From patchwork Fri Jan 25 15:41:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 10781611 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 99CFF1515 for ; Fri, 25 Jan 2019 15:42:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 893B22F750 for ; Fri, 25 Jan 2019 15:42:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7DC9F2F7C2; Fri, 25 Jan 2019 15:42:30 +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 D4BB72F750 for ; Fri, 25 Jan 2019 15:42:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728821AbfAYPm0 (ORCPT ); Fri, 25 Jan 2019 10:42:26 -0500 Received: from mga09.intel.com ([134.134.136.24]:54656 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728816AbfAYPlu (ORCPT ); Fri, 25 Jan 2019 10:41:50 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jan 2019 07:41:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,521,1539673200"; d="scan'208";a="128877880" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.14]) by orsmga002.jf.intel.com with ESMTP; 25 Jan 2019 07:41:46 -0800 From: Sean Christopherson To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: kvm@vger.kernel.org, Jim Mattson , Konrad Rzeszutek Wilk Subject: [PATCH v3 13/33] KVM: nVMX: Reference vmx->loaded_vmcs->launched directly Date: Fri, 25 Jan 2019 07:41:00 -0800 Message-Id: <20190125154120.19385-14-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190125154120.19385-1-sean.j.christopherson@intel.com> References: <20190125154120.19385-1-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 Temporarily propagating vmx->loaded_vmcs->launched to vmx->__launched is not functionally necessary, but rather was done historically to avoid passing both 'vmx' and 'loaded_vmcs' to the vCPU-run asm blob. Nested early checks inherited this behavior by virtue of copy+paste. A future patch will move HOST_RSP caching to be per-VMCS, i.e. store 'host_rsp' in loaded VMCS. Now that the reference to 'vmx->fail' is also gone from nested early checks, referencing 'loaded_vmcs' directly means we can drop the 'vmx' reference when introducing per-VMCS RSP caching. And it means __launched can be dropped from struct vcpu_vmx if/when vCPU-run receives similar treatment. Note the use of a named register constraint for 'loaded_vmcs'. Using RCX to hold 'vmx' was inherited from vCPU-run. In the vCPU-run case, the scratch register needs to be explicitly defined as it is crushed when loading guest state, i.e. deferring to the compiler would corrupt the pointer. Since nested early checks never loads guests state, it's a-ok to let the compiler pick any register. Naming the constraint avoids the fragility of referencing constraints via %1, %2, etc.., which breaks horribly when modifying constraints, and generally makes the asm blob more readable. Signed-off-by: Sean Christopherson Reviewed-by: Jim Mattson --- arch/x86/kvm/vmx/nested.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 15a8ae7bb247..d42134f836a6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2751,8 +2751,6 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) vmx->loaded_vmcs->host_state.cr4 = cr4; } - vmx->__launched = vmx->loaded_vmcs->launched; - asm( /* Set HOST_RSP */ "sub $%c[wordsize], %%" _ASM_SP "\n\t" /* temporarily adjust RSP for CALL */ @@ -2761,7 +2759,7 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) "add $%c[wordsize], %%" _ASM_SP "\n\t" /* un-adjust RSP */ /* Check if vmlaunch or vmresume is needed */ - "cmpb $0, %c[launched](%% " _ASM_CX")\n\t" + "cmpb $0, %c[launched](%[loaded_vmcs])\n\t" /* * VMLAUNCH and VMRESUME clear RFLAGS.{CF,ZF} on VM-Exit, set @@ -2774,7 +2772,8 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu) CC_SET(be) : ASM_CALL_CONSTRAINT, CC_OUT(be) (vm_fail) : "c"(vmx), "d"((unsigned long)HOST_RSP), - [launched]"i"(offsetof(struct vcpu_vmx, __launched)), + [loaded_vmcs]"r"(vmx->loaded_vmcs), + [launched]"i"(offsetof(struct loaded_vmcs, launched)), [host_rsp]"i"(offsetof(struct vcpu_vmx, host_rsp)), [wordsize]"i"(sizeof(ulong)) : "cc", "memory"