On Fri, 24 Apr 2020 at 19:03, Will Deacon <will@xxxxxxxxxx> wrote: > > On Fri, Apr 24, 2020 at 09:40:51AM +0100, Will Deacon wrote: > > On Thu, Apr 23, 2020 at 06:38:39PM +0100, Andre Przywara wrote: > > > an update for the CFI flash emulation, addressing Alex' comments and > > > adding direct mapping support. > > > The actual code changes to the flash emulation are minimal, mostly this > > > is about renaming and cleanups. > > > This versions now adds some patches. 1/5 is a required fix, the last > > > three patches add mapping support as an extension. See below. > > > > Cheers, this mostly looks good to me. I've left a couple of minor comments, > > and I'll give Alexandru a chance to have another look, but hopefully we can > > merge it soon. > > Ok, I pushed this out along with the follow-up patch. > Cheers for that, this is useful stuff. For the record, I did a quick benchmark on RPi4 booting Debian in a VM, and I get the following delays (with GRUB and EFI timeouts both set to 0) 17:04:58.487065 17:04:58.563700 UEFI firmware (version built at 22:13:20 on Apr 23 2020) 17:04:58.853653 Welcome to GRUB! 17:04:58.924606 Booting `Debian GNU/Linux' 17:04:58.927835 Loading Linux 5.5.0-2-arm64 ... 17:04:59.063490 Loading initial ramdisk ... 17:05:01.303560 /dev/vda2: recovering journal 17:05:01.408861 /dev/vda2: clean, 37882/500960 files, 457154/2001920 blocks 17:05:09.646023 Debian GNU/Linux bullseye/sid rpi4vm64 ttyS0 So it takes less than 400 ms from starting kvmtool to entering GRUB when the boot path is set normally. Any other delays you are observing may be due to the fact that no boot path has been configured yet, which is why it attempts PXE boot or other things. Also, note that you can pass the --rng option to kvmtool to get the EFI_RNG_PROTOCOL to be exposed to the EFI stub, for KASLR and for seeding the kernel's RNG.
