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Commit 0aad5689 authored by Juergen Gross's avatar Juergen Gross Committed by David Vrabel
Browse files

xen: Hide get_phys_to_machine() to be able to tune common path 



Today get_phys_to_machine() is always called when the mfn for a pfn
is to be obtained. Add a wrapper __pfn_to_mfn() as inline function
to be able to avoid calling get_phys_to_machine() when possible as
soon as the switch to a linear mapped p2m list has been done.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 792230c3

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

+20 −6
Original line number Diff line number Diff line
@@ -59,6 +59,21 @@ extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
				     struct page **pages, unsigned int count);

extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);



/*

 * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine():

 * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. No indicator

 *   bits (identity or foreign) are set.

 * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set

 *   identity or foreign indicator will be still set. __pfn_to_mfn() is

 *   encapsulating get_phys_to_machine().

 * - get_phys_to_machine() is to be called by __pfn_to_mfn() only to allow

 *   for future optimizations.

 */

static inline unsigned long __pfn_to_mfn(unsigned long pfn)

{

	return get_phys_to_machine(pfn);

}



static inline unsigned long pfn_to_mfn(unsigned long pfn)

{

	unsigned long mfn;
@@ -66,7 +81,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn) 
	if (xen_feature(XENFEAT_auto_translated_physmap))

		return pfn;



	mfn = get_phys_to_machine(pfn);

	mfn = __pfn_to_mfn(pfn);



	if (mfn != INVALID_P2M_ENTRY)

		mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
@@ -79,7 +94,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn) 
	if (xen_feature(XENFEAT_auto_translated_physmap))

		return 1;



	return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;

	return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY;

}



static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
@@ -113,7 +128,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) 
		return mfn;



	pfn = mfn_to_pfn_no_overrides(mfn);

	if (get_phys_to_machine(pfn) != mfn) {

	if (__pfn_to_mfn(pfn) != mfn) {

		/*

		 * If this appears to be a foreign mfn (because the pfn

		 * doesn't map back to the mfn), then check the local override
@@ -129,8 +144,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) 
	 * entry doesn't map back to the mfn and m2p_override doesn't have a

	 * valid entry for it.

	 */

	if (pfn == ~0 &&

			get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))

	if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))

		pfn = mfn;



	return pfn;
@@ -176,7 +190,7 @@ static inline unsigned long mfn_to_local_pfn(unsigned long mfn) 
		return mfn;



	pfn = mfn_to_pfn(mfn);

	if (get_phys_to_machine(pfn) != mfn)

	if (__pfn_to_mfn(pfn) != mfn)

		return -1; /* force !pfn_valid() */

	return pfn;

}

arch/x86/xen/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -387,7 +387,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) 
		unsigned long mfn;



		if (!xen_feature(XENFEAT_auto_translated_physmap))

			mfn = get_phys_to_machine(pfn);

			mfn = __pfn_to_mfn(pfn);

		else

			mfn = pfn;

		/*

arch/x86/xen/p2m.c

+3 −3
Original line number Diff line number Diff line
@@ -787,7 +787,7 @@ static int m2p_add_override(unsigned long mfn, struct page *page, 
	 * because mfn_to_pfn (that ends up being called by GUPF) will

	 * return the backend pfn rather than the frontend pfn. */

	pfn = mfn_to_pfn_no_overrides(mfn);

	if (get_phys_to_machine(pfn) == mfn)

	if (__pfn_to_mfn(pfn) == mfn)

		set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));



	return 0;
@@ -967,7 +967,7 @@ static int m2p_remove_override(struct page *page, 
	 * pfn again. */

	mfn &= ~FOREIGN_FRAME_BIT;

	pfn = mfn_to_pfn_no_overrides(mfn);

	if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&

	if (__pfn_to_mfn(pfn) == FOREIGN_FRAME(mfn) &&

			m2p_find_override(mfn) == NULL)

		set_phys_to_machine(pfn, mfn);
@@ -992,7 +992,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
	}



	for (i = 0; i < count; i++) {

		unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i]));

		unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));

		unsigned long pfn = page_to_pfn(pages[i]);



		if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {