[PATCH 0/8] Use correctly the Xen memory terminologies in Linux

[PATCH 0/8] Use correctly the Xen memory terminologies in Linux

[Julien Grall]

Hi all,

This patch series aims to use the memory terminologies described in
include/linux/mm.h [1] for Linux xen code.

Linux is using mistakenly MFN when GFN is meant, I suspect this is because the
first support of Xen was for PV. This has brought some misimplementation
of memory helpers on ARM and make the developper confused about the expected
behavior.

For instance, with pfn_to_mfn, we expect to get a MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.
Most of the callers are also using it this way.

The first 2 patches of this series is ARM related in order to remove
PV specific helpers which should not be used and fixing the implementation of
pfn_to_mfn.

The rest of the series is here rename most of the usage in the common code
of MFN to GFN. I also took the opportunity to replace most of the call to
pfn_to_gfn in the common code by page_to_gfn avoid construction such
as pfn_to_gfn(page_to_pfn(...).

Note the one xen-blkfront will be dropped by 64K series [2], I can include it
if necessary.

This series is based on Linux 4.2-rc4. A branch with all the patches
can be found here:
    git://xenbits.xen.org/people/julieng/linux-arm.git branch page-renaming-v1

Sincerely yours,

[1] Xen tree: e758ed14f390342513405dd766e874934573e6cb
[2] https://lkml.org/lkml/2015/7/9/628

Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <JBottomley@odin.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: linux-api@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-input@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-scsi@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: x86@kernel.org

Julien Grall (8):
  arm/xen: Remove helpers which are PV specific
  xen: Make clear that swiotlb and biomerge are dealing with DMA address
  arm/xen: implement correctly pfn_to_mfn
  xen: Use the correctly the Xen memory terminologies
  xen/tmem: Use page_to_gfn rather than pfn_to_gfn
  video/xen-fbfront: Further s/MFN/GFN clean-up
  hvc/xen: Further s/MFN/GFN clean-up
  xen/privcmd: Further s/MFN/GFN/ clean-up

 arch/arm/include/asm/xen/page.h         | 44 +++++++++++++++---------------
 arch/arm/xen/enlighten.c                | 18 ++++++-------
 arch/arm/xen/mm.c                       |  4 +--
 arch/x86/include/asm/xen/page.h         | 34 +++++++++++++----------
 arch/x86/xen/enlighten.c                |  4 +--
 arch/x86/xen/mmu.c                      | 48 ++++++++++++++++-----------------
 arch/x86/xen/p2m.c                      | 32 +++++++++++-----------
 arch/x86/xen/setup.c                    | 12 ++++-----
 arch/x86/xen/smp.c                      |  4 +--
 arch/x86/xen/suspend.c                  |  8 +++---
 drivers/block/xen-blkfront.c            |  6 ++---
 drivers/input/misc/xen-kbdfront.c       |  4 +--
 drivers/net/xen-netback/netback.c       |  4 +--
 drivers/net/xen-netfront.c              |  8 +++---
 drivers/scsi/xen-scsifront.c            |  8 +++---
 drivers/tty/hvc/hvc_xen.c               | 18 +++++--------
 drivers/video/fbdev/xen-fbfront.c       | 20 +++++++-------
 drivers/xen/balloon.c                   |  2 +-
 drivers/xen/biomerge.c                  |  6 ++---
 drivers/xen/events/events_base.c        |  2 +-
 drivers/xen/events/events_fifo.c        |  4 +--
 drivers/xen/gntalloc.c                  |  3 ++-
 drivers/xen/manage.c                    |  2 +-
 drivers/xen/privcmd.c                   | 44 +++++++++++++++---------------
 drivers/xen/swiotlb-xen.c               | 16 +++++------
 drivers/xen/tmem.c                      | 21 +++++----------
 drivers/xen/xenbus/xenbus_client.c      |  2 +-
 drivers/xen/xenbus/xenbus_dev_backend.c |  2 +-
 drivers/xen/xenbus/xenbus_probe.c       |  8 +++---
 drivers/xen/xlate_mmu.c                 | 18 ++++++-------
 include/uapi/xen/privcmd.h              |  4 +++
 include/xen/page.h                      |  4 +--
 include/xen/xen-ops.h                   | 10 +++----
 33 files changed, 210 insertions(+), 214 deletions(-)

-- 
2.1.4

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[PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This brough some misimplementation of helpers on ARM and make the
developper confused the expected behavior.

For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.

For clarity and avoid new confusion, replace any reference of mfn into
gnf in any helpers used by PV drivers.

Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up
will come in follow-up patches.

I think it may be possible to do further clean up in the x86 code to
ensure that helpers returning machine address (such as virt_address) is
not used by no auto-translated guests. I will let x86 xen expert doing
it.

[1] Xen tree: e758ed14f390342513405dd766e874934573e6cb

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "James E.J. Bottomley" <JBottomley@odin.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-input@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm/include/asm/xen/page.h         | 13 +++++++------
 arch/x86/include/asm/xen/page.h         | 30 ++++++++++++++++--------------
 arch/x86/xen/enlighten.c                |  4 ++--
 arch/x86/xen/mmu.c                      | 16 ++++++++--------
 arch/x86/xen/p2m.c                      | 32 ++++++++++++++++----------------
 arch/x86/xen/setup.c                    | 12 ++++++------
 arch/x86/xen/smp.c                      |  4 ++--
 arch/x86/xen/suspend.c                  |  8 ++++----
 drivers/block/xen-blkfront.c            |  6 +++---
 drivers/input/misc/xen-kbdfront.c       |  4 ++--
 drivers/net/xen-netback/netback.c       |  4 ++--
 drivers/net/xen-netfront.c              |  8 ++++----
 drivers/scsi/xen-scsifront.c            |  8 +++-----
 drivers/tty/hvc/hvc_xen.c               |  5 +++--
 drivers/video/fbdev/xen-fbfront.c       |  4 ++--
 drivers/xen/balloon.c                   |  2 +-
 drivers/xen/events/events_base.c        |  2 +-
 drivers/xen/events/events_fifo.c        |  4 ++--
 drivers/xen/gntalloc.c                  |  3 ++-
 drivers/xen/manage.c                    |  2 +-
 drivers/xen/tmem.c                      |  4 ++--
 drivers/xen/xenbus/xenbus_client.c      |  2 +-
 drivers/xen/xenbus/xenbus_dev_backend.c |  2 +-
 drivers/xen/xenbus/xenbus_probe.c       |  8 +++-----
 include/xen/page.h                      |  4 ++--
 25 files changed, 96 insertions(+), 95 deletions(-)

diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 493471f..f542f68 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -34,14 +34,15 @@ typedef struct xpaddr {
 unsigned long __pfn_to_mfn(unsigned long pfn);
 extern struct rb_root phys_to_mach;
 
