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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 8DF22C4338F for ; Mon, 2 Aug 2021 09:39:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FAD861057 for ; Mon, 2 Aug 2021 09:39:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233121AbhHBJjS (ORCPT ); Mon, 2 Aug 2021 05:39:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232966AbhHBJjR (ORCPT ); Mon, 2 Aug 2021 05:39:17 -0400 Received: from mail-ot1-x335.google.com (mail-ot1-x335.google.com [IPv6:2607:f8b0:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50B75C06175F for ; Mon, 2 Aug 2021 02:39:08 -0700 (PDT) Received: by mail-ot1-x335.google.com with SMTP id o2-20020a9d22020000b0290462f0ab0800so16926398ota.11 for ; Mon, 02 Aug 2021 02:39:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KIhuVO31AIHAnVi6gacSlctqNjiS0tDQNaPPnMjyEgs=; b=CkxP3OMXRT7rLbi/FFZl51CGbyjS+cUeycZ1yrPwAdMjmCFHeISe0JpzKij21Jchjq MvAe1d0WxwSfKYnIb1jc0xFIzN8HqVswmLgEE3YJRp38bPU8r/2UKvCmwqGGp0HiSgjX IGDqOxgIr3kU9YwrqodFq+cXJ+QSVM6kjGUWItG6KvmqMw3xDG+AzrRYcGkrkRjFK7rJ otiDrGnvky+wnLfJedyWkXTwUz48sxy111gyhJJe4Pd6c969o8ZixHKRWDLZi44yMv4L jF3jgEs07drqy5cd1Kb6azRN5jr3AN1qGAj3cq6dNxekSFxzjwTohMfMfJNtVNp8V+uU n/Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KIhuVO31AIHAnVi6gacSlctqNjiS0tDQNaPPnMjyEgs=; b=bolWWsRsD9RIYijsGRbfUprC8jxPjW353lJnf2YjgC+cK5Ca11aXnVftYZjmpF7Psd 4BFf9q/hE72rsLFFOyS0fpGMmuPS+qcMDGdzfFO5uMY60fFILlxgvMQP0Ua0zCLmAORf XGek0OzQkwLzQ/JlAHo50pVRQR6s3nB4BTJV90fwK9X8H3qeuQxQi6e8f277I0JAZaEX JU8ZMahc9/kcwoJo0OgY2m7L2oFZGlcRpPCh+XwITHVBFN7yba66uaGZpqRJI+NRUdO4 mBMauvZ8OTPrLjolSm8+MXWd7QrTV/BpKM43p+lFZtOfgvn0Peavpscra2oUXbv97pjj zpUA== X-Gm-Message-State: AOAM532+rF0HNsntZcQ9qczpnFPZQjnmo4VvI0dmPCCcKk5d1cW2u1ys hmchUcvIXVEVcNCbO7lv1eIgs0Ei7elx4qBBirlpFw== X-Google-Smtp-Source: ABdhPJzScvX5nNNMmBy1r7KuE//uE0B0IqSD3Z0D7k2I3N1Napre9QlekC99+TW4f+xqAoRYkCZnLm//v97AQVtdrbE= X-Received: by 2002:a05:6830:1455:: with SMTP id w21mr11200078otp.365.1627897147542; Mon, 02 Aug 2021 02:39:07 -0700 (PDT) MIME-Version: 1.0 References: <20210729132818.4091769-1-qperret@google.com> <20210729132818.4091769-9-qperret@google.com> In-Reply-To: <20210729132818.4091769-9-qperret@google.com> From: Fuad Tabba Date: Mon, 2 Aug 2021 11:38:31 +0200 Message-ID: Subject: Re: [PATCH v3 08/21] KVM: arm64: Don't overwrite software bits with owner id To: Quentin Perret Cc: maz@kernel.org, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, ardb@kernel.org, qwandor@google.com, dbrazdil@google.com, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Quentin, On Thu, Jul 29, 2021 at 3:28 PM Quentin Perret wrote: > > We will soon start annotating page-tables with new flags to track shared > pages and such, and we will do so in valid mappings using software bits > in the PTEs, as provided by the architecture. However, it is possible > that we will need to use those flags to annotate invalid mappings as > well in the future, similar to what we do to track page ownership in the > host stage-2. > > In order to facilitate the annotation of invalid mappings with such > flags, it would be preferable to re-use the same bits as for valid > mappings (bits [58-55]), but these are currently used for ownership > encoding. Since we have plenty of bits left to use in invalid > mappings, move the ownership bits further down the PTE to avoid the > conflict. > > Signed-off-by: Quentin Perret > --- > arch/arm64/kvm/hyp/pgtable.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 59a394d82de3..1ee1168ac32d 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -46,7 +46,7 @@ > KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ > KVM_PTE_LEAF_ATTR_HI_S2_XN) > > -#define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) > +#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) > #define KVM_MAX_OWNER_ID 1 This change makes sense so that the same bits can be used to track sharing. Reviewed-by: Fuad Tabba Thanks, /fuad > > struct kvm_pgtable_walk_data { > -- > 2.32.0.432.gabb21c7263-goog > 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=-13.