From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4DEE72111; Tue, 1 Apr 2025 05:14:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743484487; cv=none; b=hBAw7NTPUhfNdr7XVIeWtaQrX1z2t6Hc9jY6au2QNENDzziCJ5/xL1ajM/tY8gXtZM9ajoGapG4J3VXFEkWgwcVIOUslmWV2zTWFd4ayKqDbvB4M71V+j3ect0GtymkKjuVMpGN/UluJuyc00r7TlPdSViPbjq2cNNIfQ5j5DGE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743484487; c=relaxed/simple; bh=L4FrkKu0168YmHHVcoVFsbWR9Sf3R8pkxT3Lnke5KJM=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=kq0BZkUZj+rKs/heVI0z4MoitmLUM28mox3pFFb+vX5ZSVpSDbdu5AP8n2zA4s8WbQ+A77+l4VWlPn3qdUUDUjaRrK1s6gpQA3wBzmYVqMI7zCN7UXOzu1XLdm0L3AWrACoKkoVZL8dZ9QgH/XAmtFSBLCHLUyhmDQbvxiZZgZc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=kDAtkLct; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="kDAtkLct" Received: from [127.0.0.1] ([76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 5315DrPW3571921 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Mon, 31 Mar 2025 22:13:53 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 5315DrPW3571921 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025032001; t=1743484436; bh=fXArKFGaxt8nFnaWBdSW+pU45Be8cuJJXPIK/BFyt00=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=kDAtkLct4ESsM95J+GAXm6Ip9nS2vCeNnpZd5bqqzetTLzyI1dGpO4FHTdCywuUb7 WGNeXx4i+jLpuQrfsgKmAO//REzlRpcJIhlg3BiQafg1GzI6ikQM3j7rveeHHx8qEQ CWx/fzNgtVCbn/YdOsKRTX3+ivqNDh7QpvYGnD8XTDDfehr8TQnDZRQ5T6cB2w2NXq sNL/9PBtrg1oFPYF0fJT9aZRbEjTs4UCCHnnJFtzzQgDFxprnhDKMIRSwjt3dTD6q1 Lo7DVLOnslrIY9K+rdbbOdFCWR3dM3o3/+miqBEdIWuSpByt20GZTiNiujHjtNVCBm M4aSJPmJLqUXA== Date: Mon, 31 Mar 2025 22:13:51 -0700 From: "H. Peter Anvin" To: Andrew Cooper , "Xin Li (Intel)" , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, linux-edac@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-ide@vger.kernel.org, linux-pm@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev CC: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, jgross@suse.com, peterz@infradead.org, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, wei.liu@kernel.org, ajay.kaher@broadcom.com, alexey.amakhalov@broadcom.com, bcm-kernel-feedback-list@broadcom.com, tony.luck@intel.com, pbonzini@redhat.com, vkuznets@redhat.com, seanjc@google.com, luto@kernel.org, boris.ostrovsky@oracle.com, kys@microsoft.com, haiyangz@microsoft.com, decui@microsoft.com Subject: =?US-ASCII?Q?Re=3A_=5BRFC_PATCH_v1_01/15=5D_x86/msr=3A_Re?= =?US-ASCII?Q?place_=5F=5Fwrmsr=28=29_with_native=5Fwrmsrl=28=29?= User-Agent: K-9 Mail for Android In-Reply-To: <0da43a86-81b0-4388-b47b-3a76b15f2a4c@citrix.com> References: <20250331082251.3171276-1-xin@zytor.com> <20250331082251.3171276-2-xin@zytor.com> <0da43a86-81b0-4388-b47b-3a76b15f2a4c@citrix.com> Message-ID: <03874E9B-FAEB-4ACA-B13D-0BED7D54F443@zytor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On March 31, 2025 2:45:43 PM PDT, Andrew Cooper wrote: >On 31/03/2025 9:22 am, Xin Li (Intel) wrote: >> __wrmsr() is the lowest level primitive MSR write API, and its direct >> use is NOT preferred=2E Use its wrapper function native_wrmsrl() inste= ad=2E >> >> No functional change intended=2E >> >> Signed-off-by: Xin Li (Intel) > >The critical piece of information you're missing from the commit message >is that the MSR_IMM instructions take a single u64=2E > >Therefore to use them, you've got to arrange for all callers to provide >a single u64, rather than a split u32 pair=2E > >~Andrew That being said, there is nothing wrong with having a two-word convenience= wrapper=2E