From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mx.groups.io with SMTP id smtpd.web12.7159.1606983075107512682 for ; Thu, 03 Dec 2020 00:11:15 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=LXXQ9GJ4; spf=pass (domain: redhat.com, ip: 216.205.24.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606983074; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GyacWP0LFhAAmbPgpo79Offik2qQ6r62MaFXYXqDVak=; b=LXXQ9GJ4PrcMpLYEvp8vhLC6m0EFtuaM+RWg0JIfp7EvzY6Ojw9VcZqni0viBpsqfXDv9G 0qf33imarxmiDA3Oha4xFTUE+yp01kaXtaOXm8jsKpbg2wopkUE518wddGDmpnCy040YHH EsyJmqNMAb9u61UJL0sOvJ4lDqhL/vU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-581-7F7rNjX0OFat0VLNpWFS1A-1; Thu, 03 Dec 2020 03:11:07 -0500 X-MC-Unique: 7F7rNjX0OFat0VLNpWFS1A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CC2CF9A22F; Thu, 3 Dec 2020 08:11:04 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-113-182.ams2.redhat.com [10.36.113.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id A14C25D9CA; Thu, 3 Dec 2020 08:11:00 +0000 (UTC) Subject: Re: [edk2-devel] [PATCH v3 1/6] OvmfPkg/ResetVector: convert SEV-ES Reset Block structure to be GUIDed To: devel@edk2.groups.io, jejb@linux.ibm.com Cc: dovmurik@linux.vnet.ibm.com, Dov.Murik1@il.ibm.com, ashish.kalra@amd.com, brijesh.singh@amd.com, tobin@ibm.com, david.kaplan@amd.com, jon.grimm@amd.com, thomas.lendacky@amd.com, frankeh@us.ibm.com, "Dr . David Alan Gilbert" , Jordan Justen , Ard Biesheuvel References: <20201130202819.3910-1-jejb@linux.ibm.com> <20201130202819.3910-2-jejb@linux.ibm.com> From: "Laszlo Ersek" Message-ID: <8d3592ef-9e18-224c-fae0-fe6604e74b5e@redhat.com> Date: Thu, 3 Dec 2020 09:10:59 +0100 MIME-Version: 1.0 In-Reply-To: <20201130202819.3910-2-jejb@linux.ibm.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 11/30/20 21:28, James Bottomley wrote: > Convert the current ES reset block structure to an extensible guid > based structure by appending a header and length, which allow for > multiple guid based data packets to be inserted. > > Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3077 > Signed-off-by: James Bottomley > > --- > > v2: added > v3: reworked > --- > OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 51 +++++++++++++++----- > 1 file changed, 40 insertions(+), 11 deletions(-) Reviewed-by: Laszlo Ersek Thank you! Laszlo > diff --git a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm > index 980e0138e7fe..9e0a74fddfc1 100644 > --- a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm > +++ b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm > @@ -25,21 +25,40 @@ ALIGN 16 > TIMES (0x1000 - ($ - EndOfPageTables) - 0x20) DB 0 > %endif > > +; > +; Padding to ensure first guid starts at 0xffffffd0 > +; > +TIMES (15 - ((guidedStructureEnd - guidedStructureStart + 15) % 16)) DB 0 > + > +; GUIDed structure. To traverse this you should first verify the > +; presence of the table footer guid > +; (96b582de-1fb2-45f7-baea-a366c55a082d) at 0xffffffd0. If that > +; is found, the two bytes at 0xffffffce are the entire table length. > +; > +; The table is composed of structures with the form: > +; > +; Data (arbitrary bytes identified by guid) > +; length from start of data to end of guid (2 bytes) > +; guid (16 bytes) > +; > +; so work back from the footer using the length to traverse until you > +; either find the guid you're looking for or run off the beginning of > +; the table. > +; > +guidedStructureStart: > + > ; > ; SEV-ES Processor Reset support > ; > ; sevEsResetBlock: > ; For the initial boot of an AP under SEV-ES, the "reset" RIP must be > -; programmed to the RAM area defined by SEV_ES_AP_RESET_IP. A known offset > -; and GUID will be used to locate this block in the firmware and extract > -; the build time RIP value. The GUID must always be 48 bytes from the > -; end of the firmware. > +; programmed to the RAM area defined by SEV_ES_AP_RESET_IP. The data > +; format is: > ; > -; 0xffffffca (-0x36) - IP value > -; 0xffffffcc (-0x34) - CS segment base [31:16] > -; 0xffffffce (-0x32) - Size of the SEV-ES reset block > -; 0xffffffd0 (-0x30) - SEV-ES reset block GUID > -; (00f771de-1a7e-4fcb-890e-68c77e2fb44e) > +; IP value [0:15] > +; CS segment base [31:16] > +; > +; GUID (SEV-ES reset block): 00f771de-1a7e-4fcb-890e-68c77e2fb44e > ; > ; A hypervisor reads the CS segement base and IP value. The CS segment base > ; value represents the high order 16-bits of the CS segment base, so the > @@ -48,8 +67,6 @@ ALIGN 16 > ; program the EIP register with the IP value as read. > ; > > -TIMES (32 - (sevEsResetBlockEnd - sevEsResetBlockStart)) DB 0 > - > sevEsResetBlockStart: > DD SEV_ES_AP_RESET_IP > DW sevEsResetBlockEnd - sevEsResetBlockStart > @@ -57,6 +74,18 @@ sevEsResetBlockStart: > DB 0x89, 0x0E, 0x68, 0xC7, 0x7E, 0x2F, 0xB4, 0x4E > sevEsResetBlockEnd: > > +; > +; Table footer: > +; > +; length of whole table (16 bit word) > +; GUID (table footer): 96b582de-1fb2-45f7-baea-a366c55a082d > +; > + DW guidedStructureEnd - guidedStructureStart > + DB 0xDE, 0x82, 0xB5, 0x96, 0xB2, 0x1F, 0xF7, 0x45 > + DB 0xBA, 0xEA, 0xA3, 0x66, 0xC5, 0x5A, 0x08, 0x2D > + > +guidedStructureEnd: > + > ALIGN 16 > > applicationProcessorEntryPoint: >