Re: input/output error _at_boot

On Thu, 9 Mar 2017 06:00:23 +0000 Dexuan Cui <decui_at_microsoft.com> wrote

> Hi Roberto, 
> Thanks for sending me your memmap and this is a temporary workaround
> patch for you:
> https://github.com/dcui/freebsd/commit/0edd1db55fbbb56352d6024250e4ae7dd8ad31
> e3.patch 
>
> I put the memmap info here for people who're interested:
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=211746#c26
> 
> We can notice there is a 4MB BootServicesCode range at [12MB, 16MB) .
> loader.efi just writes into this range by force -- this is unsafe anyway!
> 
> To fix this correctly & thoroughly, IMO we need a relocatable kernel, but
> that would require a lot of complicated long term work:
> https://reviews.freebsd.org/D9686?id=25414#inline-56969
> 
> For now, I suggest we should only apply the idea "reduce the size of the
> staging area if necessary" to VM running on Hyper-V, we should restore the
> old behavior on physical machines since that has been working for people
> for a long period of time, though it's  potentially unsafe.
> 
> I think in the loader we can use CPUID to tell if we're running on Hyper-V or
> not. 

Indeed that will provide *capability*. But I'm don't think that can
tell you that it is currently *enabled* || *in use*.
The CPU I experienced the (u)efi issue on has the capability,
but I've turned it off, as it's more hindrance for performance,
for the server' intended use.

IOW I think just probing for *capability* isn't going to be enough.

--Chris
>
> Thanks,
> -- Dexuan
> 
> > -----Original Message-----
> > From: owner-freebsd-current_at_freebsd.org [mailto:owner-freebsd-
> > current_at_freebsd.org] On Behalf Of Dexuan Cui
> > Sent: Thursday, March 9, 2017 10:44
> > To: Roberto Rodriguez Jr <rob.rodz.jr9_at_gmail.com>
> > Cc: FreeBSD Current <freebsd-current_at_freebsd.org>
> > Subject: RE: input/output error _at_boot
> > 
> > Hmm, Alex did report 314891 worked.
> > 
> > Can you please post the full boot log of the loader?
> > Especially, when you see the “OK” prompt, can you please run the
“memmap”
> > command like this link ...
> > 
> > You can take a photo of the screen and send it to me, if it’s too big.
> > 
> > Thanks,
> > -- Dexuan
>