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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 868BCC28D13 for ; Tue, 23 Aug 2022 00:24:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239089AbiHWAYp (ORCPT ); Mon, 22 Aug 2022 20:24:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237871AbiHWAYm (ORCPT ); Mon, 22 Aug 2022 20:24:42 -0400 Received: from mail-yw1-x1135.google.com (mail-yw1-x1135.google.com [IPv6:2607:f8b0:4864:20::1135]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76EBF3DF1A for ; Mon, 22 Aug 2022 17:24:36 -0700 (PDT) Received: by mail-yw1-x1135.google.com with SMTP id 00721157ae682-3378303138bso298948557b3.9 for ; Mon, 22 Aug 2022 17:24:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc; bh=6+1zWJmH8QXj8X4FXqMGXd6ZgOyPA1Adef25hUn+KAU=; b=PWiv/pt0eSkF0f8mONhhv3hdl89iPmgPtUC9QM8RGL1OWPKWRZ9wY0lMUjFTEUMKsc 3hM5t30SApCzUy1DygscsE6x4XTmaiZlcEChFHEzbWyVLKdxNuA0HivzYEWnIaveOxS8 WEnphSUR3k+YjfElipFI3Yttz7grHqKyX6Yay4WoEwNpeicYVWtNkvVrIjF/ckciDzAM YBQjrMSrBtQcEsc9P9jW2lVqPXyLKT0sNFcXB3wIbvizqxm1xU8rTANVDZ0PKLsL+W5S NmIdB+O3irgvNYyWgb5v0ggWJHpOfCuI5Xg2QLVo327IF3nUVJO8p28HohVdXD8W6AGe ik0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=6+1zWJmH8QXj8X4FXqMGXd6ZgOyPA1Adef25hUn+KAU=; b=X/fYd0Qlgk3DSC28FB8Lt6ebVmGKNzW30q6SJiSHaqz8HMbABfPoZK3MEug2zooIGk CBOR+w09zOqKjIbrU+mKnL5NCoY+Qv8+WgBgMoEW37BkLtBpwMXG+l7QSUwC1RTDyoGZ 1lCLm/8lZZmLaMr2ZkjgPaIvfMeBXEv7db+QZHJ33j1+tpDpZJQPoZKM2PSxdW2ODl+u 81JNpxJ0Lar+ldufuBHlw4uI8PKwb/7GxwLwKTnbG5xjtAQ+DVNOo8mKXe0cUh/7PNd4 LvqUKW8WXRBzkD+coswNCQLctWL09oTSs3PMoA37+MNjAVWtJ25qmPqSyxbiXCgo870f eTGw== X-Gm-Message-State: ACgBeo0NAWZYeHo0Yyd1YUX6jugnp0fIvIiaeisSfl3d2GiW5Yhj8HtM WqHvF04l5T2nlnoVdCaikreOIdxXdHvo9sE3KklgoA== X-Google-Smtp-Source: AA6agR6yvCKBCw+9E6wATTIinr+YX84YW2LwjVVwyCqtO3HtSsO1BKM6CnGmBMZ5AHNoc00BYjO2CRpOe4a5YC191gw= X-Received: by 2002:a25:40c5:0:b0:694:e710:a26 with SMTP id n188-20020a2540c5000000b00694e7100a26mr17417813yba.509.1661214275620; Mon, 22 Aug 2022 17:24:35 -0700 (PDT) MIME-Version: 1.0 References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com> <44495aa8acb666b447a08a1c3af80987aa3cea3a.1659103274.git.thomas.lendacky@amd.com> In-Reply-To: <44495aa8acb666b447a08a1c3af80987aa3cea3a.1659103274.git.thomas.lendacky@amd.com> From: Dionna Amalie Glaze Date: Mon, 22 Aug 2022 17:24:24 -0700 Message-ID: Subject: Re: [PATCH v1 2/2] x86/sev: Add SNP-specific unaccepted memory support To: Tom Lendacky Cc: LKML , "the arch/x86 maintainers" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "Kirill A. Shutemov" , "H. Peter Anvin" , Michael Roth , Joerg Roedel , Andy Lutomirski , Peter Zijlstra Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > +void snp_accept_memory(phys_addr_t start, phys_addr_t end) > +{ > + unsigned long vaddr; > + unsigned int npages; > + > + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) > + return; > + > + vaddr = (unsigned long)__va(start); > + npages = (end - start) >> PAGE_SHIFT; > + > + set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); > + > + pvalidate_pages(vaddr, npages, true); > +} My testing of this patch shows that a significant amount of time is spent using the MSR protocol to change page state, in such a significant fashion that it's slower than eagerly accepting all memory. The difference gets worse as the RAM size goes up, so I think there's some phase problem with the GHCB protocol not getting used early enough? -- -Dionna Glaze, PhD (she/her)