From nobody Mon Feb 9 15:09:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 331D4C3DA71 for ; Tue, 17 Jan 2023 22:02:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229894AbjAQWCc (ORCPT ); Tue, 17 Jan 2023 17:02:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229946AbjAQWAV (ORCPT ); Tue, 17 Jan 2023 17:00:21 -0500 Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [IPv6:2a00:1450:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F0E747EEC for ; Tue, 17 Jan 2023 12:44:32 -0800 (PST) Received: by mail-ej1-x634.google.com with SMTP id az20so59167748ejc.1 for ; Tue, 17 Jan 2023 12:44:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=grsecurity.net; s=grsec; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=b6W0pZJ6ERcXnvSOd8zNWpB3EIqXZWM69qX+jHbVTMc=; b=er4wt1Svi0Y85oW78y9sl9lSGk+Wf42JAlR88xK4S5USzWsvXKWg+Fkt2qwihepcm4 SSexx+TegUzDFg7KORa6CLfiI/nc/t5TpZJ+a/G06Gl9t8THrqbYa8kwruCUceUwki2p 8bA3INfGTW9/zzYJeMpNEnLNb2jPWEdV2QR3IaPeJVNe3qNQlHAeQ41fDTbw7NyS+Rjc 1AN+PmALVahnZzyIIN/m6bGQRMOjpCRShMsGJC3udNo9D/pZ90Kszp04UaWK9bpYu6Um zA5W4+7k5B/6kAyo9t2FqdqFAEaV34LpHZ2jxixoZLi97s779ggPk9ios9hvPMdUQ+Qd nBSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=b6W0pZJ6ERcXnvSOd8zNWpB3EIqXZWM69qX+jHbVTMc=; b=Y8SHCYKTxOP8AR52pIy3dtTjHcPEHLJL7jBWt1g+wZvLd1KK96JMDsBwkecgdYgEqY zbA3k2zb1eN781WP5et54x0oegxloId3XYJuAJQKafe6qD+V0uwu2LgJTWFNfudYldE4 tNi7XEX3yWQ28fPCOAXYGQGU+pbMQBcM2yry12v3EYo03zoyL9lFfkxZzE/Bb7iDlxE4 abDo0RHB2WmySv2kV9wmytoo7lC6wRch9t123gircqK2rkiPPCFBO2SXahh/jedsW1Ge kIophuKYL1qPLbRZcEVHkq5l3nmsS40vYy5zNvrlAt3VwdmUGimXrS+agVaXqqHf8rDy opsA== X-Gm-Message-State: AFqh2ko4tinfUOopS3dMyyPZKnB2wD63cJGIuXgh4nl+pXw9eYMbLLiS 7Jup+rY6qi/lL2XOPVxfVLUF2A== X-Google-Smtp-Source: AMrXdXs2Fbfj0IqNlTd1tPNrNN+Q5dOJWuBjOk2uTxTLcCawwkLNAeevJOP2YGOCo7VqLGzs5KaNzw== X-Received: by 2002:a17:907:8b08:b0:838:9b81:1c98 with SMTP id sz8-20020a1709078b0800b008389b811c98mr4478297ejc.1.1673988270861; Tue, 17 Jan 2023 12:44:30 -0800 (PST) Received: from nuc.fritz.box (p200300f6af098f00245ad18781b5e181.dip0.t-ipconnect.de. [2003:f6:af09:8f00:245a:d187:81b5:e181]) by smtp.gmail.com with ESMTPSA id k2-20020a170906970200b0073dbaeb50f6sm13477051ejx.169.2023.01.17.12.44.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jan 2023 12:44:30 -0800 (PST) From: Mathias Krause To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , Paolo Bonzini , Mathias Krause Subject: [PATCH 2/3] KVM: VMX: avoid retpoline call for control register caused exits Date: Tue, 17 Jan 2023 21:45:55 +0100 Message-Id: <20230117204556.16217-3-minipli@grsecurity.net> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230117204556.16217-1-minipli@grsecurity.net> References: <20230117204556.16217-1-minipli@grsecurity.net> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Complement commit 4289d2728664 ("KVM: retpolines: x86: eliminate retpoline from vmx.c exit handlers") and avoid a retpoline call for control register accesses as well. This speeds up guests that make heavy use of it, like grsecurity kernels toggling CR0.WP to implement kernel W^X. Signed-off-by: Mathias Krause --- SVM may gain from a similar change as well, however, I've no AMD box to test this on. arch/x86/kvm/vmx/vmx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index c788aa382611..c8198c8a9b55 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6538,6 +6538,8 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, f= astpath_t exit_fastpath) return handle_external_interrupt(vcpu); else if (exit_reason.basic =3D=3D EXIT_REASON_HLT) return kvm_emulate_halt(vcpu); + else if (exit_reason.basic =3D=3D EXIT_REASON_CR_ACCESS) + return handle_cr(vcpu); else if (exit_reason.basic =3D=3D EXIT_REASON_EPT_MISCONFIG) return handle_ept_misconfig(vcpu); #endif --=20 2.39.0