-static inline unsigned long pfn_to_mfn(unsigned long pfn)
+/* Pseudo-physical <-> Guest conversion */
+static inline unsigned long pfn_to_gfn(unsigned long pfn)
 {
 	return pfn;
 }
 
-static inline unsigned long mfn_to_pfn(unsigned long mfn)
+static inline unsigned long gfn_to_pfn(unsigned long gfn)
 {
-	return mfn;
+	return gfn;
 }
 
 /* Pseudo-physical <-> DMA conversion */
@@ -65,9 +66,9 @@ static inline unsigned long dfn_to_pfn(unsigned long dfn)
 
 #define dfn_to_local_pfn(dfn)	dfn_to_pfn(dfn)
 
-/* VIRT <-> MACHINE conversion */
-#define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
-#define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
+/* VIRT <-> GUEST conversion */
+#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
+#define gfn_to_virt(m)		(__va(gfn_to_pfn(m) << PAGE_SHIFT))
 
 /* Only used in PV code. However ARM guest is always assimilated as HVM. */
 static inline xmaddr_t arbitrary_virt_to_machine(void *vaddr)
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 046e91a..72d9f15 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -99,7 +99,7 @@ static inline unsigned long __pfn_to_mfn(unsigned long pfn)
 	return mfn;
 }
 
-static inline unsigned long pfn_to_mfn(unsigned long pfn)
+static inline unsigned long pfn_to_gfn(unsigned long pfn)
 {
 	unsigned long mfn;
 
@@ -145,23 +145,23 @@ static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
 	return pfn;
 }
 
-static inline unsigned long mfn_to_pfn(unsigned long mfn)
+static inline unsigned long gfn_to_pfn(unsigned long gfn)
 {
 	unsigned long pfn;
 
 	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return mfn;
+		return gfn;
 
-	pfn = mfn_to_pfn_no_overrides(mfn);
-	if (__pfn_to_mfn(pfn) != mfn)
+	pfn = mfn_to_pfn_no_overrides(gfn);
+	if (__pfn_to_mfn(pfn) != gfn)
 		pfn = ~0;
 
 	/*
 	 * pfn is ~0 if there are no entries in the m2p for mfn or the
 	 * entry doesn't map back to the mfn.
 	 */
-	if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
-		pfn = mfn;
+	if (pfn == ~0 && __pfn_to_mfn(gfn) == IDENTITY_FRAME(gfn))
+		pfn = gfn;
 
 	return pfn;
 }
@@ -169,18 +169,18 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
 {
 	unsigned offset = phys.paddr & ~PAGE_MASK;
-	return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
+	return XMADDR(PFN_PHYS(pfn_to_gfn(PFN_DOWN(phys.paddr))) | offset);
 }
 
 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
 {
 	unsigned offset = machine.maddr & ~PAGE_MASK;
-	return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
+	return XPADDR(PFN_PHYS(gfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
 }
 
 /* Pseudo-physical <-> DMA conversion */
-#define pfn_to_dfn(pfn)		pfn_to_mfn(pfn)
-#define dfn_to_pfn(dfn)		mfn_to_pfn(dfn)
+#define pfn_to_dfn(pfn)		pfn_to_gfn(pfn)
+#define dfn_to_pfn(dfn)		gfn_to_pfn(dfn)
 
 /*
  * We detect special mappings in one of two ways:
@@ -209,7 +209,7 @@ static inline unsigned long dfn_to_local_pfn(unsigned long mfn)
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return mfn;
 
-	pfn = mfn_to_pfn(mfn);
+	pfn = gfn_to_pfn(mfn);
 	if (__pfn_to_mfn(pfn) != mfn)
 		return -1; /* force !pfn_valid() */
 	return pfn;
@@ -218,8 +218,10 @@ static inline unsigned long dfn_to_local_pfn(unsigned long mfn)
 /* VIRT <-> MACHINE conversion */
 #define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))
 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
-#define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
-#define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
+
+/* VIRT <-> GUEST conversion */
+#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
+#define gfn_to_virt(m)		(__va(gfn_to_pfn(m) << PAGE_SHIFT))
 
 static inline unsigned long pte_mfn(pte_t pte)
 {
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0b95c9b..a519b1b 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -573,7 +573,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr)
 		BUG_ON(ptep == NULL);
 
 		pfn = pte_pfn(*ptep);
-		mfn = pfn_to_mfn(pfn);
+		mfn = pfn_to_gfn(pfn);
 		virt = __va(PFN_PHYS(pfn));
 
 		frames[f] = mfn;
@@ -610,7 +610,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
 		unsigned long pfn, mfn;
 
 		pfn = virt_to_pfn(va);
-		mfn = pfn_to_mfn(pfn);
+		mfn = pfn_to_gfn(pfn);
 
 		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
 
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dd151b2..742b8d2 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -367,7 +367,7 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
 {
 	if (val & _PAGE_PRESENT) {
 		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
-		unsigned long pfn = mfn_to_pfn(mfn);
+		unsigned long pfn = gfn_to_pfn(mfn);
 
 		pteval_t flags = val & PTE_FLAGS_MASK;
 		if (unlikely(pfn == ~0))
@@ -730,7 +730,7 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
 	struct mmuext_op op;
 
 	op.cmd = level;
-	op.arg1.mfn = pfn_to_mfn(pfn);
+	op.arg1.mfn = pfn_to_gfn(pfn);
 
 	xen_extend_mmuext_op(&op);
 }
@@ -1323,7 +1323,7 @@ static void __xen_write_cr3(bool kernel, unsigned long cr3)
 	trace_xen_mmu_write_cr3(kernel, cr3);
 
 	if (cr3)
-		mfn = pfn_to_mfn(PFN_DOWN(cr3));
+		mfn = pfn_to_gfn(PFN_DOWN(cr3));
 	else
 		mfn = 0;
 
@@ -1493,7 +1493,7 @@ static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
 {
 	struct mmuext_op op;
 	op.cmd = cmd;
-	op.arg1.mfn = pfn_to_mfn(pfn);
+	op.arg1.mfn = pfn_to_gfn(pfn);
 	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
 		BUG();
 }
@@ -1539,7 +1539,7 @@ static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
 	mcs = __xen_mc_entry(sizeof(*op));
 	op = mcs.args;
 	op->cmd = cmd;
-	op->arg1.mfn = pfn_to_mfn(pfn);
+	op->arg1.mfn = pfn_to_gfn(pfn);
 
 	MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
 }
@@ -1672,7 +1672,7 @@ static unsigned long __init m2p(phys_addr_t maddr)
 	phys_addr_t paddr;
 
 	maddr &= PTE_PFN_MASK;
-	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
+	paddr = gfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
 
 	return paddr;
 }
@@ -2178,7 +2178,7 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
 		mcs = __xen_mc_entry(0);
 
 		if (in_frames)
-			in_frames[i] = virt_to_mfn(vaddr);
+			in_frames[i] = virt_to_gfn(vaddr);
 
