Commit cfd8951e authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
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xen: don't map missing memory 



When setting up a pte for a missing pfn (no matching mfn), just create
an empty pte rather than a junk mapping.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
parent 33a84750

arch/x86/include/asm/xen/page.h

+8 −1
Original line number Diff line number Diff line
@@ -41,10 +41,17 @@ extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn); 


static inline unsigned long pfn_to_mfn(unsigned long pfn)

{

	unsigned long mfn;



	if (xen_feature(XENFEAT_auto_translated_physmap))

		return pfn;



	return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;

	mfn = get_phys_to_machine(pfn);



	if (mfn != INVALID_P2M_ENTRY)

		mfn &= ~FOREIGN_FRAME_BIT;



	return mfn;

}



static inline int phys_to_machine_mapping_valid(unsigned long pfn)

arch/x86/xen/mmu.c

+14 −1
Original line number Diff line number Diff line
@@ -745,7 +745,20 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) 
	if (val & _PAGE_PRESENT) {

		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;

		pteval_t flags = val & PTE_FLAGS_MASK;

		val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;

		unsigned long mfn = pfn_to_mfn(pfn);



		/*

		 * If there's no mfn for the pfn, then just create an

		 * empty non-present pte.  Unfortunately this loses

		 * information about the original pfn, so

		 * pte_mfn_to_pfn is asymmetric.

		 */

		if (unlikely(mfn == INVALID_P2M_ENTRY)) {

			mfn = 0;

			flags = 0;

		}



		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;

	}



	return val;