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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=no 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 993A5C433E3 for ; Thu, 4 Jun 2020 13:34:10 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 1F83620772 for ; Thu, 4 Jun 2020 13:34:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PNA+5znU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F83620772 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 A574D4B32F; Thu, 4 Jun 2020 09:34:09 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org 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 QK7c+mThwyPD; Thu, 4 Jun 2020 09:34:08 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1A2684B346; Thu, 4 Jun 2020 09:34:08 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2A9574B2FE for ; Thu, 4 Jun 2020 09:34:07 -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 yerUg2YVPu1X for ; Thu, 4 Jun 2020 09:34:06 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 290C24B325 for ; Thu, 4 Jun 2020 09:34:06 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 099E120772; Thu, 4 Jun 2020 13:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591277645; bh=rcP0ID3sZv+j+DKkPTrcUriG90Uun00qknLwobPg9EU=; h=From:To:Cc:Subject:Date:From; b=PNA+5znUqtVizpteIx5iiQH+oJlxiDqad2kOGfq9Qemb6XNvFMSy8+8BhCaCxVeYF DuC1RWChGU82A86yA3iGVXIOGL7Ke90uWaxbkMVFnsbCI86sf594bpQ2s6Wy1we3xu 1LTE4mL0vo8yyu7tdIuAujVsdbNWI+0X6xczLYIk= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jgq0R-000G3O-GP; Thu, 04 Jun 2020 14:34:03 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH 0/3] kvm: arm64: Pointer Authentication handling fixes Date: Thu, 4 Jun 2020 14:33:51 +0100 Message-Id: <20200604133354.1279412-1-maz@kernel.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kernel-team@android.com, 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 I recently discovered that the Pointer Authentication (PtrAuth) handling code in KVM is busted, and has been for a while. The main issue is that the we save the host's keys from a preemptible context. Things will go wrong at some point. In order to address this, the first patch move the saving of the host's keys to vcpu_load(). It is done eagerly, which is a bore, but is at least safe. This is definitely stable material. The following two patches are adding an optimisation and a fix for a corner case: we handle key saving and HCR massaging as a fixup, much like the FPSIMD code. This subsequently allows us to deal with the ugly case of a guest enabling PtrAuth despite it not being advertised, resulting in PAC instructions UNDEF'ing while they should be NOPs. This has been very lightly tested on a model. Marc Zyngier (3): KVM: arm64: Save the host's PtrAuth keys in non-preemptible context KVM: arm64: Handle PtrAuth traps early KVM: arm64: Enforce PtrAuth being disabled if not advertized arch/arm64/include/asm/kvm_emulate.h | 6 --- arch/arm64/kvm/arm.c | 3 +- arch/arm64/kvm/handle_exit.c | 38 --------------- arch/arm64/kvm/hyp/switch.c | 73 ++++++++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 13 ++--- 5 files changed, 80 insertions(+), 53 deletions(-) -- 2.26.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm