From patchwork Tue Nov 28 11:57:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zenghui Yu X-Patchwork-Id: 13471077 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4B590C4167B for ; Tue, 28 Nov 2023 11:58:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=YRsVYXj1lM3elGfpzOgSMNjHx00XusaL12N+f93NsSs=; b=M7JSH1XYT8L03W Q5Pg1Zdfd76Wdq36GzNJBhNuhZ1kti+aDenNNbJpFpNQkW5Jtadn9Uh7zQDrg5JmP5QDS//5+42EO iMdtqAV+6dEm4Mkqc4ucqpDSX31FapAs+/CfZ70DYFEkMTBX8MrqW0XlVeXYOO6dxV7cLtxxHJvMo dEyLlx8aC62QV2fPmu9g8gptIwPTKWIO8RS0GLdlGgrH1DNH9YUef2/UVeh6ZxEU8s8OVGFR41gN/ ppWxH0EuhuAAelrhrLvUrrT4YvQU/XodY1OZpwtfeVLVt7m/gmNbJI4T7so2uRbWAjl4QyR3E88ih F05ITPDkqs3/BDgTL8Lg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r7wix-005Fon-2w; Tue, 28 Nov 2023 11:57:55 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1r7wiu-005Fnp-2e for linux-arm-kernel@lists.infradead.org; Tue, 28 Nov 2023 11:57:54 +0000 Received: from kwepemm000007.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Sfgnp6tbRzLnd8; Tue, 28 Nov 2023 19:53:18 +0800 (CST) Received: from DESKTOP-8RFUVS3.china.huawei.com (10.174.185.179) by kwepemm000007.china.huawei.com (7.193.23.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 28 Nov 2023 19:57:36 +0800 From: Zenghui Yu To: , , CC: , , , , , , , Zenghui Yu Subject: [for-5.4 1/2] arm64: cpufeature: Extract capped perfmon fields Date: Tue, 28 Nov 2023 19:57:24 +0800 Message-ID: <20231128115725.964-2-yuzenghui@huawei.com> X-Mailer: git-send-email 2.23.0.windows.1 In-Reply-To: <20231128115725.964-1-yuzenghui@huawei.com> References: <20231128115725.964-1-yuzenghui@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.185.179] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemm000007.china.huawei.com (7.193.23.189) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231128_035753_071810_1F3E630D X-CRM114-Status: GOOD ( 12.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Andrew Murray commit 8e35aa642ee4dab01b16cc4b2df59d1936f3b3c2 upstream. When emulating ID registers there is often a need to cap the version bits of a feature such that the guest will not use features that the host is not aware of. For example, when KVM mediates access to the PMU by emulating register accesses. Let's add a helper that extracts a performance monitors ID field and caps the version to a given value. Fields that identify the version of the Performance Monitors Extension do not follow the standard ID scheme, and instead follow the scheme described in ARM DDI 0487E.a page D13-2825 "Alternative ID scheme used for the Performance Monitors Extension version". The value 0xF means an IMPLEMENTATION DEFINED PMU is present, and values 0x0-OxE can be treated the same as an unsigned field with 0x0 meaning no PMU is present. Signed-off-by: Andrew Murray Reviewed-by: Suzuki K Poulose [Mark: rework to handle perfmon fields] Signed-off-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Zenghui Yu --- arch/arm64/include/asm/cpufeature.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f63438474dd5..587b8a804fc7 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -449,6 +449,29 @@ cpuid_feature_extract_unsigned_field(u64 features, int field) return cpuid_feature_extract_unsigned_field_width(features, field, 4); } +/* + * Fields that identify the version of the Performance Monitors Extension do + * not follow the standard ID scheme. See ARM DDI 0487E.a page D13-2825, + * "Alternative ID scheme used for the Performance Monitors Extension version". + */ +static inline u64 __attribute_const__ +cpuid_feature_cap_perfmon_field(u64 features, int field, u64 cap) +{ + u64 val = cpuid_feature_extract_unsigned_field(features, field); + u64 mask = GENMASK_ULL(field + 3, field); + + /* Treat IMPLEMENTATION DEFINED functionality as unimplemented */ + if (val == 0xf) + val = 0; + + if (val > cap) { + features &= ~mask; + features |= (cap << field) & mask; + } + + return features; +} + static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp) { return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);