From patchwork Thu Dec 20 20:25:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 10739555 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 064A814E5 for ; Thu, 20 Dec 2018 20:25:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB1BE28D05 for ; Thu, 20 Dec 2018 20:25:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DF29D28D11; Thu, 20 Dec 2018 20:25:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8598928D05 for ; Thu, 20 Dec 2018 20:25:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732875AbeLTUZm (ORCPT ); Thu, 20 Dec 2018 15:25:42 -0500 Received: from mga14.intel.com ([192.55.52.115]:65141 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732346AbeLTUZl (ORCPT ); Thu, 20 Dec 2018 15:25:41 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Dec 2018 12:25:39 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,378,1539673200"; d="scan'208";a="112203703" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.154]) by orsmga003.jf.intel.com with ESMTP; 20 Dec 2018 12:25:39 -0800 From: Sean Christopherson To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Miguel Ojeda Cc: kvm@vger.kernel.org, Andi Kleen , Martin Jambor , Nadav Amit , Josh Poimboeuf , Arnd Bergmann , Steven Rostedt , Miroslav Benes Subject: [PATCH 01/11] KVM: VMX: Explicitly reference RCX as the vmx_vcpu pointer in asm blobs Date: Thu, 20 Dec 2018 12:25:16 -0800 Message-Id: <20181220202518.21442-2-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181220202518.21442-1-sean.j.christopherson@intel.com> References: <20181220202518.21442-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Use '%% " _ASM_CX"' instead of '%0' to dereference RCX, i.e. the 'struct vmx_vcpu' pointer, in the VM-Enter asm blobs of vmx_vcpu_run() and nested_vmx_check_vmentry_hw(). Using the symbolic name means that adding/removing an output parameter(s) requires "rewriting" almost all of the asm blob, which makes it nearly impossible to understand what's being changed in even the most minor patches. Opportunistically improve the code comments. Signed-off-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/nested.c | 6 +-- arch/x86/kvm/vmx/vmx.c | 86 +++++++++++++++++++++------------------ 2 files changed, 50 insertions(+), 42 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 3f019aa63341..43b33cd23ac5 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2759,17 +2759,17 @@ static int __noclone nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) asm( /* Set HOST_RSP */ __ex("vmwrite %%" _ASM_SP ", %%" _ASM_DX) "\n\t" - "mov %%" _ASM_SP ", %c[host_rsp](%0)\n\t" + "mov %%" _ASM_SP ", %c[host_rsp](%% " _ASM_CX")\n\t" /* Check if vmlaunch or vmresume is needed */ - "cmpl $0, %c[launched](%0)\n\t" + "cmpl $0, %c[launched](%% " _ASM_CX")\n\t" "jne 1f\n\t" __ex("vmlaunch") "\n\t" "jmp 2f\n\t" "1: " __ex("vmresume") "\n\t" "2: " /* Set vmx->fail accordingly */ - "setbe %c[fail](%0)\n\t" + "setbe %c[fail](%% " _ASM_CX")\n\t" ".pushsection .rodata\n\t" ".global vmx_early_consistency_check_return\n\t" diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index b8fa74ce3af2..42bfcd28c27b 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6124,9 +6124,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) "push %%" _ASM_DX "; push %%" _ASM_BP ";" "push %%" _ASM_CX " \n\t" /* placeholder for guest rcx */ "push %%" _ASM_CX " \n\t" - "cmp %%" _ASM_SP ", %c[host_rsp](%0) \n\t" + "cmp %%" _ASM_SP ", %c[host_rsp](%%" _ASM_CX ") \n\t" "je 1f \n\t" - "mov %%" _ASM_SP ", %c[host_rsp](%0) \n\t" + "mov %%" _ASM_SP ", %c[host_rsp](%%" _ASM_CX ") \n\t" /* Avoid VMWRITE when Enlightened VMCS is in use */ "test %%" _ASM_SI ", %%" _ASM_SI " \n\t" "jz 2f \n\t" @@ -6136,32 +6136,33 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) __ex("vmwrite %%" _ASM_SP ", %%" _ASM_DX) "\n\t" "1: \n\t" /* Reload cr2 if changed */ - "mov %c[cr2](%0), %%" _ASM_AX " \n\t" + "mov %c[cr2](%%" _ASM_CX "), %%" _ASM_AX " \n\t" "mov %%cr2, %%" _ASM_DX " \n\t" "cmp %%" _ASM_AX ", %%" _ASM_DX " \n\t" "je 3f \n\t" "mov %%" _ASM_AX", %%cr2 \n\t" "3: \n\t" /* Check if vmlaunch or vmresume is needed */ - "cmpl $0, %c[launched](%0) \n\t" + "cmpl $0, %c[launched](%%" _ASM_CX ") \n\t" /* Load guest registers. Don't clobber flags. */ - "mov %c[rax](%0), %%" _ASM_AX " \n\t" - "mov %c[rbx](%0), %%" _ASM_BX " \n\t" - "mov %c[rdx](%0), %%" _ASM_DX " \n\t" - "mov %c[rsi](%0), %%" _ASM_SI " \n\t" - "mov %c[rdi](%0), %%" _ASM_DI " \n\t" - "mov %c[rbp](%0), %%" _ASM_BP " \n\t" + "mov %c[rax](%%" _ASM_CX "), %%" _ASM_AX " \n\t" + "mov %c[rbx](%%" _ASM_CX "), %%" _ASM_BX " \n\t" + "mov %c[rdx](%%" _ASM_CX "), %%" _ASM_DX " \n\t" + "mov %c[rsi](%%" _ASM_CX "), %%" _ASM_SI " \n\t" + "mov %c[rdi](%%" _ASM_CX "), %%" _ASM_DI " \n\t" + "mov %c[rbp](%%" _ASM_CX "), %%" _ASM_BP " \n\t" #ifdef CONFIG_X86_64 - "mov %c[r8](%0), %%r8 \n\t" - "mov %c[r9](%0), %%r9 \n\t" - "mov %c[r10](%0), %%r10 \n\t" - "mov %c[r11](%0), %%r11 \n\t" - "mov %c[r12](%0), %%r12 \n\t" - "mov %c[r13](%0), %%r13 \n\t" - "mov %c[r14](%0), %%r14 \n\t" - "mov %c[r15](%0), %%r15 \n\t" + "mov %c[r8](%%" _ASM_CX "), %%r8 \n\t" + "mov %c[r9](%%" _ASM_CX "), %%r9 \n\t" + "mov %c[r10](%%" _ASM_CX "), %%r10 \n\t" + "mov %c[r11](%%" _ASM_CX "), %%r11 \n\t" + "mov %c[r12](%%" _ASM_CX "), %%r12 \n\t" + "mov %c[r13](%%" _ASM_CX "), %%r13 \n\t" + "mov %c[r14](%%" _ASM_CX "), %%r14 \n\t" + "mov %c[r15](%%" _ASM_CX "), %%r15 \n\t" #endif - "mov %c[rcx](%0), %%" _ASM_CX " \n\t" /* kills %0 (ecx) */ + /* Load guest RCX. This kills the vmx_vcpu pointer! */ + "mov %c[rcx](%%" _ASM_CX "), %%" _ASM_CX " \n\t" /* Enter guest mode */ "jne 1f \n\t" @@ -6169,26 +6170,33 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) "jmp 2f \n\t" "1: " __ex("vmresume") "\n\t" "2: " - /* Save guest registers, load host registers, keep flags */ - "mov %0, %c[wordsize](%%" _ASM_SP ") \n\t" - "pop %0 \n\t" - "setbe %c[fail](%0)\n\t" - "mov %%" _ASM_AX ", %c[rax](%0) \n\t" - "mov %%" _ASM_BX ", %c[rbx](%0) \n\t" - __ASM_SIZE(pop) " %c[rcx](%0) \n\t" - "mov %%" _ASM_DX ", %c[rdx](%0) \n\t" - "mov %%" _ASM_SI ", %c[rsi](%0) \n\t" - "mov %%" _ASM_DI ", %c[rdi](%0) \n\t" - "mov %%" _ASM_BP ", %c[rbp](%0) \n\t" + + /* Save guest's RCX to the stack placeholder (see above) */ + "mov %%" _ASM_CX ", %c[wordsize](%%" _ASM_SP ") \n\t" + + /* Load host's RCX, i.e. the vmx_vcpu pointer */ + "pop %%" _ASM_CX " \n\t" + + /* Set vmx->fail based on EFLAGS.{CF,ZF} */ + "setbe %c[fail](%%" _ASM_CX ")\n\t" + + /* Save all guest registers, including RCX from the stack */ + "mov %%" _ASM_AX ", %c[rax](%%" _ASM_CX ") \n\t" + "mov %%" _ASM_BX ", %c[rbx](%%" _ASM_CX ") \n\t" + __ASM_SIZE(pop) " %c[rcx](%%" _ASM_CX ") \n\t" + "mov %%" _ASM_DX ", %c[rdx](%%" _ASM_CX ") \n\t" + "mov %%" _ASM_SI ", %c[rsi](%%" _ASM_CX ") \n\t" + "mov %%" _ASM_DI ", %c[rdi](%%" _ASM_CX ") \n\t" + "mov %%" _ASM_BP ", %c[rbp](%%" _ASM_CX ") \n\t" #ifdef CONFIG_X86_64 - "mov %%r8, %c[r8](%0) \n\t" - "mov %%r9, %c[r9](%0) \n\t" - "mov %%r10, %c[r10](%0) \n\t" - "mov %%r11, %c[r11](%0) \n\t" - "mov %%r12, %c[r12](%0) \n\t" - "mov %%r13, %c[r13](%0) \n\t" - "mov %%r14, %c[r14](%0) \n\t" - "mov %%r15, %c[r15](%0) \n\t" + "mov %%r8, %c[r8](%%" _ASM_CX ") \n\t" + "mov %%r9, %c[r9](%%" _ASM_CX ") \n\t" + "mov %%r10, %c[r10](%%" _ASM_CX ") \n\t" + "mov %%r11, %c[r11](%%" _ASM_CX ") \n\t" + "mov %%r12, %c[r12](%%" _ASM_CX ") \n\t" + "mov %%r13, %c[r13](%%" _ASM_CX ") \n\t" + "mov %%r14, %c[r14](%%" _ASM_CX ") \n\t" + "mov %%r15, %c[r15](%%" _ASM_CX ") \n\t" /* * Clear host registers marked as clobbered to prevent * speculative use. @@ -6203,7 +6211,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) "xor %%r15d, %%r15d \n\t" #endif "mov %%cr2, %%" _ASM_AX " \n\t" - "mov %%" _ASM_AX ", %c[cr2](%0) \n\t" + "mov %%" _ASM_AX ", %c[cr2](%%" _ASM_CX ") \n\t" "xor %%eax, %%eax \n\t" "xor %%ebx, %%ebx \n\t"