 		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
 		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
@@ -2343,7 +2343,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
 	spin_lock_irqsave(&xen_reservation_lock, flags);
 
 	/* 1. Find start MFN of contiguous extent. */
-	in_frame = virt_to_mfn(vstart);
+	in_frame = virt_to_gfn(vstart);
 
 	/* 2. Zap current PTEs. */
 	xen_zap_pfn_range(vstart, order, NULL, out_frames);
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8b7f18e..9d23992d 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -30,14 +30,14 @@
  * However not all entries are filled with MFNs. Specifically for all other
  * leaf entries, or for the top  root, or middle one, for which there is a void
  * entry, we assume it is  "missing". So (for example)
- *  pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
+ *  pfn_to_gfn(0x90909090)=INVALID_P2M_ENTRY.
  * We have a dedicated page p2m_missing with all entries being
  * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
  * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
  *
  * We also have the possibility of setting 1-1 mappings on certain regions, so
  * that:
- *  pfn_to_mfn(0xc0000)=0xc0000
+ *  pfn_to_gfn(0xc0000)=0xc0000
  *
  * The benefit of this is, that we can assume for non-RAM regions (think
  * PCI BARs, or ACPI spaces), we can create mappings easily because we
@@ -51,10 +51,10 @@
  * identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
  * If the entry points to an allocated page, we just proceed as before and
  * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
- * appropriate functions (pfn_to_mfn).
+ * appropriate functions (pfn_to_gfn).
  *
  * The reason for having the IDENTITY_FRAME_BIT instead of just returning the
- * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
+ * PFN is that we could find ourselves where pfn_to_gfn(pfn)==pfn for a
  * non-identity pfn. To protect ourselves against we elect to set (and get) the
  * IDENTITY_FRAME_BIT on all identity mapped PFNs.
  */
@@ -129,7 +129,7 @@ static void p2m_top_mfn_init(unsigned long *top)
 	unsigned i;
 
 	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
-		top[i] = virt_to_mfn(p2m_mid_missing_mfn);
+		top[i] = virt_to_gfn(p2m_mid_missing_mfn);
 }
 
 static void p2m_top_mfn_p_init(unsigned long **top)
@@ -145,7 +145,7 @@ static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
 	unsigned i;
 
 	for (i = 0; i < P2M_MID_PER_PAGE; i++)
-		mid[i] = virt_to_mfn(leaf);
+		mid[i] = virt_to_gfn(leaf);
 }
 
 static void p2m_init(unsigned long *p2m)
@@ -236,7 +236,7 @@ void __ref xen_build_mfn_list_list(void)
 		if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
 			BUG_ON(mididx);
 			BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
-			p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
+			p2m_top_mfn[topidx] = virt_to_gfn(p2m_mid_missing_mfn);
 			pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
 			continue;
 		}
@@ -248,7 +248,7 @@ void __ref xen_build_mfn_list_list(void)
 			p2m_top_mfn_p[topidx] = mid_mfn_p;
 		}
 
-		p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+		p2m_top_mfn[topidx] = virt_to_gfn(mid_mfn_p);
 		mid_mfn_p[mididx] = mfn;
 	}
 }
@@ -261,7 +261,7 @@ void xen_setup_mfn_list_list(void)
 	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 
 	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
-		virt_to_mfn(p2m_top_mfn);
+		virt_to_gfn(p2m_top_mfn);
 	HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
 }
 
@@ -531,7 +531,7 @@ static bool alloc_p2m(unsigned long pfn)
 		top_mfn_p = &p2m_top_mfn[topidx];
 		mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
 
-		BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
+		BUG_ON(virt_to_gfn(mid_mfn) != *top_mfn_p);
 
 		if (mid_mfn == p2m_mid_missing_mfn) {
 			/* Separately check the mid mfn level */
@@ -545,12 +545,12 @@ static bool alloc_p2m(unsigned long pfn)
 
 			p2m_mid_mfn_init(mid_mfn, p2m_missing);
 
-			missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
-			mid_mfn_mfn = virt_to_mfn(mid_mfn);
+			missing_mfn = virt_to_gfn(p2m_mid_missing_mfn);
+			mid_mfn_mfn = virt_to_gfn(mid_mfn);
 			old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
 			if (old_mfn != missing_mfn) {
 				free_p2m_page(mid_mfn);
-				mid_mfn = mfn_to_virt(old_mfn);
+				mid_mfn = gfn_to_virt(old_mfn);
 			} else {
 				p2m_top_mfn_p[topidx] = mid_mfn;
 			}
@@ -580,7 +580,7 @@ static bool alloc_p2m(unsigned long pfn)
 			set_pte(ptep,
 				pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
 			if (mid_mfn)
-				mid_mfn[mididx] = virt_to_mfn(p2m);
+				mid_mfn[mididx] = virt_to_gfn(p2m);
 			p2m = NULL;
 		}
 
@@ -682,7 +682,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 			continue;
 
 		if (map_ops[i].flags & GNTMAP_contains_pte) {
-			pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
+			pte = (pte_t *)(gfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
 				(map_ops[i].host_addr & ~PAGE_MASK));
 			mfn = pte_mfn(*pte);
 		} else {
@@ -690,7 +690,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 		}
 		pfn = page_to_pfn(pages[i]);
 
-		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
+		WARN(pfn_to_gfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
 
 		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
 			ret = -ENOMEM;
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 55f388e..4c2e91d 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -231,10 +231,10 @@ static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
 	/* Release pages first. */
 	end = min(end_pfn, nr_pages);
 	for (pfn = start_pfn; pfn < end; pfn++) {
-		unsigned long mfn = pfn_to_mfn(pfn);
+		unsigned long mfn = pfn_to_gfn(pfn);
 
 		/* Make sure pfn exists to start with */
-		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
+		if (mfn == INVALID_P2M_ENTRY || gfn_to_pfn(mfn) != pfn)
 			continue;
 
 		ret = xen_free_mfn(mfn);
@@ -313,7 +313,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
 
 	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
 
-	mfn_save = virt_to_mfn(buf);
+	mfn_save = virt_to_gfn(buf);
 
 	for (ident_pfn_iter = start_pfn, remap_pfn_iter = remap_pfn;
 	     ident_pfn_iter < ident_end_pfn;
@@ -321,7 +321,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
 		chunk = (left < REMAP_SIZE) ? left : REMAP_SIZE;
 
 		/* Map first pfn to xen_remap_buf */
-		mfn = pfn_to_mfn(ident_pfn_iter);
+		mfn = pfn_to_gfn(ident_pfn_iter);
 		set_pte_mfn(buf, mfn, PAGE_KERNEL);
 
 		/* Save mapping information in page */
@@ -329,7 +329,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
 		xen_remap_buf.target_pfn = remap_pfn_iter;
 		xen_remap_buf.size = chunk;
 		for (i = 0; i < chunk; i++)
-			xen_remap_buf.mfns[i] = pfn_to_mfn(ident_pfn_iter + i);
+			xen_remap_buf.mfns[i] = pfn_to_gfn(ident_pfn_iter + i);
 
