From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756402AbdEUDTT (ORCPT ); Sat, 20 May 2017 23:19:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:41200 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755306AbdEUDTS (ORCPT ); Sat, 20 May 2017 23:19:18 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E1D423960 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org Subject: Re: [PATCH v3 04/10] x86/hyper-v: fast hypercall implementation To: Vitaly Kuznetsov , devel@linuxdriverproject.org Cc: Stephen Hemminger , Jork Loeser , Haiyang Zhang , x86@kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner References: <20170519140953.1167-1-vkuznets@redhat.com> <20170519140953.1167-5-vkuznets@redhat.com> From: Andy Lutomirski Message-ID: <1fa6d42d-0f2d-2db6-47ad-d1ae06e13f02@kernel.org> Date: Sat, 20 May 2017 20:18:15 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 MIME-Version: 1.0 In-Reply-To: <20170519140953.1167-5-vkuznets@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-MW Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/19/2017 07:09 AM, Vitaly Kuznetsov wrote: > Hyper-V supports 'fast' hypercalls when all parameters are passed through > registers. Implement an inline version of a simpliest of these calls: > hypercall with one 8-byte input and no output. > > Proper hypercall input interface (struct hv_hypercall_input) definition is > added as well. > > Signed-off-by: Vitaly Kuznetsov > Acked-by: K. Y. Srinivasan > Tested-by: Simon Xiao > Tested-by: Srikanth Myakam > --- > arch/x86/include/asm/mshyperv.h | 39 ++++++++++++++++++++++++++++++++++++++ > arch/x86/include/uapi/asm/hyperv.h | 19 +++++++++++++++++++ > 2 files changed, 58 insertions(+) > > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index e293937..028e29b 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -216,6 +216,45 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output) > #endif /* !x86_64 */ > } > > +/* Fast hypercall with 8 bytes of input and no output */ > +static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) > +{ > + union hv_hypercall_input control = {0}; > + > + control.code = code; > + control.fast = 1; > +#ifdef CONFIG_X86_64 > + { > + u64 hv_status; > + > + __asm__ __volatile__("call *%3" > + : "=a" (hv_status), > + "+c" (control.as_uint64), "+d" (input1) > + : "m" (hv_hypercall_pg) > + : "cc", "r8", "r9", "r10", "r11"); > + return hv_status; > + } > +#else > + { > + u32 hv_status_hi, hv_status_lo; > + u32 input1_hi = (u32)(input1 >> 32); > + u32 input1_lo = (u32)input1; > + > + __asm__ __volatile__ ("call *%6" > + : "=d"(hv_status_hi), > + "=a"(hv_status_lo), > + "+c"(input1_lo) > + : "d" (control.as_uint32_hi), > + "a" (control.as_uint32_lo), > + "b" (input1_hi), > + "m" (hv_hypercall_pg) > + : "cc", "edi", "esi"); > + > + return hv_status_lo | ((u64)hv_status_hi << 32); > + } > +#endif This is going to need an explicit "sp" annotation to force a stack frame, I think. Otherwise objtool is likely to get mad in a frame-pointer-omitted build.