From patchwork Mon Sep 3 13:45:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoffer Dall X-Patchwork-Id: 10585973 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 C2FEF16B1 for ; Mon, 3 Sep 2018 13:48:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AEDE229709 for ; Mon, 3 Sep 2018 13:48:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A2F1A297C5; Mon, 3 Sep 2018 13:48:58 +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=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2D09E29709 for ; Mon, 3 Sep 2018 13:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ubPclmROEZlL5iecsojNAY3IyHfXwerRFxMO9x8QVis=; b=ML9Rl53UgGCfIA2BfsF51lsbtp jvv19yB9B+XSgjTj5OIFRwFmgrC+jJkeKwjRv8BxFy+7bysNHrFv24bu3omc7VwPASxb5dRBcbqHk 3G/rh2WPWqPF+bvf2Qii58lSTMVqGwr0YcnBrMiM4sKFbgbh8+ZvUGyaPFnuTwa1LbAMV2WjH7VOp nSD3DpQ27nf1IUJPGelLzfUq/kFDx/0ROhKkL731OSVX/Sz3ZuCNDTVExJH9fXSHdq9tjT7QJCfQM KqaSURluJQsOGTH9Flboar/jyyNXdItbBtR7dSFnKNSWlOEvNFLeCQl9JJYwbL/CiYe3BToDpLQTF 7KqVMq7w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fwpDl-0003jL-Cr; Mon, 03 Sep 2018 13:48:49 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fwpAZ-0001z7-Lh for linux-arm-kernel@lists.infradead.org; Mon, 03 Sep 2018 13:45:36 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 177D115B2; Mon, 3 Sep 2018 06:45:26 -0700 (PDT) Received: from localhost (e113682-lin.copenhagen.arm.com [10.32.144.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9EE9A3F557; Mon, 3 Sep 2018 06:45:25 -0700 (PDT) From: Christoffer Dall To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Subject: [PULL 2/4] arm64: KVM: Only force FPEXC32_EL2.EN if trapping FPSIMD Date: Mon, 3 Sep 2018 15:45:14 +0200 Message-Id: <20180903134516.17796-3-christoffer.dall@arm.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180903134516.17796-1-christoffer.dall@arm.com> References: <20180903134516.17796-1-christoffer.dall@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180903_064531_915987_7489C635 X-CRM114-Status: GOOD ( 12.74 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, Christoffer Dall , Marc Zyngier , Alexander Graf , kvmarm@lists.cs.columbia.edu, Dave Martin , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Marc Zyngier If trapping FPSIMD in the context of an AArch32 guest, it is critical to set FPEXC32_EL2.EN to 1 so that the trapping is taken to EL2 and not EL1. Conversely, it is just as critical *not* to set FPEXC32_EL2.EN to 1 if we're not going to trap FPSIMD, as we then corrupt the existing VFP state. Moving the call to __activate_traps_fpsimd32 to the point where we know for sure that we are going to trap ensures that we don't set that bit spuriously. Fixes: e6b673b741ea ("KVM: arm64: Optimise FPSIMD handling to reduce guest/host thrashing") Cc: Dave Martin Reported-by: Alexander Graf Tested-by: Alexander Graf Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm64/kvm/hyp/switch.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index d496ef579859..ca46153d7915 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -98,8 +98,10 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu) val = read_sysreg(cpacr_el1); val |= CPACR_EL1_TTA; val &= ~CPACR_EL1_ZEN; - if (!update_fp_enabled(vcpu)) + if (!update_fp_enabled(vcpu)) { val &= ~CPACR_EL1_FPEN; + __activate_traps_fpsimd32(vcpu); + } write_sysreg(val, cpacr_el1); @@ -114,8 +116,10 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) val = CPTR_EL2_DEFAULT; val |= CPTR_EL2_TTA | CPTR_EL2_TZ; - if (!update_fp_enabled(vcpu)) + if (!update_fp_enabled(vcpu)) { val |= CPTR_EL2_TFP; + __activate_traps_fpsimd32(vcpu); + } write_sysreg(val, cptr_el2); } @@ -129,7 +133,6 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE)) write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); - __activate_traps_fpsimd32(vcpu); if (has_vhe()) activate_traps_vhe(vcpu); else