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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 11BBEC31E43 for ; Mon, 10 Jun 2019 16:30:52 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 95B5C20859 for ; Mon, 10 Jun 2019 16:30:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95B5C20859 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1F7F34A512; Mon, 10 Jun 2019 12:30:51 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Ig2IrPqC602z; Mon, 10 Jun 2019 12:30:49 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C97264A4DF; Mon, 10 Jun 2019 12:30:49 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 27A6C4A4DF for ; Mon, 10 Jun 2019 12:30:48 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IPezOi1Orhqi for ; Mon, 10 Jun 2019 12:30:46 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B3B9F4A4D5 for ; Mon, 10 Jun 2019 12:30:46 -0400 (EDT) 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 4FBB0337; Mon, 10 Jun 2019 09:30:46 -0700 (PDT) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3083C3F246; Mon, 10 Jun 2019 09:30:45 -0700 (PDT) From: James Morse To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v2] KVM: arm64: Skip more of the SError vaxorcism Date: Mon, 10 Jun 2019 17:30:34 +0100 Message-Id: <20190610163034.116151-1-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Cc: Marc Zyngier , Catalin Marinas , Will Deacon X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu 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. 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 --- This patch was previously posted as part of: [v1] https://lore.kernel.org/linux-arm-kernel/20190604144551.188107-1-james.morse@arm.com/ 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 a5a4254314a1..c2de1a1faaf4 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -161,18 +161,24 @@ alternative_if ARM64_HAS_RAS_EXTN orr x0, x0, #(1<