 		/* Put remap buf into list. */
 		xen_remap_mfn = mfn;
@@ -473,7 +473,7 @@ void __init xen_remap_memory(void)
 	unsigned long pfn_s = ~0UL;
 	unsigned long len = 0;
 
-	mfn_save = virt_to_mfn(buf);
+	mfn_save = virt_to_gfn(buf);
 
 	while (xen_remap_mfn != INVALID_P2M_ENTRY) {
 		/* Map the remap information */
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 8648438..680f281 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -395,7 +395,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
 
 		gdt_mfn = arbitrary_virt_to_mfn(gdt);
 		make_lowmem_page_readonly(gdt);
-		make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
+		make_lowmem_page_readonly(gfn_to_virt(gdt_mfn));
 
 		ctxt->gdt_frames[0] = gdt_mfn;
 		ctxt->gdt_ents      = GDT_ENTRIES;
@@ -429,7 +429,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
 	}
 #endif
 	ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
-	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
+	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
 	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
 		BUG();
 
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 53b4c08..60624e7 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -16,9 +16,9 @@ static void xen_pv_pre_suspend(void)
 {
 	xen_mm_pin_all();
 
-	xen_start_info->store_mfn = mfn_to_pfn(xen_start_info->store_mfn);
+	xen_start_info->store_mfn = gfn_to_pfn(xen_start_info->store_mfn);
 	xen_start_info->console.domU.mfn =
-		mfn_to_pfn(xen_start_info->console.domU.mfn);
+		gfn_to_pfn(xen_start_info->console.domU.mfn);
 
 	BUG_ON(!irqs_disabled());
 
@@ -51,9 +51,9 @@ static void xen_pv_post_suspend(int suspend_cancelled)
 
 	if (suspend_cancelled) {
 		xen_start_info->store_mfn =
-			pfn_to_mfn(xen_start_info->store_mfn);
+			pfn_to_gfn(xen_start_info->store_mfn);
 		xen_start_info->console.domU.mfn =
-			pfn_to_mfn(xen_start_info->console.domU.mfn);
+			pfn_to_gfn(xen_start_info->console.domU.mfn);
 	} else {
 #ifdef CONFIG_SMP
 		BUG_ON(xen_cpu_initialized_map == NULL);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 6d89ed3..2e541a4 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -247,7 +247,7 @@ static struct grant *get_grant(grant_ref_t *gref_head,
                                struct blkfront_info *info)
 {
 	struct grant *gnt_list_entry;
-	unsigned long buffer_mfn;
+	unsigned long buffer_gfn;
 
 	BUG_ON(list_empty(&info->grants));
 	gnt_list_entry = list_first_entry(&info->grants, struct grant,
@@ -266,10 +266,10 @@ static struct grant *get_grant(grant_ref_t *gref_head,
 		BUG_ON(!pfn);
 		gnt_list_entry->pfn = pfn;
 	}
-	buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
+	buffer_gfn = pfn_to_gfn(gnt_list_entry->pfn);
 	gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
 	                                info->xbdev->otherend_id,
-	                                buffer_mfn, 0);
+	                                buffer_gfn, 0);
 	return gnt_list_entry;
 }
 
diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index 95599e4..23d0549 100644
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -232,7 +232,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev,
 	struct xenbus_transaction xbt;
 
 	ret = gnttab_grant_foreign_access(dev->otherend_id,
-	                                  virt_to_mfn(info->page), 0);
+	                                  virt_to_gfn(info->page), 0);
 	if (ret < 0)
 		return ret;
 	info->gref = ret;
@@ -255,7 +255,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev,
 		goto error_irqh;
 	}
 	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
-			    virt_to_mfn(info->page));
+			    virt_to_gfn(info->page));
 	if (ret)
 		goto error_xenbus;
 	ret = xenbus_printf(xbt, dev->nodename, "page-gref", "%u", info->gref);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 7d50711..3b7b7c3 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
 		} else {
 			copy_gop->source.domid = DOMID_SELF;
 			copy_gop->source.u.gmfn =
-				virt_to_mfn(page_address(page));
+				virt_to_gfn(page_address(page));
 		}
 		copy_gop->source.offset = offset;
 
@@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 
 		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
-			virt_to_mfn(skb->data);
+			virt_to_gfn(skb->data);
 		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 		queue->tx_copy_ops[*copy_ops].dest.offset =
 			offset_in_page(skb->data);
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index f948c46..5cdab73 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -291,7 +291,7 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 		struct sk_buff *skb;
 		unsigned short id;
 		grant_ref_t ref;
-		unsigned long pfn;
+		unsigned long gfn;
 		struct xen_netif_rx_request *req;
 
 		skb = xennet_alloc_one_rx_buffer(queue);
@@ -307,12 +307,12 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 		BUG_ON((signed short)ref < 0);
 		queue->grant_rx_ref[id] = ref;
 
-		pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
+		gfn = page_to_gfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 
 		req = RING_GET_REQUEST(&queue->rx, req_prod);
 		gnttab_grant_foreign_access_ref(ref,
 						queue->info->xbdev->otherend_id,
-						pfn_to_mfn(pfn),
+						gfn,
 						0);
 
 		req->id = id;
@@ -431,7 +431,7 @@ static struct xen_netif_tx_request *xennet_make_one_txreq(
 	BUG_ON((signed short)ref < 0);
 
 	gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
-					page_to_mfn(page), GNTMAP_readonly);
+					page_to_gfn(page), GNTMAP_readonly);
 
 	queue->tx_skbs[id].skb = skb;
 	queue->grant_tx_page[id] = page;
diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index fad22ca..cdf00d1 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -377,7 +377,6 @@ static int map_data_for_request(struct vscsifrnt_info *info,
 	unsigned int data_len = scsi_bufflen(sc);
 	unsigned int data_grants = 0, seg_grants = 0;
 	struct scatterlist *sg;
-	unsigned long mfn;
 	struct scsiif_request_segment *seg;
 
 	ring_req->nr_segments = 0;
@@ -420,9 +419,8 @@ static int map_data_for_request(struct vscsifrnt_info *info,
 			ref = gnttab_claim_grant_reference(&gref_head);
 			BUG_ON(ref == -ENOSPC);
 
-			mfn = pfn_to_mfn(page_to_pfn(page));
 			gnttab_grant_foreign_access_ref(ref,
-				info->dev->otherend_id, mfn, 1);
+				info->dev->otherend_id, page_to_gfn(page), 1);
 			shadow->gref[ref_cnt] = ref;
 			ring_req->seg[ref_cnt].gref   = ref;
 			ring_req->seg[ref_cnt].offset = (uint16_t)off;
@@ -454,9 +452,9 @@ static int map_data_for_request(struct vscsifrnt_info *info,
 			ref = gnttab_claim_grant_reference(&gref_head);
 			BUG_ON(ref == -ENOSPC);
 
