Hi
Am 03.06.25 um 03:49 schrieb Michael Kelley:
[...]
Will the VMA have VM_PFNMAP or VM_MIXEDMAP set? PFN_SPECIAL is a
horrible hack.
In another thread, you mention that you use PFN_SPECIAL to bypass the
check in vm_mixed_ok(), so VM_MIXEDMAP is likely not set?
The VMA has VM_PFNMAP set, not VM_MIXEDMAP. It seemed like
VM_MIXEDMAP is somewhat of a superset of VM_PFNMAP, but maybe that's
a wrong impression. vm_mixed_ok() does a thorough job of validating the
use of __vm_insert_mixed(), and since what I did was allowed, I thought
perhaps it was OK. Your feedback has set me straight, and that's what I
needed. :-)
But the whole approach is moot with Alistair Popple's patch set that
eliminates pfn_t. Is there an existing mm API that will do mkwrite on a
special PTE in a VM_PFNMAP VMA? I didn't see one, but maybe I missed
it. If there's not one, I'll take a crack at adding it in the next version of my
patch set.
What is the motivation behind this work? The driver or fbdev as a whole
does not have much of a future anyway.
I'd like to suggest removing hyperv_fb entirely in favor of hypervdrm?
Best regards
Thomas
Michael
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Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
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