From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48066) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqLNB-0007RW-9p for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:39:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dqLN6-0003fx-E8 for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:39:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50358) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dqLN6-0003fT-6z for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:39:08 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 01CC2C049D7F for ; Fri, 8 Sep 2017 15:39:07 +0000 (UTC) Date: Fri, 8 Sep 2017 18:39:01 +0300 From: "Michael S. Tsirkin" Message-ID: <20170908183337-mutt-send-email-mst@kernel.org> References: <20170807181618.22562-1-marcandre.lureau@redhat.com> <20170807181618.22562-4-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20170807181618.22562-4-marcandre.lureau@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v5 3/8] fw_cfg: add vmcoreinfo file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Cc: qemu-devel@nongnu.org, imammedo@redhat.com, berrange@redhat.com, ehabkost@redhat.com, anderson@redhat.com, lersek@redhat.com On Mon, Aug 07, 2017 at 08:16:13PM +0200, Marc-Andr=E9 Lureau wrote: > diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt > index 08c00bdf44..37d0f9f40a 100644 > --- a/docs/specs/fw_cfg.txt > +++ b/docs/specs/fw_cfg.txt > @@ -136,6 +136,22 @@ struct FWCfgFile { /* an individual file entry, 6= 4 bytes total */ > char name[56]; /* fw_cfg item name, NUL-terminated ascii */ > }; > =20 > +=3D=3D=3D etc/vmcoreinfo =3D=3D=3D > + > +A guest may use this entry to add information details to qemu > +dumps. The entry gives location and size of an ELF note that is > +appended in qemu dumps. > + > +The entry is of 12 bytes with this format: > + > +struct FWCfgVMCoreInfo { > + uint64_t paddr; /* physical address of ELF note, LE */ > + uint32_t size; /* size of ELF note region, LE */ > +}; > + > +The note format/class must be of the target bitness and the size must > +be less than 1Mb. > + I would say adding a format bitmap would make sense for future compatibil= ity. How about: struct FWCfgVMCoreInfo { uint16_t host_format; /* Formats host supports. 0x1 LE - ELF no= te. Other bits - ignored. */ uint16_t guest_format; /* Formats guest supplies. Must be 0x1 LE= */ uint32_t size; /* size of ELF note region, LE */ uint64_t paddr; /* physical address of ELF note, LE */ }; > =3D=3D=3D All Other Data Items =3D=3D=3D > =20 > Please consult the QEMU source for the most up-to-date and authoritati= ve list > --=20 > 2.14.0.1.geff633fa0