From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id C22F4C07D5C for ; Thu, 14 Jun 2018 08:25:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E37C208D7 for ; Thu, 14 Jun 2018 08:25:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E37C208D7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754902AbeFNIZh (ORCPT ); Thu, 14 Jun 2018 04:25:37 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54709 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752867AbeFNIZ3 (ORCPT ); Thu, 14 Jun 2018 04:25:29 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DAF684074458; Thu, 14 Jun 2018 08:25:28 +0000 (UTC) Received: from vitty.brq.redhat.com (ovpn-204-228.brq.redhat.com [10.40.204.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6B1BB10FFE4D; Thu, 14 Jun 2018 08:25:25 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Roman Kagan , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , Mohammed Gamal , Cathy Avery , linux-kernel@vger.kernel.org, Jim Mattson Subject: [PATCH 5/5] KVM: nVMX: optimize prepare_vmcs02{,_full} for Enlightened VMCS case Date: Thu, 14 Jun 2018 10:25:00 +0200 Message-Id: <20180614082500.18548-6-vkuznets@redhat.com> In-Reply-To: <20180614082500.18548-1-vkuznets@redhat.com> References: <20180614082500.18548-1-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Thu, 14 Jun 2018 08:25:28 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Thu, 14 Jun 2018 08:25:28 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'vkuznets@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When Enlightened VMCS is in use by L1 hypervisor we can avoid vmwriting VMCS fields which did not change. Our first goal is to achieve minimal impact on traditional VMCS case so we're not wrapping each vmwrite() with an if-changed checker. We also can't utilize static keys as Enlightened VMCS usage is per-guest. This patch implements the simpliest solution: checking fields in groups. We skip single vmwrite() statements as doing the check will cost us something even in non-evmcs case and the win is tiny. Unfortunately, this makes prepare_vmcs02_full{,_full}() code Enlightened VMCS-dependent (and a bit ugly). Signed-off-by: Vitaly Kuznetsov --- arch/x86/kvm/vmx.c | 143 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 82 insertions(+), 61 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 6802ba91468c..9a7d76c5c92b 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11619,50 +11619,79 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne return 0; } +/* + * Check if L1 hypervisor changed the particular field in Enlightened + * VMCS and avoid redundant vmwrite if it didn't. Can only be used when + * the value we're about to write is unchanged vmcs12->field. + */ +#define evmcs_needs_write(vmx, clean_field) ((vmx)->nested.dirty_vmcs12 ||\ + !(vmx->nested.hv_evmcs->hv_clean_fields &\ + HV_VMX_ENLIGHTENED_CLEAN_FIELD_##clean_field)) + static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) { struct vcpu_vmx *vmx = to_vmx(vcpu); + struct hv_enlightened_vmcs *hv_evmcs = vmx->nested.hv_evmcs; + + if (!hv_evmcs || evmcs_needs_write(vmx, GUEST_GRP2)) { + vmcs_write16(GUEST_ES_SELECTOR, vmcs12->guest_es_selector); + vmcs_write16(GUEST_SS_SELECTOR, vmcs12->guest_ss_selector); + vmcs_write16(GUEST_DS_SELECTOR, vmcs12->guest_ds_selector); + vmcs_write16(GUEST_FS_SELECTOR, vmcs12->guest_fs_selector); + vmcs_write16(GUEST_GS_SELECTOR, vmcs12->guest_gs_selector); + vmcs_write16(GUEST_LDTR_SELECTOR, vmcs12->guest_ldtr_selector); + vmcs_write16(GUEST_TR_SELECTOR, vmcs12->guest_tr_selector); + vmcs_write32(GUEST_ES_LIMIT, vmcs12->guest_es_limit); + vmcs_write32(GUEST_SS_LIMIT, vmcs12->guest_ss_limit); + vmcs_write32(GUEST_DS_LIMIT, vmcs12->guest_ds_limit); + vmcs_write32(GUEST_FS_LIMIT, vmcs12->guest_fs_limit); + vmcs_write32(GUEST_GS_LIMIT, vmcs12->guest_gs_limit); + vmcs_write32(GUEST_LDTR_LIMIT, vmcs12->guest_ldtr_limit); + vmcs_write32(GUEST_TR_LIMIT, vmcs12->guest_tr_limit); + vmcs_write32(GUEST_GDTR_LIMIT, vmcs12->guest_gdtr_limit); + vmcs_write32(GUEST_IDTR_LIMIT, vmcs12->guest_idtr_limit); + vmcs_write32(GUEST_ES_AR_BYTES, vmcs12->guest_es_ar_bytes); + vmcs_write32(GUEST_SS_AR_BYTES, vmcs12->guest_ss_ar_bytes); + vmcs_write32(GUEST_DS_AR_BYTES, vmcs12->guest_ds_ar_bytes); + vmcs_write32(GUEST_FS_AR_BYTES, vmcs12->guest_fs_ar_bytes); + vmcs_write32(GUEST_GS_AR_BYTES, vmcs12->guest_gs_ar_bytes); + vmcs_write32(GUEST_LDTR_AR_BYTES, vmcs12->guest_ldtr_ar_bytes); + vmcs_write32(GUEST_TR_AR_BYTES, vmcs12->guest_tr_ar_bytes); + vmcs_writel(GUEST_SS_BASE, vmcs12->guest_ss_base); + vmcs_writel(GUEST_DS_BASE, vmcs12->guest_ds_base); + vmcs_writel(GUEST_FS_BASE, vmcs12->guest_fs_base); + vmcs_writel(GUEST_GS_BASE, vmcs12->guest_gs_base); + vmcs_writel(GUEST_LDTR_BASE, vmcs12->guest_ldtr_base); + vmcs_writel(GUEST_TR_BASE, vmcs12->guest_tr_base); + vmcs_writel(GUEST_GDTR_BASE, vmcs12->guest_gdtr_base); + vmcs_writel(GUEST_IDTR_BASE, vmcs12->guest_idtr_base); + } + + if (!hv_evmcs || evmcs_needs_write(vmx, GUEST_GRP1)) { + vmcs_write32(GUEST_SYSENTER_CS, vmcs12->guest_sysenter_cs); + vmcs_writel(GUEST_PENDING_DBG_EXCEPTIONS, + vmcs12->guest_pending_dbg_exceptions); + vmcs_writel(GUEST_SYSENTER_ESP, vmcs12->guest_sysenter_esp); + vmcs_writel(GUEST_SYSENTER_EIP, vmcs12->guest_sysenter_eip); + + if (vmx_mpx_supported()) + vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs); - vmcs_write16(GUEST_ES_SELECTOR, vmcs12->guest_es_selector); - vmcs_write16(GUEST_SS_SELECTOR, vmcs12->guest_ss_selector); - vmcs_write16(GUEST_DS_SELECTOR, vmcs12->guest_ds_selector); - vmcs_write16(GUEST_FS_SELECTOR, vmcs12->guest_fs_selector); - vmcs_write16(GUEST_GS_SELECTOR, vmcs12->guest_gs_selector); - vmcs_write16(GUEST_LDTR_SELECTOR, vmcs12->guest_ldtr_selector); - vmcs_write16(GUEST_TR_SELECTOR, vmcs12->guest_tr_selector); - vmcs_write32(GUEST_ES_LIMIT, vmcs12->guest_es_limit); - vmcs_write32(GUEST_SS_LIMIT, vmcs12->guest_ss_limit); - vmcs_write32(GUEST_DS_LIMIT, vmcs12->guest_ds_limit); - vmcs_write32(GUEST_FS_LIMIT, vmcs12->guest_fs_limit); - vmcs_write32(GUEST_GS_LIMIT, vmcs12->guest_gs_limit); - vmcs_write32(GUEST_LDTR_LIMIT, vmcs12->guest_ldtr_limit); - vmcs_write32(GUEST_TR_LIMIT, vmcs12->guest_tr_limit); - vmcs_write32(GUEST_GDTR_LIMIT, vmcs12->guest_gdtr_limit); - vmcs_write32(GUEST_IDTR_LIMIT, vmcs12->guest_idtr_limit); - vmcs_write32(GUEST_ES_AR_BYTES, vmcs12->guest_es_ar_bytes); - vmcs_write32(GUEST_SS_AR_BYTES, vmcs12->guest_ss_ar_bytes); - vmcs_write32(GUEST_DS_AR_BYTES, vmcs12->guest_ds_ar_bytes); - vmcs_write32(GUEST_FS_AR_BYTES, vmcs12->guest_fs_ar_bytes); - vmcs_write32(GUEST_GS_AR_BYTES, vmcs12->guest_gs_ar_bytes); - vmcs_write32(GUEST_LDTR_AR_BYTES, vmcs12->guest_ldtr_ar_bytes); - vmcs_write32(GUEST_TR_AR_BYTES, vmcs12->guest_tr_ar_bytes); - vmcs_writel(GUEST_SS_BASE, vmcs12->guest_ss_base); - vmcs_writel(GUEST_DS_BASE, vmcs12->guest_ds_base); - vmcs_writel(GUEST_FS_BASE, vmcs12->guest_fs_base); - vmcs_writel(GUEST_GS_BASE, vmcs12->guest_gs_base); - vmcs_writel(GUEST_LDTR_BASE, vmcs12->guest_ldtr_base); - vmcs_writel(GUEST_TR_BASE, vmcs12->guest_tr_base); - vmcs_writel(GUEST_GDTR_BASE, vmcs12->guest_gdtr_base); - vmcs_writel(GUEST_IDTR_BASE, vmcs12->guest_idtr_base); - - vmcs_write32(GUEST_SYSENTER_CS, vmcs12->guest_sysenter_cs); - vmcs_writel(GUEST_PENDING_DBG_EXCEPTIONS, - vmcs12->guest_pending_dbg_exceptions); - vmcs_writel(GUEST_SYSENTER_ESP, vmcs12->guest_sysenter_esp); - vmcs_writel(GUEST_SYSENTER_EIP, vmcs12->guest_sysenter_eip); + /* + * L1 