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=-9.8 required=3.0 tests=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 426D3C73C42 for ; Tue, 9 Jul 2019 12:25:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24D84214AF for ; Tue, 9 Jul 2019 12:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726762AbfGIMZh (ORCPT ); Tue, 9 Jul 2019 08:25:37 -0400 Received: from foss.arm.com ([217.140.110.172]:42738 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726592AbfGIMZh (ORCPT ); Tue, 9 Jul 2019 08:25:37 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3516E152F; Tue, 9 Jul 2019 05:25:36 -0700 (PDT) Received: from filthy-habits.cambridge.arm.com (unknown [10.1.197.61]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 673BA3F59C; Tue, 9 Jul 2019 05:25:34 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: Andre Przywara , Andrew Murray , Dave Martin , Eric Auger , James Morse , Julien Thierry , Steven Price , Sudeep Holla , Suzuki K Poulose , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 08/18] KVM: arm64: Skip more of the SError vaxorcism Date: Tue, 9 Jul 2019 13:24:57 +0100 Message-Id: <20190709122507.214494-9-marc.zyngier@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190709122507.214494-1-marc.zyngier@arm.com> References: <20190709122507.214494-1-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: James Morse During __guest_exit() we need to consume any SError left pending by the guest so it doesn't contaminate the host. With v8.2 we use the ESB-instruction. For systems without v8.2, we use dsb+isb and unmask SError. We do this on every guest exit. Use the same dsb+isr_el1 trick, this lets us know if an SError is pending after the dsb, allowing us to skip the isb and self-synchronising PSTATE write if its not. This means SError remains masked during KVM's world-switch, so any SError that occurs during this time is reported by the host, instead of causing a hyp-panic. As we're benchmarking this code lets polish the layout. If you give gcc likely()/unlikely() hints in an if() condition, it shuffles the generated assembly so that the likely case is immediately after the branch. Lets do the same here. Signed-off-by: James Morse Changes since v2: * Added isb after the dsb to prevent an early read Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/entry.S | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 5e25cc0e6aab..e5cc8d66bf53 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -151,8 +151,16 @@ alternative_if ARM64_HAS_RAS_EXTN orr x0, x0, #(1<