From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 041DFC433B4 for ; Fri, 7 May 2021 21:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC6F260FE6 for ; Fri, 7 May 2021 21:46:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229713AbhEGVrp (ORCPT ); Fri, 7 May 2021 17:47:45 -0400 Received: from mga12.intel.com ([192.55.52.136]:12356 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbhEGVrp (ORCPT ); Fri, 7 May 2021 17:47:45 -0400 IronPort-SDR: TirPp7fMImxyVBNQPLySX7/S1p4Gs4weWVEpxdk+rdJiVwxakLuR2ktZVAljTvJwQP7FiqV5AU KUBZLPHM0MOQ== X-IronPort-AV: E=McAfee;i="6200,9189,9977"; a="178382805" X-IronPort-AV: E=Sophos;i="5.82,282,1613462400"; d="scan'208";a="178382805" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2021 14:46:44 -0700 IronPort-SDR: TsPHdmpeaje8A1mMeStcCLoEz/3fxdWh4p7Ouw62oeA3rCUFn7fhEWLH6qBCaFvaGcyx4h60FF wLTQ8pUkLGeQ== X-IronPort-AV: E=Sophos;i="5.82,282,1613462400"; d="scan'208";a="431677987" Received: from msandrid-mobl.amr.corp.intel.com (HELO [10.212.134.124]) ([10.212.134.124]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2021 14:46:43 -0700 Subject: Re: [RFC v2 10/32] x86/tdx: Wire up KVM hypercalls To: Kuppuswamy Sathyanarayanan , Peter Zijlstra , Andy Lutomirski , Dan Williams , Tony Luck Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org, Isaku Yamahata References: <04de6cd6549eee0b77fe3b0937c4b4b7f0e3ff2e.1619458733.git.sathyanarayanan.kuppuswamy@linux.intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: Date: Fri, 7 May 2021 14:46:41 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <04de6cd6549eee0b77fe3b0937c4b4b7f0e3ff2e.1619458733.git.sathyanarayanan.kuppuswamy@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/26/21 11:01 AM, Kuppuswamy Sathyanarayanan wrote: > From: "Kirill A. Shutemov" > > KVM hypercalls have to be wrapped into vendor-specific TDVMCALLs. How about: KVM hypercalls use the "vmcall" or "vmmcall" instructions. Although the ABI is similar, those instructions no longer function for TDX guests. Make TDVMCALLs instead of VMCALL/VMCALL. > diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h > index 338119852512..2fa85481520b 100644 > --- a/arch/x86/include/asm/kvm_para.h > +++ b/arch/x86/include/asm/kvm_para.h > @@ -6,6 +6,7 @@ > #include > #include > #include > +#include > > extern void kvmclock_init(void); > > @@ -34,6 +35,10 @@ static inline bool kvm_check_and_clear_guest_paused(void) > static inline long kvm_hypercall0(unsigned int nr) > { > long ret; > + > + if (is_tdx_guest()) > + return tdx_kvm_hypercall0(nr); ... all of these look OK. > #endif /* _ASM_X86_TDX_H */ > diff --git a/arch/x86/kernel/tdcall.S b/arch/x86/kernel/tdcall.S > index 81af70c2acbd..964bfd7fc682 100644 > --- a/arch/x86/kernel/tdcall.S > +++ b/arch/x86/kernel/tdcall.S > @@ -11,6 +11,7 @@ > * refer to TDX GHCI specification). > */ > #define TDVMCALL_EXPOSE_REGS_MASK 0xfc00 > +#define TDVMCALL_VENDOR_KVM 0x4d564b2e584454 /* "TDX.KVM" */ > > /* > * TDX guests use the TDCALL instruction to make > @@ -198,3 +199,9 @@ SYM_FUNC_START(__tdvmcall) > call do_tdvmcall > retq > SYM_FUNC_END(__tdvmcall) > + > +SYM_FUNC_START(__tdvmcall_vendor_kvm) > + movq $TDVMCALL_VENDOR_KVM, %r10 > + call do_tdvmcall > + retq > +SYM_FUNC_END(__tdvmcall_vendor_kvm) Granted, this is not a ton of assembly. But, it does look a bit weird. It needs a comment and/or a mention in the changelog. R10 is not part of the function call ABI, but it is a part of the TDVMCALL ABI. This little assembly wrapper lets us reuse do_tdvmcall() for both KVM-specific hypercalls TDVMCALL_VENDOR_KVM and the more generic __tdvmcalls. > --- a/arch/x86/kernel/tdx.c > +++ b/arch/x86/kernel/tdx.c > @@ -8,6 +8,10 @@ > > #include > > +#ifdef CONFIG_KVM_GUEST > +#include "tdx-kvm.c" > +#endif > + > static struct { > unsigned int gpa_width; > unsigned long attributes; I know KVM does weird stuff. But, this is *really* weird. Why are we #including a .c file into another .c file?