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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 D439AC433E1 for ; Tue, 26 May 2020 13:41:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B34A62068D for ; Tue, 26 May 2020 13:41:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389121AbgEZNl2 (ORCPT ); Tue, 26 May 2020 09:41:28 -0400 Received: from foss.arm.com ([217.140.110.172]:51028 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388963AbgEZNlY (ORCPT ); Tue, 26 May 2020 09:41:24 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 46420101E; Tue, 26 May 2020 06:41:23 -0700 (PDT) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C60BE3F6C4; Tue, 26 May 2020 06:41:21 -0700 (PDT) From: James Morse To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , Babu Moger , James Morse Subject: [PATCH v4 07/10] x86/resctrl: Add arch_needs_linear to explain AMD/Intel MBA difference Date: Tue, 26 May 2020 14:40:56 +0100 Message-Id: <20200526134059.1690-8-james.morse@arm.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20200526134059.1690-1-james.morse@arm.com> References: <20200526134059.1690-1-james.morse@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The configuration values user-space provides to the resctrl filesystem are ABI. To make this work on another architecture we want to move all the ABI bits out of /arch/x86 and under /fs. To do this, the differences between AMD and Intel CPUs needs to be explained to resctrl via resource properties, instead of function pointers that let the arch code accept subtly different values on different platforms/architectures. For MBA, Intel CPUs reject configuration attempts for non-linear resources, whereas AMD ignore this field as its MBA resource is never linear. To merge the parse/validate functions we need to explain this difference. Add arch_needs_linear to indicate the arch code needs the linear property to be true to configure this resource. AMD can set this and delay_linear to false. Intel can set arch_needs_linear to true to keep the existing "No support for non-linear MB domains" error message for affected platforms. Signed-off-by: James Morse Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger --- An alternative to this is for Intel non-linear MBA resources to clear alloc_capable as they can't be configured anyway. --- arch/x86/kernel/cpu/resctrl/core.c | 3 +++ arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 8 +++++++- arch/x86/kernel/cpu/resctrl/internal.h | 2 ++ 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index e1fed3928b59..c6b73b0ee070 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -260,6 +260,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r) r->num_closid = edx.split.cos_max + 1; max_delay = eax.split.max_delay + 1; r->default_ctrl = MAX_MBA_BW; + r->membw.arch_needs_linear = true; if (ecx & MBA_IS_LINEAR) { r->membw.delay_linear = true; r->membw.min_bw = MAX_MBA_BW - max_delay; @@ -267,6 +268,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r) } else { if (!rdt_get_mb_table(r)) return false; + r->membw.arch_needs_linear = false; } r->data_width = 3; @@ -288,6 +290,7 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r) /* AMD does not use delay */ r->membw.delay_linear = false; + r->membw.arch_needs_linear = false; r->membw.min_bw = 0; r->membw.bw_gran = 1; diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index 934c8fb8a64a..e3bcd77add2b 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -33,6 +33,12 @@ static bool bw_validate_amd(char *buf, unsigned long *data, unsigned long bw; int ret; + /* temporary: always false on AMD */ + if (!r->membw.delay_linear && r->membw.arch_needs_linear) { + rdt_last_cmd_puts("No support for non-linear MB domains\n"); + return false; + } + ret = kstrtoul(buf, 10, &bw); if (ret) { rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf); @@ -82,7 +88,7 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r) /* * Only linear delay values is supported for current Intel SKUs. */ - if (!r->membw.delay_linear) { + if (!r->membw.delay_linear && r->membw.arch_needs_linear) { rdt_last_cmd_puts("No support for non-linear MB domains\n"); return false; } diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index dd51e23e346b..cc72ba415c3d 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -371,6 +371,7 @@ struct rdt_cache { * @min_bw: Minimum memory bandwidth percentage user can request * @bw_gran: Granularity at which the memory bandwidth is allocated * @delay_linear: True if memory B/W delay is in linear scale + * @arch_needs_linear: True if we can't configure non-linear resources * @mba_sc: True if MBA software controller(mba_sc) is enabled * @mb_map: Mapping of memory B/W percentage to memory B/W delay */ @@ -378,6 +379,7 @@ struct rdt_membw { u32 min_bw; u32 bw_gran; u32 delay_linear; + bool arch_needs_linear; bool mba_sc; u32 *mb_map; }; -- 2.19.1