Re: [Xen-devel] [PATCH 2/2] efi/boot: Don't free ebmalloc area at all

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 28.02.17 at 16:20, <andrew.cooper3@xxxxxxxxxx> wrote:
> Freeing part of the BSS back for general use proves to be problematic.  It is
> not accounted for in xen_in_range(), causing errors when constructing the
> IOMMU tables, resulting in a failure to boot.
> 
> Other smaller issues are that tboot treats the entire BSS as hypervisor data,
> creating and checking a MAC of it on S3, and that, by being 1MB in size,
> freeing it guarentees to shatter the hypervisor superpage mappings.
> 
> Judging by the content stored in it, 1MB is overkill on size.  Drop it to a
> more-reasonable 32kB and keep the entire buffer around after boot.

Well, that's just because right now there's only a single user. The
reason I refused Daniel making it smaller than its predecessor is
that we can't really give a good estimate of how much data may
need storing there: The memory map can have hundreds of entries
and command lines for modules may also be almost arbitrarily long.

What I don't recall, Daniel: Why was it that we can't use EFI boot
services allocations here?

Jan


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