Date: Fri, 11 Aug 2017 13:00:31 -0700 From: Mark Johnston <markj@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: "freebsd-arch@freebsd.org" <arch@freebsd.org> Subject: Re: Proposed Enhancements to the EFI booting Message-ID: <20170811200031.GD19972@wkstn-mjohnston.west.isilon.com> In-Reply-To: <CANCZdfpxnUTnXJsJ6rkUjRpWMtr5vcrQoaSXDfq%2BLzZmVwUCYw@mail.gmail.com> References: <CANCZdfohX1J-c5E4BHd=YoPXj3=tx7b_fndqfFA8bv2UiWgubw@mail.gmail.com> <20170811194028.GB19972@wkstn-mjohnston.west.isilon.com> <CANCZdfpxnUTnXJsJ6rkUjRpWMtr5vcrQoaSXDfq%2BLzZmVwUCYw@mail.gmail.com>
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On Fri, Aug 11, 2017 at 01:48:02PM -0600, Warner Losh wrote: > > There is also a "bootme" GPT flag that is currently ignored when booting > > using boot1.efi. We use it to avoid in-place upgrades: there are two > > root filesystems, only one of which is mounted during boot. Upgrades are > > done by installing the to-version of the OS to the inactive root > > filesystem, flipping the "bootme" flag off on the active partition, > > flipping it on on the inactive partition, and rebooting. > > > > Correct. EFI Boot Manager has a concept of profiles being active or not > active. That's how this functionality will be implemented. There's no > standardized notion of a partition being bootable or not. That's a FreeBSD > extension. same with bootnext and bootfail flags. > > So upgrades would become flipping the boot order in UEFI:BootOrder and/or > toggling active on the two UEFI:BootXXXX variables. It just changes the > command you need to issue from gpart <mumble> to efibootmgr <mumble>. > > > > How should this interact with step 4 of your algorithm? Should we prefer > > a GPT "bootme" entry over a filesystem on the same device as boot1.efi? > > > No. We shouldn't. That duplicates functionality, and the flags bits we need > to make these decisions are a pain to get to in boot1.efi. They are FreeBSD > specific, but won't be carried forward since better functionality already > exists in the BootOrder and BootXXX variables. > > This is much more flexible as well, since it allows you to have multiple > profiles that point to the same partition, but have different parameters, > only one of which is active at any time, which is impossible with the old > GPT scheme. Ok, that's fine with me. I just wanted to point out that that functionality is both useful and currently missing, so I'm glad that there will be a replacement with a simple interface.
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