[PATCH] x86/kexec: Only write through identity mapping of control page

[Dave Hansen]

On 12/12/24 12:11, David Woodhouse wrote:
> From: David Woodhouse <dwmw at amazon.co.uk>
> 
> The virtual mapping of the control page may have been _PAGE_GLOBAL and
> thus its PTE might not have been flushed on the %cr3 switch and it might
> effectively still be read-only. Move the writes to it down into the
> identity_mapped() function where the same %rip-relative addressing will
> get the new mapping.
> 
> The stack is fine, as that's using the identity mapped address anyway.

Shouldn't we also ensure that Global entries don't bite anyone else?
Something like the completely untested attached patch?
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