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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 44898C04AA5 for ; Mon, 15 Oct 2018 12:05:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C08E2064A for ; Mon, 15 Oct 2018 12:05:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C08E2064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726594AbeJOTuD (ORCPT ); Mon, 15 Oct 2018 15:50:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35992 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726319AbeJOTuD (ORCPT ); Mon, 15 Oct 2018 15:50:03 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BD6E33082143; Mon, 15 Oct 2018 12:05:02 +0000 (UTC) Received: from [10.36.117.209] (ovpn-117-209.ams2.redhat.com [10.36.117.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 54B8867C70; Mon, 15 Oct 2018 12:04:48 +0000 (UTC) Subject: Re: [PATCH V4 00/15] x86/KVM/Hyper-v: Add HV ept tlb range flush hypercall support in KVM To: lantianyu1986@gmail.com Cc: Lan Tianyu , benh@kernel.crashing.org, catalin.marinas@arm.com, christoffer.dall@arm.com, devel@linuxdriverproject.org, haiyangz@microsoft.com, hpa@zytor.com, jhogan@kernel.org, kvmarm@lists.cs.columbia.edu, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, kys@microsoft.com, linux-arm-kernel@lists.infradead.org, linux@armlinux.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, marc.zyngier@arm.com, mingo@redhat.com, mpe@ellerman.id.au, paul.burton@mips.com, paulus@ozlabs.org, ralf@linux-mips.org, rkrcmar@redhat.com, sthemmin@microsoft.com, tglx@linutronix.de, will.deacon@arm.com, x86@kernel.org, michael.h.kelley@microsoft.com, vkuznets@redhat.com References: <20181013145406.4911-1-Tianyu.Lan@microsoft.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20181013145406.4911-1-Tianyu.Lan@microsoft.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Mon, 15 Oct 2018 12:05:03 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/10/2018 16:53, lantianyu1986@gmail.com wrote: > From: Lan Tianyu > > For nested memory virtualization, Hyper-v doesn't set write-protect > L1 hypervisor EPT page directory and page table node to track changes > while it relies on guest to tell it changes via HvFlushGuestAddressLlist > hypercall. HvFlushGuestAddressLlist hypercall provides a way to flush > EPT page table with ranges which are specified by L1 hypervisor. > > If L1 hypervisor uses INVEPT or HvFlushGuestAddressSpace hypercall to > flush EPT tlb, Hyper-V will invalidate associated EPT shadow page table > and sync L1's EPT table when next EPT page fault is triggered. > HvFlushGuestAddressLlist hypercall helps to avoid such redundant EPT > page fault and synchronization of shadow page table. So I just told you that the first part is well understood but I must retract that; after carefully reviewing the whole series, I think one of us is actually very confused. I am not afraid to say it can be me, but my understanding is that you're passing L1 GPAs to the hypercall and instead the spec says it expects L2 GPAs. (Consider that, because KVM's shadow paging code is shared between nested EPT and !EPT cases, every time you see gpa/gfn in the code it is for L1, while nested EPT GPAs are really what the code calls gva.) What's going on? Paolo