-			mfn = pfn_to_mfn(page_to_pfn(page));
 			gnttab_grant_foreign_access_ref(ref,
-				info->dev->otherend_id, mfn, grant_ro);
+				info->dev->otherend_id, page_to_gfn(page),
+				grant_ro);
 
 			shadow->gref[ref_cnt] = ref;
 			seg->gref   = ref;
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index a9d837f..efe5124 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -265,7 +265,8 @@ static int xen_pv_console_init(void)
 		return 0;
 	}
 	info->evtchn = xen_start_info->console.domU.evtchn;
-	info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
+	/* GFN == MFN for PV guest */
+	info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
 	info->vtermno = HVC_COOKIE;
 
 	spin_lock(&xencons_lock);
@@ -390,7 +391,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
 	if (IS_ERR(info->hvc))
 		return PTR_ERR(info->hvc);
 	if (xen_pv_domain())
-		mfn = virt_to_mfn(info->intf);
+		mfn = virt_to_gfn(info->intf);
 	else
 		mfn = __pa(info->intf) >> PAGE_SHIFT;
 	ret = gnttab_alloc_grant_references(1, &gref_head);
diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 09dc447..25e3cce 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -539,7 +539,7 @@ static int xenfb_remove(struct xenbus_device *dev)
 
 static unsigned long vmalloc_to_mfn(void *address)
 {
-	return pfn_to_mfn(vmalloc_to_pfn(address));
+	return pfn_to_gfn(vmalloc_to_pfn(address));
 }
 
 static void xenfb_init_shared_page(struct xenfb_info *info,
@@ -586,7 +586,7 @@ static int xenfb_connect_backend(struct xenbus_device *dev,
 		goto unbind_irq;
 	}
 	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
-			    virt_to_mfn(info->page));
+			    virt_to_gfn(info->page));
 	if (ret)
 		goto error_xenbus;
 	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index fd93369..9734649 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -441,7 +441,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 	/* Update direct mapping, invalidate P2M, and add to balloon. */
 	for (i = 0; i < nr_pages; i++) {
 		pfn = frame_list[i];
-		frame_list[i] = pfn_to_mfn(pfn);
+		frame_list[i] = pfn_to_gfn(pfn);
 		page = pfn_to_page(pfn);
 
 #ifdef CONFIG_XEN_HAVE_PVMMU
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 96093ae..95a4fdb 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1692,7 +1692,7 @@ void __init xen_init_IRQ(void)
 		struct physdev_pirq_eoi_gmfn eoi_gmfn;
 
 		pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
-		eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
+		eoi_gmfn.gmfn = virt_to_gfn(pirq_eoi_map);
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
 		/* TODO: No PVH support for PIRQ EOI */
 		if (rc != 0) {
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index ed673e1..1d4baf5 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -111,7 +111,7 @@ static int init_control_block(int cpu,
 	for (i = 0; i < EVTCHN_FIFO_MAX_QUEUES; i++)
 		q->head[i] = 0;
 
-	init_control.control_gfn = virt_to_mfn(control_block);
+	init_control.control_gfn = virt_to_gfn(control_block);
 	init_control.offset      = 0;
 	init_control.vcpu        = cpu;
 
@@ -167,7 +167,7 @@ static int evtchn_fifo_setup(struct irq_info *info)
 		/* Mask all events in this page before adding it. */
 		init_array_page(array_page);
 
-		expand_array.array_gfn = virt_to_mfn(array_page);
+		expand_array.array_gfn = virt_to_gfn(array_page);
 
 		ret = HYPERVISOR_event_channel_op(EVTCHNOP_expand_array, &expand_array);
 		if (ret < 0)
diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
index e53fe19..13e1458 100644
--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -142,7 +142,8 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
 
 		/* Grant foreign access to the page. */
 		rc = gnttab_grant_foreign_access(op->domid,
-			pfn_to_mfn(page_to_pfn(gref->page)), readonly);
+						 page_to_gfn(gref->page),
+						 readonly);
 		if (rc < 0)
 			goto undo;
 		gref_ids[i] = gref->gref_id = rc;
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index d10effe..e12bd36 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -80,7 +80,7 @@ static int xen_suspend(void *data)
 	 * is resuming in a new domain.
 	 */
 	si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
-                                           ? virt_to_mfn(xen_start_info)
+                                           ? virt_to_gfn(xen_start_info)
                                            : 0);
 
 	xen_arch_post_suspend(si->cancelled);
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 239738f..28c97ff 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -131,7 +131,7 @@ static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
 static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
 			     u32 index, unsigned long pfn)
 {
-	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
+	unsigned long gmfn = pfn_to_gfn(pfn);
 
 	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
 		gmfn, 0, 0, 0);
@@ -140,7 +140,7 @@ static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
 static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
 			     u32 index, unsigned long pfn)
 {
-	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
+	unsigned long gmfn = pfn_to_gfn(pfn);
 
 	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
 		gmfn, 0, 0, 0);
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 9ad3272..daa267a 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -380,7 +380,7 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
 
 	for (i = 0; i < nr_pages; i++) {
 		err = gnttab_grant_foreign_access(dev->otherend_id,
-						  virt_to_mfn(vaddr), 0);
+						  virt_to_gfn(vaddr), 0);
 		if (err < 0) {
 			xenbus_dev_fatal(dev, err,
 					 "granting access to ring page");
diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c
index b17707e..ee6d9ef 100644
--- a/drivers/xen/xenbus/xenbus_dev_backend.c
+++ b/drivers/xen/xenbus/xenbus_dev_backend.c
@@ -49,7 +49,7 @@ static long xenbus_alloc(domid_t domid)
 		goto out_err;
 
 	gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
-			virt_to_mfn(xen_store_interface), 0 /* writable */);
+			virt_to_gfn(xen_store_interface), 0 /* writable */);
 
 	arg.dom = DOMID_SELF;
 	arg.remote_dom = domid;
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 4308fb3..31836897 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -711,9 +711,7 @@ static int __init xenstored_local_init(void)
 	if (!page)
 		goto out_err;
 
-	xen_store_mfn = xen_start_info->store_mfn =
-		pfn_to_mfn(virt_to_phys((void *)page) >>
-			   PAGE_SHIFT);
+	xen_store_mfn = xen_start_info->store_mfn = virt_to_gfn(page);
 
