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 6BB7B2857E3; Fri, 11 Apr 2025 20:52:12 +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=1744404734; cv=none; b=gKIivrK99KlmnuQqS6T9y6B+g0NRg4zCi2N+H2Rvi5U2xoz1JmBYrkSwfydllclTPngXazdwuLLu/hXvIp9QAt8z3U1IEmsn3+A6tda56xaBD9Y7flznimh0ztDsnFxv5i1O2RyxrDELbTRIOmNK6rc/wmeaLySwgADS05VnKEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744404734; c=relaxed/simple; bh=kxTCj2K40xus1IkV+DNiWTNVByJ6Z3Ovx9rtSTGdTRk=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=ozyC7CivqUL25/ybZe33nFUC8jejRF3xi5PVIuPIu22b8qheLCU87KN3l6O9Mer1VbeaEVyNSbfVz3M9ELXf+OitH9J/3uyn/qgrdpRvUszinTBOkhkb5iPz/0BNntfuxoLOnwLWKLy91R78nhMFspvgW3bKYSAj9K6Hr092rYI= 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=MaUaGM8p; 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="MaUaGM8p" 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 53BKokUU689207 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Fri, 11 Apr 2025 13:50:46 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 53BKokUU689207 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025032001; t=1744404648; bh=RSxA6WjXfzTzp9cSLSXzWSj0aQbPDgdMx3rGgv5vZFo=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=MaUaGM8ptiyNi5JNPWt6NXDw8PAuW9ldRndGnP2Ms2a5WhDxGDZmG9wZSREChComZ 5WZ/ACqI8QPIApW2H+3S60a8ZuhEXXT3/4CoGujji3jvmFlwVOFHC9tj+gJU0zYj76 fLPUlJt1NAlnsIICrT1IBvg8ssoIvqY4BrCd0zWR2qJWd/gvqDxfJWqsioW+lcez2s 0OjBs72/2ECaksg5m8Zdd+dsabWYMF97MvLqFSlWKKuRnrqMJtIZxV9Y2X0uNN/Twt qct8mM81m1xNoj3uyJYNXFGbNRMRc88O5YTcpLTHLdVRgYOnAL34JelLSSB8abrZsj FVc2EtkpGepIg== Date: Fri, 11 Apr 2025 13:50:45 -0700 From: "H. Peter Anvin" To: Xin Li , Sean Christopherson CC: 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, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, jgross@suse.com, andrew.cooper3@citrix.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, bcm-kernel-feedback-list@broadcom.com, tony.luck@intel.com, pbonzini@redhat.com, vkuznets@redhat.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_10/15=5D_KVM=3A_VMX=3A_Use_WR?= =?US-ASCII?Q?MSRNS_or_its_immediate_form_when_available?= User-Agent: K-9 Mail for Android In-Reply-To: <41eb2d08-1b2d-4ca8-bcb7-f5f4611f91a9@zytor.com> References: <20250331082251.3171276-1-xin@zytor.com> <20250331082251.3171276-11-xin@zytor.com> <41eb2d08-1b2d-4ca8-bcb7-f5f4611f91a9@zytor.com> Message-ID: <39ECA4CA-9CBC-4F72-B52E-9BD06DBF9B6D@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 April 11, 2025 9:18:08 AM PDT, Xin Li wrote: >On 4/10/2025 4:24 PM, Sean Christopherson wrote: >>> +/* >>> + * Write EAX to MSR_IA32_SPEC_CTRL=2E >>> + * >>> + * Choose the best WRMSR instruction based on availability=2E >>> + * >>> + * Replace with 'wrmsrns' and 'wrmsrns %rax, $MSR_IA32_SPEC_CTRL' onc= e binutils support them=2E >>> + */ >>> +=2Emacro WRITE_EAX_TO_MSR_IA32_SPEC_CTRL >>> + ALTERNATIVE_2 __stringify(mov $MSR_IA32_SPEC_CTRL, %ecx; \ >>> + xor %edx, %edx; \ >>> + mov %edi, %eax; \ >>> + ds wrmsr), \ >>> + __stringify(mov $MSR_IA32_SPEC_CTRL, %ecx; \ >>> + xor %edx, %edx; \ >>> + mov %edi, %eax; \ >>> + ASM_WRMSRNS), \ >>> + X86_FEATURE_WRMSRNS, \ >>> + __stringify(xor %_ASM_AX, %_ASM_AX; \ >>> + mov %edi, %eax; \ >>> + ASM_WRMSRNS_RAX; =2Elong MSR_IA32_SPEC_CTRL), \ >>> + X86_FEATURE_MSR_IMM >>> +=2Eendm >> This is quite hideous=2E I have no objection to optimizing __vmx_vcpu_= run(), but >> I would much prefer that a macro like this live in generic code, and th= at it be >> generic=2E It should be easy enough to provide an assembly friendly eq= uivalent to >> __native_wrmsr_constant()=2E > >Will do=2E This should be coming anyway, right?