From patchwork Mon Nov 16 18:26:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 11910409 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3302C64E7A for ; Mon, 16 Nov 2020 18:32:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A253A206E0 for ; Mon, 16 Nov 2020 18:32:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388621AbgKPSbr (ORCPT ); Mon, 16 Nov 2020 13:31:47 -0500 Received: from mga06.intel.com ([134.134.136.31]:20636 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388104AbgKPS2H (ORCPT ); Mon, 16 Nov 2020 13:28:07 -0500 IronPort-SDR: LyT4YNPKVF3BeXDaQa1ur2noX03aG+tv/L+Ztl3hWzZriUvbcQ6vMhQZne43mxFACzDKxdjZOW LFbldh9G5SLA== X-IronPort-AV: E=McAfee;i="6000,8403,9807"; a="232410039" X-IronPort-AV: E=Sophos;i="5.77,483,1596524400"; d="scan'208";a="232410039" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Nov 2020 10:28:06 -0800 IronPort-SDR: ASwCFKCLy4OB4+gf56DduJlNArpGMnds+U8gtJMjxBGFNEsyjNPUrk1yfQiQe2DK7ACyGhmNp8 k1mX1KP5X9Iw== X-IronPort-AV: E=Sophos;i="5.77,483,1596524400"; d="scan'208";a="400528033" Received: from ls.sc.intel.com (HELO localhost) ([143.183.96.54]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Nov 2020 10:28:05 -0800 From: isaku.yamahata@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Sean Christopherson Subject: [RFC PATCH 29/67] KVM: x86: Add a switch_db_regs flag to handle TDX's auto-switched behavior Date: Mon, 16 Nov 2020 10:26:14 -0800 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Sean Christopherson Add a flag, KVM_DEBUGREG_AUTO_SWITCHED, to skip saving/restoring DRs irrespective of any other flags. TDX-SEAM unconditionally saves and restores host DRs, ergo there is nothing to do. Opportunistically convert the KVM_DEBUGREG_* definitions to use BIT(). Reported-by: Xiaoyao Li Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 7 ++++--- arch/x86/kvm/x86.c | 6 ++++-- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index a6c89666ec49..815469875445 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -464,9 +464,10 @@ struct kvm_pmu { struct kvm_pmu_ops; enum { - KVM_DEBUGREG_BP_ENABLED = 1, - KVM_DEBUGREG_WONT_EXIT = 2, - KVM_DEBUGREG_RELOAD = 4, + KVM_DEBUGREG_BP_ENABLED = BIT(0), + KVM_DEBUGREG_WONT_EXIT = BIT(1), + KVM_DEBUGREG_RELOAD = BIT(2), + KVM_DEBUGREG_AUTO_SWITCHED = BIT(3), }; struct kvm_mtrr_range { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 42bd24ba7fdd..098888edc3ad 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9009,7 +9009,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (test_thread_flag(TIF_NEED_FPU_LOAD)) switch_fpu_return(); - if (unlikely(vcpu->arch.switch_db_regs)) { + if (unlikely(vcpu->arch.switch_db_regs & ~KVM_DEBUGREG_AUTO_SWITCHED)) { set_debugreg(0, 7); set_debugreg(vcpu->arch.eff_db[0], 0); set_debugreg(vcpu->arch.eff_db[1], 1); @@ -9029,6 +9029,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) */ if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) { WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP); + WARN_ON(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCHED); kvm_x86_ops.sync_dirty_debug_regs(vcpu); kvm_update_dr0123(vcpu); kvm_update_dr7(vcpu); @@ -9042,7 +9043,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) * care about the messed up debug address registers. But if * we have some of them active, restore the old state. */ - if (hw_breakpoint_active()) + if (hw_breakpoint_active() && + !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCHED)) hw_breakpoint_restore(); vcpu->arch.last_vmentry_cpu = vcpu->cpu;