 	/* Next allocate a local port which xenstored can bind to */
 	alloc_unbound.dom        = DOMID_SELF;
@@ -787,12 +785,12 @@ static int __init xenbus_init(void)
 		err = xenstored_local_init();
 		if (err)
 			goto out_error;
-		xen_store_interface = mfn_to_virt(xen_store_mfn);
+		xen_store_interface = gfn_to_virt(xen_store_mfn);
 		break;
 	case XS_PV:
 		xen_store_evtchn = xen_start_info->store_evtchn;
 		xen_store_mfn = xen_start_info->store_mfn;
-		xen_store_interface = mfn_to_virt(xen_store_mfn);
+		xen_store_interface = gfn_to_virt(xen_store_mfn);
 		break;
 	case XS_HVM:
 		err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
diff --git a/include/xen/page.h b/include/xen/page.h
index c5ed20b..e7e1425 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -3,9 +3,9 @@
 
 #include <asm/xen/page.h>
 
-static inline unsigned long page_to_mfn(struct page *page)
+static inline unsigned long page_to_gfn(struct page *page)
 {
-	return pfn_to_mfn(page_to_pfn(page));
+	return pfn_to_gfn(page_to_pfn(page));
 }
 
 struct xen_memory_region {
-- 
2.1.4

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[David Vrabel]

On 28/07/15 16:02, Julien Grall wrote:
> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
> is meant, I suspect this is because the first support for Xen was for
> PV. This brough some misimplementation of helpers on ARM and make the
> developper confused the expected behavior.

For the benefit of other subsystem maintainers, this is a purely
mechanical change in Xen-specific terminology.  It doesn't need reviews
or acks from non-Xen people (IMO).

> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
> Although, if we look at the implementation on x86, it's returning a GFN.
> 
> For clarity and avoid new confusion, replace any reference of mfn into
> gnf in any helpers used by PV drivers.
> 
> Take also the opportunity to simplify simple construction such
> as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up
> will come in follow-up patches.
> 
> I think it may be possible to do further clean up in the x86 code to
> ensure that helpers returning machine address (such as virt_address) is
> not used by no auto-translated guests. I will let x86 xen expert doing
> it.

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

It looks a bit odd to use GFN in some of the PV code where the
hypervisor API uses MFN but overall I think using the correct
terminology where possible is best.  But I'd like to have Boris's or
Konrad's opinion on this.

David

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 07/28/2015 11:02 AM, Julien Grall wrote:
> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
> is meant, I suspect this is because the first support for Xen was for
> PV. This brough some misimplementation of helpers on ARM and make the
> developper confused the expected behavior.
>
> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
> Although, if we look at the implementation on x86, it's returning a GFN.
>
> For clarity and avoid new confusion, replace any reference of mfn into
> gnf in any helpers used by PV drivers.




> @@ -730,7 +730,7 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
>   	struct mmuext_op op;
>
>   	op.cmd = level;
> -	op.arg1.mfn = pfn_to_mfn(pfn);
> +	op.arg1.mfn = pfn_to_gfn(pfn);


This looks slightly odd. It is correct but given that purpose of this 
series is to make things more clear perhaps we can add another union 
member (gfn) to mmuext_op.arg1?

(Of course, the hypervisor will continue referring to mfn which could 
still be confusing)


>
>   	xen_extend_mmuext_op(&op);
>   }
> @@ -1323,7 +1323,7 @@ static void __xen_write_cr3(bool kernel, unsigned long cr3)
>   	trace_xen_mmu_write_cr3(kernel, cr3);
>
>   	if (cr3)
> -		mfn = pfn_to_mfn(PFN_DOWN(cr3));
> +		mfn = pfn_to_gfn(PFN_DOWN(cr3));

Here too. And further down, thoughout this patch.




-boris

RE: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Chris (Christopher) Brand]

> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN is meant,
> I suspect this is because the first support for Xen was for PV. This brough some
Typo : "brought"
Perhaps "resulted in" would be better ?

> misimplementation of helpers on ARM and make the developper confused the expected behavior.
Typo: "developer".
I'd also suggest "...and confused developers about the...".

[...]

> For clarity and avoid new confusion, replace any reference of mfn into gnf in any helpers used by PV drivers.
Typo : "gfn"
I'd suggest "...replace any reference to mfn with gfn..."

[...]

Chris

Re: [PATCH 0/8] Use correctly the Xen memory terminologies in Linux

[H. Peter Anvin]

On 07/28/2015 08:02 AM, Julien Grall wrote:
> Hi all,
> 
> This patch series aims to use the memory terminologies described in
> include/linux/mm.h [1] for Linux xen code.
> 
> Linux is using mistakenly MFN when GFN is meant, I suspect this is because the
> first support of Xen was for PV. This has brought some misimplementation
> of memory helpers on ARM and make the developper confused about the expected
> behavior.
> 
> For instance, with pfn_to_mfn, we expect to get a MFN based on the name.
> Although, if we look at the implementation on x86, it's returning a GFN.
> Most of the callers are also using it this way.
> 
> The first 2 patches of this series is ARM related in order to remove
> PV specific helpers which should not be used and fixing the implementation of
> pfn_to_mfn.
> 
> The rest of the series is here rename most of the usage in the common code
> of MFN to GFN. I also took the opportunity to replace most of the call to
> pfn_to_gfn in the common code by page_to_gfn avoid construction such
> as pfn_to_gfn(page_to_pfn(...).
> 
> Note the one xen-blkfront will be dropped by 64K series [2], I can include it
> if necessary.
> 

Can we actually get some documentation for Xen before starting to change
names around?

	-hpa


_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [Xen-devel] [PATCH 0/8] Use correctly the Xen memory terminologies in Linux

[Andrew Cooper]

On 28/07/15 22:06, H. Peter Anvin wrote:
> On 07/28/2015 08:02 AM, Julien Grall wrote:
>> Hi all,
>>
>> This patch series aims to use the memory terminologies described in
>> include/linux/mm.h [1] for Linux xen code.
>>
>> Linux is using mistakenly MFN when GFN is meant, I suspect this is because the
>> first support of Xen was for PV. This has brought some misimplementation
>> of memory helpers on ARM and make the developper confused about the expected
>> behavior.
>>
>> For instance, with pfn_to_mfn, we expect to get a MFN based on the name.
>> Although, if we look at the implementation on x86, it's returning a GFN.
>> Most of the callers are also using it this way.
>>
>> The first 2 patches of this series is ARM related in order to remove
>> PV specific helpers which should not be used and fixing the implementation of
>> pfn_to_mfn.
>>
>> The rest of the series is here rename most of the usage in the common code
>> of MFN to GFN. I also took the opportunity to replace most of the call to
>> pfn_to_gfn in the common code by page_to_gfn avoid construction such
>> as pfn_to_gfn(page_to_pfn(...).
>>
>> Note the one xen-blkfront will be dropped by 64K series [2], I can include it
>> if necessary.
>>
> Can we actually get some documentation for Xen before starting to change
> names around?

http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb

~Andrew

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Wei Liu]

On Tue, Jul 28, 2015 at 04:02:45PM +0100, Julien Grall wrote:
[...]
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index 7d50711..3b7b7c3 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
>  		} else {
>  			copy_gop->source.domid = DOMID_SELF;
>  			copy_gop->source.u.gmfn =
> -				virt_to_mfn(page_address(page));
> +				virt_to_gfn(page_address(page));
>  		}
>  		copy_gop->source.offset = offset;
>  
> @@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
>  		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
>  
>  		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
> -			virt_to_mfn(skb->data);
> +			virt_to_gfn(skb->data);
>  		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
>  		queue->tx_copy_ops[*copy_ops].dest.offset =
>  			offset_in_page(skb->data);

Reviewed-by: Wei Liu <wei.liu2@citrix.com>

One possible improvement is to change gmfn in copy_gop to gfn as well.
But that's outside of netback code.

