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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AAF53C5478C for ; Tue, 27 Feb 2024 15:43:29 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rezbb-0002mR-4y; Tue, 27 Feb 2024 10:42:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rezbZ-0002m5-SF for qemu-devel@nongnu.org; Tue, 27 Feb 2024 10:42:53 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rezbU-00079S-5N for qemu-devel@nongnu.org; Tue, 27 Feb 2024 10:42:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709048566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=9F5yUOES5ELNg7LCNTzZy1CeXKfGhzhmrWj1sbHY2YE=; b=Bc8vz+ZuwN4lQK0kbB/ZMgGzqc/bLINw0QPRUAFhKYgIpsaBCqJ91+xo7SOSmKJ88XLNnE zgbgp3cSKXtplCzDgsDbde6C5jd0UJfTimvXoJk9JP4kkj19Yp7qIWYNNvY8tcOZ7HOdrw 7g7H/Ldvw4XdV1dDDG+Hs8Gad1NSiEk= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-52-YWvDMh15MFysBMssrCrO0g-1; Tue, 27 Feb 2024 10:42:42 -0500 X-MC-Unique: YWvDMh15MFysBMssrCrO0g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C87D03C0275E; Tue, 27 Feb 2024 15:42:41 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8165E2166B33; Tue, 27 Feb 2024 15:42:41 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6E16121E6740; Tue, 27 Feb 2024 16:42:40 +0100 (CET) From: Markus Armbruster To: Xiaoyao Li Cc: Paolo Bonzini , David Hildenbrand , Igor Mammedov , "Michael S . Tsirkin" , Marcel Apfelbaum , Richard Henderson , Peter Xu , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Cornelia Huck , Daniel =?utf-8?Q?P=2EBerrang=C3=A9?= , Eric Blake , Marcelo Tosatti , qemu-devel@nongnu.org, kvm@vger.kernel.org, Michael Roth , Sean Christopherson , Claudio Fontana , Gerd Hoffmann , Isaku Yamahata , Chenyi Qiang Subject: Re: [PATCH v4 53/66] i386/tdx: Wire TDX_REPORT_FATAL_ERROR with GuestPanic facility In-Reply-To: <7ef9d3c0-2bab-4edc-a5dc-156d17a467ed@intel.com> (Xiaoyao Li's message of "Tue, 27 Feb 2024 22:51:59 +0800") References: <20240125032328.2522472-1-xiaoyao.li@intel.com> <20240125032328.2522472-54-xiaoyao.li@intel.com> <87v86kehts.fsf@pond.sub.org> <1d7f7c1b-cfaa-4de6-80a0-8d1104440f54@intel.com> <87le76dt1g.fsf@pond.sub.org> <09c5fd9b-be96-45b6-b48e-772d5b5aad16@intel.com> <87wmqqawa2.fsf@pond.sub.org> <7ef9d3c0-2bab-4edc-a5dc-156d17a467ed@intel.com> Date: Tue, 27 Feb 2024 16:42:40 +0100 Message-ID: <87o7c1ap73.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.088, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Xiaoyao Li writes: > On 2/27/2024 9:09 PM, Markus Armbruster wrote: > [...] >>>>>>> @@ -566,6 +569,27 @@ >>>>>>> 'psw-addr': 'uint64', >>>>>>> 'reason': 'S390CrashReason'}} >>>>>>> >>>>>>> +## >>>>>>> +# @GuestPanicInformationTdx: >>>>>>> +# >>>>>>> +# TDX Guest panic information specific to TDX GCHI >>>>>>> +# TDG.VP.VMCALL. >>>>>>> +# >>>>>>> +# @error-code: TD-specific error code >>>>>> >>>>>> Where could a user find information on these error codes? >>>>> >>>>> TDX GHCI (Guset-host-communication-Interface)spec. It defines all the >>>>> TDVMCALL leaves. >>>>> >>>>> 0: panic; >>>>> 0x1 - 0xffffffff: reserved. >>>> >>>> Would it make sense to add a reference? >>> >>> https://cdrdv2.intel.com/v1/dl/getContent/726792 >> >> URLs have this annoying tendency to rot. >> >> What about >> >> # @error-code: Error code as defined in "Guest-Hypervisor Communication >> # Interface (GHCI) Specification for Intel TDX 1.5" > > I think it gets mentioned at the beginning of @GuestPanicInformationTdx > > TDX Guest panic information specific to TDX GHCI > TDG.VP.VMCALL. > > Do we still to mention it in every single member? No, I didn't recognize the alphabet soup there as a reference :) Let me try again: ## # @GuestPanicInformationTdx: # # TDX Guest panic information specific to TDX, as specified in the # "Guest-Hypervisor Communication Interface (GHCI) Specification", # section TDG.VP.VMCALL. # # @error-code: TD-specific error code # [...] # # Since: 9.0 ## >>>>>>> +# >>>>>>> +# @gpa: guest-physical address of a page that contains additional >>>>>>> +# error data, in forms of zero-terminated string. >>>>>> >>>>>> "in the form of a zero-terminated string" >>>>> >>>>> fixed. >>>>> >>>>>>> +# >>>>>>> +# @message: Human-readable error message provided by the guest. Not >>>>>>> +# to be trusted. >>>>>> >>>>>> How is this message related to the one pointed to by @gpa? >>>>> >>>>> In general, @message contains a brief message of the error. While @gpa >>>>> (when valid) contains a verbose message. >>>>> >>>>> The reason why we need both is because sometime when TD guest hits a >>>>> fatal error, its memory may get corrupted so we cannot pass information >>>>> via @gpa. Information in @message is passed through GPRs. >>>> >>>> Well, we do pass information via @gpa, always. I guess it page's >>>> contents can be corrupted. >>> >>> No. It's not always. the bit 63 of the error code is "GPA valid" bit. >>> @gpa is valid only when bit 63 of error code is 1. >>> >>> And current Linux TD guest implementation doesn't use @gpa at all. >>> https://github.com/torvalds/linux/blob/45ec2f5f6ed3ec3a79ba1329ad585497cdcbe663/arch/x86/coco/tdx/tdx.c#L131 >> >> Aha! >> >> Why would we want to include @gpa when the "GPA valid" bit is off? >> >> If we do want it, then >> >> # @gpa: guest-physical address of a page that contains more verbose >> # error information, as zero-terminated string. Valid when the >> # "GPA valid" bit is set in @error-code. >> >> If we don't, then make @gpa optional, present when valid, and document >> it like this: >> >> # @gpa: guest-physical address of a page that contains more verbose >> # error information, as zero-terminated string. Present when the >> # "GPA valid" bit is set in @error-code. > > I will go this direction. > > thanks! You're welcome! [...]