On 12/4/2017 8:57 AM, Kirill A. Shutemov wrote:
On Mon, Dec 04, 2017 at 08:19:11AM -0600, Tom Lendacky wrote:
On 12/4/2017 5:23 AM, Kirill A. Shutemov wrote:
sme_populate_pgd() open-codes a lot of things that are not needed to be
open-coded.
Let's rewrite it in a more stream-lined way.
This would also buy us boot-time switching between support between
paging modes, when rest of the pieces will be upstream.
Hi Kirill,
Unfortunately, some of these can't be changed. The use of p4d_offset(),
pud_offset(), etc., use non-identity mapped virtual addresses which cause
failures at this point of the boot process.
Wat? Virtual address is virtual address. p?d_offset() doesn't care about
what mapping you're using.
Yes it does. For example, pmd_offset() issues a pud_page_addr() call,
which does a __va() returning a non-identity mapped address (0xffff88...).
Only identity mapped virtual addresses have been setup at this point, so
the use of that virtual address panics the kernel.
Thanks,
Tom
Also, calls such as __p4d(), __pud(), etc., are part of the paravirt
support and can't be used yet, either.
Yeah, I missed this. native_make_p?d() has to be used instead.
I can take a closer look at some of the others (p*d_none() and
p*d_large()) which make use of the native_ macros, but my worry would be
that these get changed in the future to the non-native calls and then
boot failures occur.
If you want to avoid paravirt altogher for whole compilation unit, one
more option would be to put #undef CONFIG_PARAVIRT before all includes.
That's hack, but it works. We already use this in arch/x86/boot/compressed
code.
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