Wei.

Re: [PATCH 0/8] Use correctly the Xen memory terminologies in Linux

[Julien Grall]

On 28/07/15 16:02, Julien Grall wrote:
> Hi all,
> 
> This patch series aims to use the memory terminologies described in
> include/linux/mm.h [1] for Linux xen code.

I mistakenly wrote the wrong include here. It should be include/xen/mm.h
from the Xen tree:

http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

On 28/07/15 18:16, David Vrabel wrote:
> On 28/07/15 16:02, Julien Grall wrote:
>> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
>> is meant, I suspect this is because the first support for Xen was for
>> PV. This brough some misimplementation of helpers on ARM and make the
>> developper confused the expected behavior.
> 
> For the benefit of other subsystem maintainers, this is a purely
> mechanical change in Xen-specific terminology.  It doesn't need reviews
> or acks from non-Xen people (IMO).
> 
>> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
>> Although, if we look at the implementation on x86, it's returning a GFN.
>>
>> For clarity and avoid new confusion, replace any reference of mfn into
>> gnf in any helpers used by PV drivers.
>>
>> Take also the opportunity to simplify simple construction such
>> as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up
>> will come in follow-up patches.
>>
>> I think it may be possible to do further clean up in the x86 code to
>> ensure that helpers returning machine address (such as virt_address) is
>> not used by no auto-translated guests. I will let x86 xen expert doing
>> it.
> 
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
> 
> It looks a bit odd to use GFN in some of the PV code where the
> hypervisor API uses MFN but overall I think using the correct
> terminology where possible is best.  But I'd like to have Boris's or
> Konrad's opinion on this.

I was thinking to introduce mfn_to_pfn & co which would be used only for
PV-guest (a BUG_ON would be here to ensure it) and hypercall related.

I didn't do it as I haven't much knowledge on x86 Xen and was able to
decide where I have to use pfn_to_mfn.

Regards,

-- 
Julien Grall

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Hi Boris,

On 28/07/15 20:12, Boris Ostrovsky wrote:
> On 07/28/2015 11:02 AM, Julien Grall wrote:
>> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
>> is meant, I suspect this is because the first support for Xen was for
>> PV. This brough some misimplementation of helpers on ARM and make the
>> developper confused the expected behavior.
>>
>> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
>> Although, if we look at the implementation on x86, it's returning a GFN.
>>
>> For clarity and avoid new confusion, replace any reference of mfn into
>> gnf in any helpers used by PV drivers.
> 
> 
> 
> 
>> @@ -730,7 +730,7 @@ static void xen_do_pin(unsigned level, unsigned
>> long pfn)
>>       struct mmuext_op op;
>>
>>       op.cmd = level;
>> -    op.arg1.mfn = pfn_to_mfn(pfn);
>> +    op.arg1.mfn = pfn_to_gfn(pfn);
> 
> 
> This looks slightly odd. It is correct but given that purpose of this
> series is to make things more clear perhaps we can add another union
> member (gfn) to mmuext_op.arg1?
> 
> (Of course, the hypervisor will continue referring to mfn which could
> still be confusing)

This operation is only used for PV guests, right?

IHMO re-introducing pfn_to_mfn for PV-guests only (i.e with a BUG_ON to
ensure no usage for auto-translated guest) would be the best solution.
It would avoid to have different name than the hypersivor one in the
hypercall interface. It will also make clear that virt_to_machine & co
is only PV specific.

I though doing this but I preferred to defer it to x86 expert as my
knowledge for x86 Xen is very limited. I don't know where it's more
suitable to use MFN or GFN. I guess this file (mmu.c) is mostly PV specific?

Would something like below fine for you?

static inline unsigned long pfn_to_mfn(unsigned long pfn)
{
	unsigned long mfn;

	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));

	mfn = __pfn_to_mfn(pfn);
	if (mfn != INVALID_P2M_ENTRY)
		mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);

	return mfn;
}

static inline unsigned long pfn_to_gfn(unsigned long pfn)
{
	if (xen_feature(XENFEAT_autotranslated_physmap))
		return pfn;
	else
		return pfn_to_mfn(pfn);
}

Similar splitting would be done for gfn_to_pfn and mfn_to_pfn.

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Hi Chris,

On 28/07/15 20:39, Chris (Christopher) Brand wrote:
>> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN is meant,
>> I suspect this is because the first support for Xen was for PV. This brough some
> Typo : "brought"
> Perhaps "resulted in" would be better ?
> 
>> misimplementation of helpers on ARM and make the developper confused the expected behavior.
> Typo: "developer".
> I'd also suggest "...and confused developers about the...".
> 
> [...]
> 
>> For clarity and avoid new confusion, replace any reference of mfn into gnf in any helpers used by PV drivers.
> Typo : "gfn"
> I'd suggest "...replace any reference to mfn with gfn..."
> 
> [...]

Thanks for telling me the typoes. I will fix it in the next version of
this series.

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Hi Wei,

On 29/07/15 11:13, Wei Liu wrote:
> On Tue, Jul 28, 2015 at 04:02:45PM +0100, Julien Grall wrote:
> [...]
>> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
>> index 7d50711..3b7b7c3 100644
>> --- a/drivers/net/xen-netback/netback.c
>> +++ b/drivers/net/xen-netback/netback.c
>> @@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
>>  		} else {
>>  			copy_gop->source.domid = DOMID_SELF;
>>  			copy_gop->source.u.gmfn =
>> -				virt_to_mfn(page_address(page));
>> +				virt_to_gfn(page_address(page));
>>  		}
>>  		copy_gop->source.offset = offset;
>>  
>> @@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
>>  		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
>>  
>>  		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
>> -			virt_to_mfn(skb->data);
>> +			virt_to_gfn(skb->data);
>>  		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
>>  		queue->tx_copy_ops[*copy_ops].dest.offset =
>>  			offset_in_page(skb->data);
> 
> Reviewed-by: Wei Liu <wei.liu2@citrix.com>
> 
> One possible improvement is to change gmfn in copy_gop to gfn as well.
> But that's outside of netback code.

The structure gnttab_copy is part of the hypervisor interface. Is it
fine to differ on the naming between Xen and Linux?

Or maybe we could do the change in the public headers in Xen repo too.
Is it fine to do field renaming in public headers?

