Commit 9a58b352 authored by Jan Beulich's avatar Jan Beulich Committed by Boris Ostrovsky
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xen/x86: restrict PV Dom0 identity mapping 



When moving away RAM pages, there having been a mapping of those is not
a proper indication that instead MMIO should be mapped there. At the
point in time this effectively covers the low megabyte only. Mapping of
that is, however, the job of init_mem_mapping(). Comparing the two one
can also spot that we've been wrongly (or at least inconsistently) using
PAGE_KERNEL_IO here.

Simply zap any such mappings instead.

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/038b8c02-3621-d66a-63ae-982ccf67ae88@suse.com


Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 344485a2

arch/x86/xen/setup.c

+3 −3
Original line number Diff line number Diff line
@@ -425,13 +425,13 @@ static unsigned long __init xen_set_identity_and_remap_chunk( 
	}



	/*

	 * If the PFNs are currently mapped, the VA mapping also needs

	 * to be updated to be 1:1.

	 * If the PFNs are currently mapped, their VA mappings need to be

	 * zapped.

	 */

	for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)

		(void)HYPERVISOR_update_va_mapping(

			(unsigned long)__va(pfn << PAGE_SHIFT),

			mfn_pte(pfn, PAGE_KERNEL_IO), 0);

			native_make_pte(0), 0);



	return remap_pfn;

}