Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 3 Apr 2019 23:27:00 -0700 (PDT)
From:      "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net>
To:        Rebecca Cran <rebecca@bluestop.org>
Cc:        freebsd-virtualization@freebsd.org
Subject:   Re: Bhyve with UEFI edk2-stable201903 and CSM support - debugging the crash
Message-ID:  <201904040627.x346R09b031282@gndrsh.dnsmgr.net>
In-Reply-To: <9927beac-92cd-1059-298d-b7ffd9f34a42@bluestop.org>

next in thread | previous in thread | raw e-mail | index | archive | help
> I've spent some time trying to figure out where and why the UEFI 2.70 
> firmware is crashing when built with CSM support under Bhyve.
> 
> The first thing I noticed is that the code that builds the E820 table 
> doesn't appear to be finding the location of the EBDA at 0x40E: the 
> first entry should be something like 0x0 to 0x4cf00, but is 0-0 instead.

Since your building a bios there should be a table some
place in some header or c file that builds the EBDA and
puts a pointer to it at 0x40E.  This should be someplace
in the CSM legacy support stuff since the EBSA is a legacy
bios thingy.

You may want to look at the prior port of UEFI/CSM and see
how this was done in that code, it may be a hard coded hack.

> E820[ 0]: 0x?????????????? 0 ---- 0x?????????????? 0, Type = 0x1
> E820[ 1]: 0x?????????????? 0 ---- 0x?????????? A0000, Type = 0x2
> E820[ 2]: 0x?????????? E0000 ---- 0x????????? 100000, Type = 0x2
> E820[ 3]: 0x????????? 100000 ---- 0x????????? 406000, Type = 0x1
> 
> ...
> 
> 
> As an aside, I'm working on a patch to submit upstream to fix the output 
> so it pads with zeros instead of spaces.
> 
> 
> I've also found that as was probably pretty obvious the system is 
> crashing when trying to call into the CSM to initialize it. It gets as 
> far as calling AsmThunk16 (AsmThunk.nasm), but never appears to reach 
> CsmMain in BhyveCsm16.c. I'll see if I can work on it some more to 
> narrow down the error.

Well I would think if the legacy memory region table is bogus
that would be a good start point to fix.

> 
> Another thing: the GNUmakefile in OvmfPkg/Csm/BhyveCsm16 has "CC ?= 
> gcc", but it appears the build system already sets CC to "cc", which 
> uses the system's clang compiler, which can't compile the assembly code.
> 
> I don't know if we might want to either hard-code CC to "gcc" for now, 
> or have users create a 'cc' symlinks in BaseTools/Bin/FreeBSD-amd64 ?

I would firmcode it, if CC=cc then CC=gcc, this would allow a person
to override CC with something else and still have all the other stuff
work out, except for this specific point that does infact need gcc.

> Rebecca Cran
-- 
Rod Grimes                                                 rgrimes@freebsd.org



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201904040627.x346R09b031282>