From patchwork Tue Aug 1 00:21:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mingwei Zhang X-Patchwork-Id: 13335624 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56DECC04E69 for ; Tue, 1 Aug 2023 00:21:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231280AbjHAAVv (ORCPT ); Mon, 31 Jul 2023 20:21:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231421AbjHAAVm (ORCPT ); Mon, 31 Jul 2023 20:21:42 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 762061BC9 for ; Mon, 31 Jul 2023 17:21:39 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d0d27cd9db9so9401245276.0 for ; Mon, 31 Jul 2023 17:21:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690849298; x=1691454098; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=lAQnhGDOkYRMbkZrdC3SL5zoWbQR4X7L8Yn3+Vr770Y=; b=mSlCLmLdSdPxkircK3iN8jwT5W5vP1eDs51MN2JElm1ENf0E0zV1+hxVIqVpBj8Lbq 3YbA2/WyG5K4xCuq9Coj3iUMdMibr4FQcUpL6vKn/cEb0mcK+XtbQBYhpoD1utE9R/hw sNnyB6mq7sHFk+jZtZuvaN58hRjds+AE8Y+onHTyMUrpDQcsvWZDQTAAoX0qYG6i2kei BlqqustZeYnIPg8lYc6HCZmKcoW3EI/AsWv3P+mg4OOKdmJfb1bjcImHHRWilDTHx0WD OiGbBfE4+wE/VlffLCEkwsxzLb7nSfkAHH9Dkh8+py9OmsUsIBcfhvxGec3zqaWc+OQH 1g3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690849298; x=1691454098; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=lAQnhGDOkYRMbkZrdC3SL5zoWbQR4X7L8Yn3+Vr770Y=; b=DVLvdwqRBoBMLp1mUp1YppAMHz6bL14tO+0RA5k5daN4y9cfxXR7R46ka127rJTwRI BAKOUB5Lqy4EhTngbXey8ePbu2hPLhGCo2yECW1rWeP8eqmM/riVRsTjcmvIcq2K4dXf u8DDKIrHH3RNiSFYX9spe0be0mkhk2PJrEDdtoQ2lNQrlKYYpcbLQixpteskfeMSYWxj y2ct56MvIAQ++TXEbclpLrHgiksiy6P4lysP9Fa9zd1X7O7nLDhh3mvHH2I28hbiilfd 82+1wdyZbvmp7UAW0F8SU8mNekB+OxfIsThlxMJl8v0dP899YPJOGBsYBfOmZA8plWff /Jeg== X-Gm-Message-State: ABy/qLYvb45Cst5cQXWzzY4i+JVz61BGxew6m7ahwvkQo2uY5pK6qPfi 9QXTzVt+wcwHs2XODRiwefioN/lMUBNV X-Google-Smtp-Source: APBJJlEbXDgaPfEPE0+Rh+gqu5EcA7wjOaPwSG51qBZAvMseTavHv77hIuRMa7UCmBrdjjzh7UNZF7RaBIf5 X-Received: from mizhang-super.c.googlers.com ([34.105.13.176]) (user=mizhang job=sendgmr) by 2002:a25:dfc3:0:b0:d15:53b5:509f with SMTP id w186-20020a25dfc3000000b00d1553b5509fmr119752ybg.2.1690849298640; Mon, 31 Jul 2023 17:21:38 -0700 (PDT) Reply-To: Mingwei Zhang Date: Tue, 1 Aug 2023 00:21:25 +0000 In-Reply-To: <20230801002127.534020-1-mizhang@google.com> Mime-Version: 1.0 References: <20230801002127.534020-1-mizhang@google.com> X-Mailer: git-send-email 2.41.0.585.gd2178a4bd4-goog Message-ID: <20230801002127.534020-6-mizhang@google.com> Subject: [PATCH v3 5/6] KVM: Documentation: Add the missing description for mmu_valid_gen into kvm_mmu_page From: Mingwei Zhang To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mingwei Zhang , Kai Huang , Jim Mattson , David Matlack , Ben Gardon , Xu Yilun , Zhi Wang , Randy Dunlap Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add the description for mmu_valid_gen into kvm_mmu_page description. mmu_valid_gen is used in shadow MMU for fast zapping. Update the doc to reflect that. Signed-off-by: Mingwei Zhang Reviewed-by: Kai Huang --- Documentation/virt/kvm/x86/mmu.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst index 40daf8beb9b1..581e53fa00a2 100644 --- a/Documentation/virt/kvm/x86/mmu.rst +++ b/Documentation/virt/kvm/x86/mmu.rst @@ -208,6 +208,16 @@ Shadow pages contain the following information: The page is not backed by a guest page table, but its first entry points to one. This is set if NPT uses 5-level page tables (host CR4.LA57=1) and is shadowing L1's 4-level NPT (L1 CR4.LA57=1). + mmu_valid_gen: + The MMU generation of this page, used to fast zap of all MMU pages within a + VM without blocking vCPUs. Specifically, KVM updates the per-VM valid MMU + generation which causes the mismatch of mmu_valid_gen for each mmu page. + This makes all existing MMU pages obsolete. Obsolete pages can't be used. + Therefore, vCPUs must load a new, valid root before re-entering the guest. + The MMU generation is only ever '0' or '1'. Note, the TDP MMU doesn't use + this field as non-root TDP MMU pages are reachable only from their owning + root. Thus it suffices for TDP MMU to use role.invalid in root pages to + invalidate all MMU pages. gfn: Either the guest page table containing the translations shadowed by this page, or the base page frame for linear translations. See role.direct.