From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [RFC PATCH 0/5] Load BIOS via toolstack instead of been embedded in hvmloader. Date: Wed, 16 Sep 2015 19:56:44 +0100 Message-ID: <55F9BB6C.4020404@citrix.com> References: <1442423987-14956-1-git-send-email-anthony.perard@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1442423987-14956-1-git-send-email-anthony.perard@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Anthony PERARD , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 16/09/2015 18:19, Anthony PERARD wrote: > Hi all, > > I've start to look at loading the BIOS and the ACPI tables via the > toolstack instead of having them embedded in the hvmloader binary. This is > done by using the same mechanics as the one used to load extra ACPI tables > or SMBIOS. > > - libxl load the blob into it's memory and add it to > struct xc_hvm_build_args.bios_module > - libxc load the blob into the guest memory and give back the guest address > of the blob. > - libxl store the location of the blob (and it's lenght) into xenstore, in > /local/domain/$domid/hvmloader/$blob_name/{address,length} ($blob_name > would be "bios" or "acpi_table"; there is already "acpi" and "smbios" > that exist) > - hvmloader read the addresses from xenstore and put the blob at the right > place. > > How this is looking? > > Right now, this patch series would only work for SeaBIOS. I highly recommend that you build on top of Rogers DMlite series, which already offers a multiboot-style way of adding extra modules to HVM guests. (That was the way I was planning to do this in some copious free time). In particular, storing the address/length in xenstore is conceptually incorrect as the information turns stale as soon as hvmloader starts running. * Modify hvmloader to have a DMLite entry, which gives it a command line and module list * Modify libxc to be able to take an arbitrary quantity of modules, rather than the currently limit of 1 Once the above work times are in place, the actual splitting-up of hvmloader can occur. I recommend a command line way of telling hvmloader which module is what, such as a legacy bios image, (other firmware image?), supplemental acpi table, supplemental smbios table, nvram blob? (This last one will require a bit of extra work so the toolstack can pull the blob back out of the guest on destruction) ~Andrew