From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.20]) (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 775D929423 for ; Fri, 17 Nov 2023 19:23:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Wcl/zIVY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1700249031; x=1731785031; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Bn+u+P5GODO6qvJWbb/a1VxD8akP6RMrDigcWx4W55Y=; b=Wcl/zIVYB0fBqhTE00OHbVxWc7+vDN7/4yfQ0zImqFKUZe0ItEEGj/ns 4utii6BUT8RTeOJMKrk8uzDligmG3YTd2dXA52asXmljEps75Umn78gor okUlibdt99nzeKkx5GBR38c/72Ifqij33R80dQEKA9cuTIylgKMW7U1VT 9yDt256+lYCW94qk+9jQSSiIkLumlfLTirABaxxomJcDE/CgePSIa5sKI xZPkNVI1ooSI9VvdDkcBTQvDekpmc8asJAAFCpbxn5vKjeAuu/1TQWUNq 2US5kbgESwcLze3jHooI0fCIHLT/1TbRaL403J+gPaZTKLMGONltBWr3f Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10897"; a="381744235" X-IronPort-AV: E=Sophos;i="6.04,206,1695711600"; d="scan'208";a="381744235" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2023 11:23:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10897"; a="800579600" X-IronPort-AV: E=Sophos;i="6.04,206,1695711600"; d="scan'208";a="800579600" Received: from phelpsmi-mobl2.amr.corp.intel.com (HELO [10.212.139.180]) ([10.212.139.180]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2023 11:23:50 -0800 Message-ID: Date: Fri, 17 Nov 2023 11:23:47 -0800 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 RESEND] x86/asm: Force native_apic_mem_read to use mov Content-Language: en-US To: Sidharth Telang , marcorr@google.com Cc: acdunlap@google.com, ak@linux.intel.com, alpergun@google.com, ben-linux@fluff.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, jacobhxu@google.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, mingo@redhat.com, nathan@kernel.org, ndesaulniers@google.com, pgonda@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com, tglx@linutronix.de, thomas.lendacky@amd.com, trix@redhat.com, x86@kernel.org References: <20231117181458.2260258-1-sidtelang@google.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/17/23 10:14, Sidharth Telang wrote: >> Is this blocked on an item? There seems to be consensus that this >> patch fixes a bug and is taking the right high-level approach (i.e., >> change the guest code to avoid triggering a sequence that isn't >> supported under CVM exception-based emulation). Without something like >> this, we weren't able to build the kernel w/ CLANG when it is >> configured to run under SEV-ES. > >> We sent out two versions of the patch. One that does the mov directly >> [1] and a second that calls readl [2]. Is one of these two patches >> acceptable? Or do we need to follow up on something? >> >> [1] https://lore.kernel.org/lkml/0D6A1E49-F21B-42AA-BBBF-13BFC308BB1E@zytor.com/T/ >> [2] https://lore.kernel.org/all/20220812183501.3555820-1-acdunlap@google.com/ > > Signal-boosting this thread: is this blocked on any item? Yes, it's blocked on you sending a well-described patch. You sent out two patches which both received a lot of discussion and induced a lot of confusion. Can you please take all the knowledge from this thread and send a third patch that has a proper changelog incorporating all that knowledge? Which approach should that patch have? Whatever one is as close to what native_apic_mem_write() does as possible.