From nobody Fri Dec 19 16:59:25 2025 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 CAE8EC4332F for ; Thu, 3 Nov 2022 02:51:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230006AbiKCCvX (ORCPT ); Wed, 2 Nov 2022 22:51:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231260AbiKCCu6 (ORCPT ); Wed, 2 Nov 2022 22:50:58 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E3B313E9B; Wed, 2 Nov 2022 19:50:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667443855; x=1698979855; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=lg09VbI/60vYnXZzpwRBHqC+c64eQ+EJZudgsq58kIU=; b=WrcQQ9l7ltZb7HpcXDVAO+QcAL+f83wQBO2shMQDiR/mz68mJSf/ZIyb HxpliXC3OhCwEvE9cT8epwkCDAbFO4DwR8mZ86PRzWnDO2fj4o45XON7n 7xRo7bvSsr2PzRDvMl+pSURgq6liAbmzqtyZzRJRtJXQkReo8992iY/xr TyQIhH8+rnnMjk7VKhGYleFn+HxRY/+UbSGXryaS6VrsK0Jgg7GG/RBqO 3/4tWk7iaJ7LWuDPshDP4C3t7rIDP2pTr02aVX04TiWxY6uaexG65VIuz rrb7imCSJbnIrcdommYv+XZA3BArRVHHhjwSMXZb4LR+i4cDSd7+8d6iO g==; X-IronPort-AV: E=McAfee;i="6500,9779,10519"; a="308289844" X-IronPort-AV: E=Sophos;i="5.95,235,1661842800"; d="scan'208";a="308289844" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2022 19:50:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10519"; a="698047897" X-IronPort-AV: E=Sophos;i="5.95,235,1661842800"; d="scan'208";a="698047897" Received: from jiaxichen-precision-3650-tower.sh.intel.com ([10.239.159.75]) by fmsmga008.fm.intel.com with ESMTP; 02 Nov 2022 19:50:50 -0700 From: Jiaxi Chen To: kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, ndesaulniers@google.com, alexandre.belloni@bootlin.com, peterz@infradead.org, jpoimboe@kernel.org, chang.seok.bae@intel.com, pawan.kumar.gupta@linux.intel.com, babu.moger@amd.com, jmattson@google.com, sandipan.das@amd.com, tony.luck@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, fenghua.yu@intel.com, keescook@chromium.org, nathan@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 4/8] x86: KVM: Advertise AMX-FP16 CPUID to user space Date: Thu, 3 Nov 2022 10:50:26 +0800 Message-Id: <20221103025030.78371-5-jiaxi.chen@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221103025030.78371-1-jiaxi.chen@linux.intel.com> References: <20221103025030.78371-1-jiaxi.chen@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Latest Intel platform Granite Rapids has introduced a new instruction - AMX-FP16, which performs dot-products of two FP16 tiles and accumulates the results into a packed single precision tile. This instrucion needs no additional enabling on top of the existing kernel AMX enabling. AMX-FP16 adds FP16 capability and also allows a FP16 GPU trained model to run faster without loss of accuracy or added SW overhead. The bit definition: CPUID.(EAX=3D7,ECX=3D1):EAX[bit 21] This CPUID is exposed to user space. Besides, there is no other VMX control for this instruction. Signed-off-by: Jiaxi Chen --- arch/x86/kvm/cpuid.c | 2 +- arch/x86/kvm/reverse_cpuid.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b388ef52f8c8..19ef02d5b11b 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -657,7 +657,7 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD); =20 kvm_cpu_cap_init_scattered(CPUID_7_1_EAX, - F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) + F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) | F(AMX_FP16) ); =20 kvm_cpu_cap_mask(CPUID_D_1_EAX, diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h index 24f570ddb225..05fd43ebd226 100644 --- a/arch/x86/kvm/reverse_cpuid.h +++ b/arch/x86/kvm/reverse_cpuid.h @@ -29,6 +29,7 @@ enum kvm_only_cpuid_leafs { #define X86_FEATURE_AVX_VNNI KVM_X86_FEATURE(CPUID_7_1_EAX, 4) #define X86_FEATURE_AVX512_BF16 KVM_X86_FEATURE(CPUID_7_1_EAX, 5) #define X86_FEATURE_CMPCCXADD KVM_X86_FEATURE(CPUID_7_1_EAX, 7) +#define X86_FEATURE_AMX_FP16 KVM_X86_FEATURE(CPUID_7_1_EAX, 21) =20 struct cpuid_reg { u32 function; --=20 2.27.0