD); + generate_exception_if(!mode_ring0(), EXC_GP, 0); + generate_exception_if(!in_protmode(ctxt, ops), EXC_GP, 0); + + if ( (rc = ops->read_msr(MSR_STAR, &msr_val, ctxt)) != X86EMUL_OKAY ) + goto done; + + sreg.sel = ((msr_val >> 48) + 8) | 3; /* SELECTOR_RPL_MASK */ + cs.sel = op_bytes == 8 ? sreg.sel + 8 : sreg.sel - 8; + + cs.base = sreg.base = 0; /* flat segment */ + cs.limit = sreg.limit = ~0u; /* 4GB limit */ + cs.attr = 0xcfb; /* G+DB+P+DPL3+S+Code */ + sreg.attr = 0xcf3; /* G+DB+P+DPL3+S+Data */ + +#ifdef __x86_64__ + if ( mode_64bit() ) + { + if ( op_bytes == 8 ) + { + cs.attr = 0xafb; /* L+DB+P+DPL3+S+Code */ + generate_exception_if(!is_canonical_address(_regs.rcx) && + !amd_like(ctxt), EXC_GP, 0); + _regs.rip = _regs.rcx; + } + else + _regs.rip = _regs.ecx; + + _regs.eflags = _regs.r11 & ~(X86_EFLAGS_RF | X86_EFLAGS_VM); + } + else +#endif + { + _regs.r(ip) = _regs.ecx; + _regs.eflags |= X86_EFLAGS_IF; + } + + fail_if(!ops->write_segment); + if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) != X86EMUL_OKAY || + (!amd_like(ctxt) && + (rc = ops->write_segment(x86_seg_ss, &sreg, + ctxt)) != X86EMUL_OKAY) ) + goto done; + + singlestep = _regs.eflags & X86_EFLAGS_TF; + break; + case X86EMUL_OPC(0x0f, 0x08): /* invd */ case X86EMUL_OPC(0x0f, 0x09): /* wbinvd / wbnoinvd */ generate_exception_if(!mode_ring0(), EXC_GP, 0);