Re: [Xen-devel] Is there any limitation on the firmware size in Xen?

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, May 10, 2017 at 08:29:35AM -0600, Charles Arnold wrote:
> I was asked the following question which I am posting to the list.
> 
> "
> My name is Gary Lin, and I am the maintainer of the OVMF package, a UEFI
> implementation for the virtual machines.
> 
> Recently, I was testing an upstream patchset[*] and encountered some
> problems in Xen. Maybe you can help me or give me some hints.
> 
> To be short, the edk2/ovmf upstream is going to increase the firmware
> size from 2MB to 4MB to fulfill windows HCK, and we have to test
> different types of VM to make sure the patchset really work. When I was
> using the 2MB build, my Xen HVM worked as expected and showed the boot
> menu. However, if I use the 4MB build, I got something like this from
> "xl dmesg":
> 
> (d32)  - CPU0 ... 39-bit phys ... fixed MTRRs ... var MTRRs [1/8] ... done.
> (d32) Testing HVM environment:
> (d32)  - REP INSB across page boundaries ... passed
> (d32)  - GS base MSRs and SWAPGS ... passed
> (d32) Passed 2 of 2 tests
> (d32) Writing SMBIOS tables ...
> (d32) Loading OVMF ...
> (d32) no BIOS ROM image found
> (d32) *** HVMLoader bug at hvmloader.c:389
> (d32) *** HVMLoader crashed.
> 
> I tried to trace the code and found that in libxl__load_hvm_firmware_module()
> in tools/libxl/libxl_dom.c actully loaded the file and add_module_to_list()
> in tools/libxc/xc_dom_x86.c was loading a firmware "module" with 4194304
> bytes. However, when hvmloader loaded "bios_module" with get_module_entry(),
> modlist is NULL. It seems the firmware data was removed for some reason.
> 
> Here are my questions:
> 
> 1. Is there any limitation on the firmware size in Xen?
> 

OVMF is loaded into 4GB - ovmf_size. There shouldn't be limitation in
that regard. HVMloader should be happy with that address range.

Like Jan suggested, it would be worth investigating if it is corrupted
by something else.


Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel