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 1643BCD80AD for ; Tue, 10 Oct 2023 11:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231431AbjJJLfO (ORCPT ); Tue, 10 Oct 2023 07:35:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231231AbjJJLfN (ORCPT ); Tue, 10 Oct 2023 07:35:13 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3D50A4; Tue, 10 Oct 2023 04:35:11 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9AB1C433C8; Tue, 10 Oct 2023 11:35:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696937711; bh=Dgl0erwYB9qFKvNeOVGhClGJ2XJSfTqlW8vQXJ16jwE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lo18jUpaQDYGWwjRo5pwiCs8yx9ipILrzsSMZQ0R0MKZzc6ICJSPpb+hEl5NdWk4K XoSQaYMpxaNs78W/9Vqy2uDV4djSIQUaE8o+k8DgbLH3Ze2Eu8AgM5LRcwXhDZsX2z g/o6YR/zmdh2S04QblPAcSQ879RY7ZPv2YrU0p6c= Date: Tue, 10 Oct 2023 13:35:08 +0200 From: Greg KH To: =?iso-8859-1?Q?Jos=E9?= Pekkarinen Cc: seanjc@google.com, pbonzini@redhat.com, skhan@linuxfoundation.org, dave.hansen@linux.intel.com, kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, tglx@linutronix.de, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH] kvm/sev: make SEV/SEV-ES asids configurable Message-ID: <2023101050-scuff-overstay-9b43@gregkh> References: <20231010100441.30950-1-jose.pekkarinen@foxhound.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231010100441.30950-1-jose.pekkarinen@foxhound.fi> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Oct 10, 2023 at 01:04:39PM +0300, José Pekkarinen wrote: > There are bioses that doesn't allow to configure the > number of asids allocated for SEV/SEV-ES, for those > cases, the default behaviour allocates all the asids > for SEV, leaving no room for SEV-ES to have some fun. "fun"? Also, please use the full 72 columns for your changelog. > If the user request SEV-ES to be enabled, it will > find the kernel just run out of resources and ignored > user request. This following patch will address this > issue by making the number of asids for SEV/SEV-ES > configurable over kernel module parameters. > > Signed-off-by: José Pekkarinen > --- > arch/x86/kvm/svm/sev.c | 28 +++++++++++++++++++++++----- > 1 file changed, 23 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 07756b7348ae..68a63b42d16a 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -51,9 +51,18 @@ > static bool sev_enabled = true; > module_param_named(sev, sev_enabled, bool, 0444); > > +/* nr of asids requested for SEV */ > +static unsigned int requested_sev_asids; > +module_param_named(sev_asids, requested_sev_asids, uint, 0444); > + > /* enable/disable SEV-ES support */ > static bool sev_es_enabled = true; > module_param_named(sev_es, sev_es_enabled, bool, 0444); > + > +/* nr of asids requested for SEV-ES */ > +static unsigned int requested_sev_es_asids; > +module_param_named(sev_es_asids, requested_sev_asids, uint, 0444); Why more module parameters? Why can't this "just work" properly without forcing a user to make manual changes? This isn't the 1990's anymore. > + > #else > #define sev_enabled false > #define sev_es_enabled false > @@ -2194,6 +2203,11 @@ void __init sev_hardware_setup(void) > if (!max_sev_asid) > goto out; > > + if (requested_sev_asids + requested_sev_es_asids > max_sev_asid) { > + pr_info("SEV asids requested more than available: %u ASIDs\n", max_sev_asid); Why isn't this an error? thanks, greg k-h