x86/xen: set regions above the end of RAM as 1:1 (25b884a8) · Commits · 戴 / test

PCI devices may have BARs located above the end of RAM so mark such frames as identity frames in the p2m (instead of the default of missing). PFNs outside the p2m (above MAX_P2M_PFN) are also considered to be identity frames for the same reason. Signed-off-by:

David Vrabel <david.vrabel@citrix.com> Reviewed-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/p2m.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -507,7 +507,7 @@ unsigned long get_phys_to_machine(unsigned long pfn)
		unsigned topidx, mididx, idx;

		if (unlikely(pfn >= MAX_P2M_PFN))
		return INVALID_P2M_ENTRY;
		return IDENTITY_FRAME(pfn);

		topidx = p2m_top_index(pfn);
		mididx = p2m_mid_index(pfn);

arch/x86/xen/setup.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -468,6 +468,15 @@ char * __init xen_memory_setup(void)
		i++;
		}

		/*
		* Set the rest as identity mapped, in case PCI BARs are
		* located here.
		*
		* PFNs above MAX_P2M_PFN are considered identity mapped as
		* well.
		*/
		set_phys_range_identity(map[i-1].addr / PAGE_SIZE, ~0ul);

		/*
		* In domU, the ISA region is normal, usable memory, but we
		* reserve ISA memory anyway because too many things poke

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