may access the L2's PDPTR, so save them to construct + * vmcs12 + */ + if (enable_ept) { + vmcs_write64(GUEST_PDPTR0, vmcs12->guest_pdptr0); + vmcs_write64(GUEST_PDPTR1, vmcs12->guest_pdptr1); + vmcs_write64(GUEST_PDPTR2, vmcs12->guest_pdptr2); + vmcs_write64(GUEST_PDPTR3, vmcs12->guest_pdptr3); + } + } if (nested_cpu_has_xsaves(vmcs12)) vmcs_write64(XSS_EXIT_BITMAP, vmcs12->xss_exit_bitmap); + vmcs_write64(VMCS_LINK_POINTER, -1ull); if (cpu_has_vmx_posted_intr()) @@ -11717,9 +11746,6 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) set_cr4_guest_host_mask(vmx); - if (vmx_mpx_supported()) - vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs); - if (enable_vpid) { if (nested_cpu_has_vpid(vmcs12) && vmx->nested.vpid02) vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->nested.vpid02); @@ -11727,16 +11753,6 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid); } - /* - * L1 may access the L2's PDPTR, so save them to construct vmcs12 - */ - if (enable_ept) { - vmcs_write64(GUEST_PDPTR0, vmcs12->guest_pdptr0); - vmcs_write64(GUEST_PDPTR1, vmcs12->guest_pdptr1); - vmcs_write64(GUEST_PDPTR2, vmcs12->guest_pdptr2); - vmcs_write64(GUEST_PDPTR3, vmcs12->guest_pdptr3); - } - if (cpu_has_vmx_msr_bitmap()) vmcs_write64(MSR_BITMAP, __pa(vmx->nested.vmcs02.msr_bitmap)); } @@ -11757,6 +11773,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, { struct vcpu_vmx *vmx = to_vmx(vcpu); u32 exec_control, vmcs12_exec_ctrl; + struct hv_enlightened_vmcs *hv_evmcs = vmx->nested.hv_evmcs; if (vmx->nested.dirty_vmcs12 || vmx->nested.hv_evmcs) { prepare_vmcs02_full(vcpu, vmcs12); @@ -11768,11 +11785,13 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, * with vmx_shadow_fields.h. */ - vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector); - vmcs_write32(GUEST_CS_LIMIT, vmcs12->guest_cs_limit); - vmcs_write32(GUEST_CS_AR_BYTES, vmcs12->guest_cs_ar_bytes); - vmcs_writel(GUEST_ES_BASE, vmcs12->guest_es_base); - vmcs_writel(GUEST_CS_BASE, vmcs12->guest_cs_base); + if (!hv_evmcs || evmcs_needs_write(vmx, GUEST_GRP2)) { + vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector); + vmcs_write32(GUEST_CS_LIMIT, vmcs12->guest_cs_limit); + vmcs_write32(GUEST_CS_AR_BYTES, vmcs12->guest_cs_ar_bytes); + vmcs_writel(GUEST_ES_BASE, vmcs12->guest_es_base); + vmcs_writel(GUEST_CS_BASE, vmcs12->guest_cs_base); + } /* * Not in vmcs02: GUEST_PML_INDEX, HOST_FS_SELECTOR, HOST_GS_SELECTOR, @@ -11788,12 +11807,14 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl); } if (vmx->nested.nested_run_pending) { - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, - vmcs12->vm_entry_intr_info_field); - vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, - vmcs12->vm_entry_exception_error_code); - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, - vmcs12->vm_entry_instruction_len); + if (!hv_evmcs || evmcs_needs_write(vmx, CONTROL_EVENT)) { + vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, + vmcs12->vm_entry_intr_info_field); + vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, + vmcs12->vm_entry_exception_error_code); + vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, + vmcs12->vm_entry_instruction_len); + } vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, vmcs12->guest_interruptibility_info); vmx->loaded_vmcs->nmi_known_unmasked = -- 2.14.4