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 03726C4320A for ; Mon, 2 Aug 2021 09:39:12 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 72798610CC for ; Mon, 2 Aug 2021 09:39:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 72798610CC Authentication-Results: mail.kernel.org; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Hi Quentin, On Thu, Jul 29, 2021 at 3:28 PM Quentin Perret wrote: > > We will soon start annotating page-tables with new flags to track shared > pages and such, and we will do so in valid mappings using software bits > in the PTEs, as provided by the architecture. However, it is possible > that we will need to use those flags to annotate invalid mappings as > well in the future, similar to what we do to track page ownership in the > host stage-2. > > In order to facilitate the annotation of invalid mappings with such > flags, it would be preferable to re-use the same bits as for valid > mappings (bits [58-55]), but these are currently used for ownership > encoding. Since we have plenty of bits left to use in invalid > mappings, move the ownership bits further down the PTE to avoid the > conflict. > > Signed-off-by: Quentin Perret > --- > arch/arm64/kvm/hyp/pgtable.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 59a394d82de3..1ee1168ac32d 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -46,7 +46,7 @@ > KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ > KVM_PTE_LEAF_ATTR_HI_S2_XN) > > -#define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) > +#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) > #define KVM_MAX_OWNER_ID 1 This change makes sense so that the same bits can be used to track sharing. Reviewed-by: Fuad Tabba Thanks, /fuad > > struct kvm_pgtable_walk_data { > -- > 2.32.0.432.gabb21c7263-goog > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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=-14.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 3FF5AC4338F for ; Mon, 2 Aug 2021 09:41:14 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 0A06A60EFD for ; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Quentin, On Thu, Jul 29, 2021 at 3:28 PM Quentin Perret wrote: > > We will soon start annotating page-tables with new flags to track shared > pages and such, and we will do so in valid mappings using software bits > in the PTEs, as provided by the architecture. However, it is possible > that we will need to use those flags to annotate invalid mappings as > well in the future, similar to what we do to track page ownership in the > host stage-2. > > In order to facilitate the annotation of invalid mappings with such > flags, it would be preferable to re-use the same bits as for valid > mappings (bits [58-55]), but these are currently used for ownership > encoding. Since we have plenty of bits left to use in invalid > mappings, move the ownership bits further down the PTE to avoid the > conflict. > > Signed-off-by: Quentin Perret > --- > arch/arm64/kvm/hyp/pgtable.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 59a394d82de3..1ee1168ac32d 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -46,7 +46,7 @@ > KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ > KVM_PTE_LEAF_ATTR_HI_S2_XN) > > -#define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) > +#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) > #define KVM_MAX_OWNER_ID 1 This change makes sense so that the same bits can be used to track sharing. Reviewed-by: Fuad Tabba Thanks, /fuad > > struct kvm_pgtable_walk_data { > -- > 2.32.0.432.gabb21c7263-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel