From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757541AbdEVKoI (ORCPT ); Mon, 22 May 2017 06:44:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59124 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757403AbdEVKoG (ORCPT ); Mon, 22 May 2017 06:44:06 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 27D9961D10 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=vkuznets@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 27D9961D10 From: Vitaly Kuznetsov To: Andy Lutomirski Cc: devel@linuxdriverproject.org, Stephen Hemminger , Jork Loeser , Haiyang Zhang , x86@kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH v3 04/10] x86/hyper-v: fast hypercall implementation References: <20170519140953.1167-1-vkuznets@redhat.com> <20170519140953.1167-5-vkuznets@redhat.com> <1fa6d42d-0f2d-2db6-47ad-d1ae06e13f02@kernel.org> Date: Mon, 22 May 2017 12:44:02 +0200 In-Reply-To: <1fa6d42d-0f2d-2db6-47ad-d1ae06e13f02@kernel.org> (Andy Lutomirski's message of "Sat, 20 May 2017 20:18:15 -0700") Message-ID: <87y3tptbm5.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 22 May 2017 10:44:06 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andy Lutomirski writes: > 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. > You mean I should do something like diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 359967f..f86c4ae 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -221,6 +221,7 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output) static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) { union hv_hypercall_input control = {0}; + register void *__sp asm(_ASM_SP); control.code = code; control.fast = 1; @@ -228,8 +229,8 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) { u64 hv_status; - __asm__ __volatile__("call *%3" - : "=a" (hv_status), + __asm__ __volatile__("call *%4" + : "=a" (hv_status), "+r" (__sp), "+c" (control.as_uint64), "+d" (input1) : "m" (hv_hypercall_pg) : "cc", "r8", "r9", "r10", "r11"); @@ -241,10 +242,11 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) u32 input1_hi = (u32)(input1 >> 32); u32 input1_lo = (u32)input1; - __asm__ __volatile__ ("call *%6" + __asm__ __volatile__ ("call *%7" : "=d"(hv_status_hi), "=a"(hv_status_lo), - "+c"(input1_lo) + "+c"(input1_lo), + "+r"(__sp) : "d" (control.as_uint32_hi), "a" (control.as_uint32_lo), "b" (input1_hi), (stollen from 0e8e2238)? hv_do_hypercall() will need this adjustment too, I think. -- Vitaly