Re: [PATCH] ArmPkg: update InvalidateInstructionCacheRange to flush only to PoU

[Mark Rutland <mark.rutland@arm.com>]

On Wed, Jan 23, 2019 at 10:54:56AM +0100, Laszlo Ersek wrote:
> On 01/23/19 10:26, Ard Biesheuvel wrote:
> > On Wed, 23 Jan 2019 at 10:14, Laszlo Ersek <lersek@redhat.com> wrote:
> >> On 01/22/19 16:37, Ard Biesheuvel wrote:
> 
> >>> Is SetUefiImageMemoryAttributes() being
> >>> called to remap the memory R-X ?
> >>
> >> No, it is not; the grub binary in question doesn't have the required
> >> section alignment (... I hope at least that that's what your question
> >> refers to):
> >>
> >>> ProtectUefiImageCommon - 0x3E6C54C0
> >>>   - 0x000000013BEEF000 - 0x0000000000030600
> >>> !!!!!!!!  ProtectUefiImageCommon - Section Alignment(0x200) is
> >> incorrect  !!!!!!!!
> > 
> > This is puzzling, given that the exact same binary works on Mustang.
> 
> And even on the original (unspecified) hardware, the same binary works
> frequently. My understanding is that there are five VMs executing reboot
> loops in parallel, on the same host, and 4 out of 5 may hit the issue in
> a reasonable time period (300 reboots or so).

Interesting.

Do you happen to know how many VMID bits the host has? If it has an 8-bit VMID,
this could be indicative of some problem upon overflow.

Can you point us at the host kernel?

Thanks,
Mark.