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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E8B96C3DA42 for ; Mon, 8 Jul 2024 16:28:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UNGVYq6CTRRjU2l3olu7LiTjEXr9Jn7ouCVvv46ZH0k=; b=NF3nMy+vXjNB4bFwMgek7UybmT Irlry3XxmqIgp6oJFrvXA38XrIR734/F3z59zXO0DXOnEcHRps+xCOnx8WtFKb8PuK96b3dMjjgnu 56GQP0NdyC6Y0pFR4R3c6XjjS5bPKcNl/v09MhucUzrlofT+hP1nu4/uUIIOD42/JWq8/9wS1zSNS 6vuE9bbJ06E4eG60ZMsW5PW791JL/I0rYOLd3OSF0LCzAn11P0HADgrVh7Nj0m7/Vn6s2ISGLVlmu hvPS+5UfbHBdNpR9yAyU5vUyWIypxtJOI75YajObxWSDL/QVTtpXK//5CSZtrwwjtPDMIxr6K9dHR spAOD5Ag==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sQrEB-00000004RDE-0wdK; Mon, 08 Jul 2024 16:28:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sQrDu-00000004R8U-2qsl for linux-arm-kernel@lists.infradead.org; Mon, 08 Jul 2024 16:28:21 +0000 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 14C3A1042; Mon, 8 Jul 2024 09:28:41 -0700 (PDT) Received: from arm.com (e121798.manchester.arm.com [10.32.101.22]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 77F323F641; Mon, 8 Jul 2024 09:28:14 -0700 (PDT) Date: Mon, 8 Jul 2024 17:28:11 +0100 From: Alexandru Elisei To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Joey Gouly Subject: Re: [PATCH 00/12] KVM: arm64: nv: Add support for address translation instructions Message-ID: References: <20240625133508.259829-1-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240625133508.259829-1-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240708_092818_960154_3243FBE6 X-CRM114-Status: GOOD ( 25.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Marc, On Tue, Jun 25, 2024 at 02:34:59PM +0100, Marc Zyngier wrote: > Another task that a hypervisor supporting NV on arm64 has to deal with > is to emulate the AT instruction, because we multiplex all the S1 > translations on a single set of registers, and the guest S2 is never > truly resident on the CPU. > > So given that we lie about page tables, we also have to lie about > translation instructions, hence the emulation. Things are made > complicated by the fact that guest S1 page tables can be swapped out, > and that our shadow S2 is likely to be incomplete. So while using AT > to emulate AT is tempting (and useful), it is not going to always > work, and we thus need a fallback in the shape of a SW S1 walker. > > This series is built in 4 basic blocks: > > - Add missing definition and basic reworking > > - Dumb emulation of all relevant AT instructions using AT instructions > > - Add a SW S1 walker that is using our S2 walker I wanted to have a look at the S1 walker, and in my inbox I only have patches #1 to #9 ("KVM: arm64: nv: Make ps_to_output_size() generally available"). Checked on the kvm mailing list archive [1], same thing; a google search for the string "KVM: arm64: nv: Add SW walker for AT S1 emulation" (quotes included) turns up the cover letter. Am I looking in the wrong places? [1] https://www.spinics.net/lists/kvm/msg351826.html Thanks, Alex > > - Add FEAT_ATS1A support, which is almost trivial > > This has been tested by comparing the output of a HW walker with the > output of the SW one. Obviously, this isn't bullet proof, and I'm > pretty sure there are some nasties in there. > > In a departure from my usual habit, this series is on top of > kvmarm/next, as it depends on the NV S2 shadow code. > > Joey Gouly (1): > KVM: arm64: make kvm_at() take an OP_AT_* > > Marc Zyngier (11): > arm64: Add missing APTable and TCR_ELx.HPD masks > arm64: Add PAR_EL1 field description > KVM: arm64: nv: Turn upper_attr for S2 walk into the full descriptor > KVM: arm64: nv: Honor absence of FEAT_PAN2 > KVM: arm64: nv: Add basic emulation of AT S1E{0,1}{R,W}[P] > KVM: arm64: nv: Add basic emulation of AT S1E2{R,W} > KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W} > KVM: arm64: nv: Make ps_to_output_size() generally available > KVM: arm64: nv: Add SW walker for AT S1 emulation > KVM: arm64: nv: Plumb handling of AT S1* traps from EL2 > KVM: arm64: nv: Add support for FEAT_ATS1A > > arch/arm64/include/asm/kvm_arm.h | 1 + > arch/arm64/include/asm/kvm_asm.h | 6 +- > arch/arm64/include/asm/kvm_nested.h | 18 +- > arch/arm64/include/asm/pgtable-hwdef.h | 7 + > arch/arm64/include/asm/sysreg.h | 19 + > arch/arm64/kvm/Makefile | 2 +- > arch/arm64/kvm/at.c | 1007 ++++++++++++++++++++++++ > arch/arm64/kvm/emulate-nested.c | 2 + > arch/arm64/kvm/hyp/include/hyp/fault.h | 2 +- > arch/arm64/kvm/nested.c | 26 +- > arch/arm64/kvm/sys_regs.c | 60 ++ > 11 files changed, 1125 insertions(+), 25 deletions(-) > create mode 100644 arch/arm64/kvm/at.c > > -- > 2.39.2 > >