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[David Vrabel]

On 29/07/15 12:35, Julien Grall wrote:
> Hi Wei,
> 
> On 29/07/15 11:13, Wei Liu wrote:
>> On Tue, Jul 28, 2015 at 04:02:45PM +0100, Julien Grall wrote:
>> [...]
>>> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
>>> index 7d50711..3b7b7c3 100644
>>> --- a/drivers/net/xen-netback/netback.c
>>> +++ b/drivers/net/xen-netback/netback.c
>>> @@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
>>>  		} else {
>>>  			copy_gop->source.domid = DOMID_SELF;
>>>  			copy_gop->source.u.gmfn =
>>> -				virt_to_mfn(page_address(page));
>>> +				virt_to_gfn(page_address(page));
>>>  		}
>>>  		copy_gop->source.offset = offset;
>>>  
>>> @@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
>>>  		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
>>>  
>>>  		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
>>> -			virt_to_mfn(skb->data);
>>> +			virt_to_gfn(skb->data);
>>>  		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
>>>  		queue->tx_copy_ops[*copy_ops].dest.offset =
>>>  			offset_in_page(skb->data);
>>
>> Reviewed-by: Wei Liu <wei.liu2@citrix.com>
>>
>> One possible improvement is to change gmfn in copy_gop to gfn as well.
>> But that's outside of netback code.
> 
> The structure gnttab_copy is part of the hypervisor interface. Is it
> fine to differ on the naming between Xen and Linux?
> 
> Or maybe we could do the change in the public headers in Xen repo too.
> Is it fine to do field renaming in public headers?

I think this series should not alter than Xen API.

David

Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Wei Liu]

On Wed, Jul 29, 2015 at 12:35:54PM +0100, Julien Grall wrote:
> Hi Wei,
> 
> On 29/07/15 11:13, Wei Liu wrote:
> > On Tue, Jul 28, 2015 at 04:02:45PM +0100, Julien Grall wrote:
> > [...]
> >> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> >> index 7d50711..3b7b7c3 100644
> >> --- a/drivers/net/xen-netback/netback.c
> >> +++ b/drivers/net/xen-netback/netback.c
> >> @@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
> >>  		} else {
> >>  			copy_gop->source.domid = DOMID_SELF;
> >>  			copy_gop->source.u.gmfn =
> >> -				virt_to_mfn(page_address(page));
> >> +				virt_to_gfn(page_address(page));
> >>  		}
> >>  		copy_gop->source.offset = offset;
> >>  
> >> @@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
> >>  		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
> >>  
> >>  		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
> >> -			virt_to_mfn(skb->data);
> >> +			virt_to_gfn(skb->data);
> >>  		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
> >>  		queue->tx_copy_ops[*copy_ops].dest.offset =
> >>  			offset_in_page(skb->data);
> > 
> > Reviewed-by: Wei Liu <wei.liu2@citrix.com>
> > 
> > One possible improvement is to change gmfn in copy_gop to gfn as well.
> > But that's outside of netback code.
> 
> The structure gnttab_copy is part of the hypervisor interface. Is it
> fine to differ on the naming between Xen and Linux?
> 
> Or maybe we could do the change in the public headers in Xen repo too.
> Is it fine to do field renaming in public headers?
> 

Oh well. Never mind then. I mistook that structure as internal to Linux.

Wei.

> Regards,
> 
> -- 
> Julien Grall

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 07/29/2015 07:25 AM, Julien Grall wrote:
> Hi Boris,
>
> On 28/07/15 20:12, Boris Ostrovsky wrote:
>> On 07/28/2015 11:02 AM, Julien Grall wrote:
>>> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
>>> is meant, I suspect this is because the first support for Xen was for
>>> PV. This brough some misimplementation of helpers on ARM and make the
>>> developper confused the expected behavior.
>>>
>>> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
>>> Although, if we look at the implementation on x86, it's returning a GFN.
>>>
>>> For clarity and avoid new confusion, replace any reference of mfn into
>>> gnf in any helpers used by PV drivers.
>>
>>
>>
>>
>>> @@ -730,7 +730,7 @@ static void xen_do_pin(unsigned level, unsigned
>>> long pfn)
>>>        struct mmuext_op op;
>>>
>>>        op.cmd = level;
>>> -    op.arg1.mfn = pfn_to_mfn(pfn);
>>> +    op.arg1.mfn = pfn_to_gfn(pfn);
>>
>>
>> This looks slightly odd. It is correct but given that purpose of this
>> series is to make things more clear perhaps we can add another union
>> member (gfn) to mmuext_op.arg1?
>>
>> (Of course, the hypervisor will continue referring to mfn which could
>> still be confusing)
>
> This operation is only used for PV guests, right?
>
> IHMO re-introducing pfn_to_mfn for PV-guests only (i.e with a BUG_ON to
> ensure no usage for auto-translated guest) would be the best solution.
> It would avoid to have different name than the hypersivor one in the
> hypercall interface. It will also make clear that virt_to_machine & co
> is only PV specific.
>
> I though doing this but I preferred to defer it to x86 expert as my
> knowledge for x86 Xen is very limited. I don't know where it's more
> suitable to use MFN or GFN. I guess this file (mmu.c) is mostly PV specific?
>
> Would something like below fine for you?
>
> static inline unsigned long pfn_to_mfn(unsigned long pfn)
> {
> 	unsigned long mfn;
>
> 	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
>
> 	mfn = __pfn_to_mfn(pfn);
> 	if (mfn != INVALID_P2M_ENTRY)
> 		mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
>
> 	return mfn;
> }
>
> static inline unsigned long pfn_to_gfn(unsigned long pfn)
> {
> 	if (xen_feature(XENFEAT_autotranslated_physmap))
> 		return pfn;
> 	else
> 		return pfn_to_mfn(pfn);
> }


But you'd still say 'op.arg1.mfn = pfn_to_gfn(pfn);' in xen_do_pin() 
i.e. assign GFN to MFN, right? That's what I was referring to.

(In general, I am not sure a guest should ever use 'mfn' as it is purely 
a hypervisor construct. Including p2m, which I think should really be 
p2g as this is what we use to figure out what to stick into page tables)

-boris


>
> Similar splitting would be done for gfn_to_pfn and mfn_to_pfn.
>
> Regards,
>

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

On 29/07/15 15:14, Boris Ostrovsky wrote:
>> static inline unsigned long pfn_to_gfn(unsigned long pfn)
>> {
>>     if (xen_feature(XENFEAT_autotranslated_physmap))
>>         return pfn;
>>     else
>>         return pfn_to_mfn(pfn);
>> }
> 
> 
> But you'd still say 'op.arg1.mfn = pfn_to_gfn(pfn);' in xen_do_pin()
> i.e. assign GFN to MFN, right? That's what I was referring to.

Well no. I would use op.arg1.mfn = pfn_to_mfn(pfn) given that the code,
if I'm right, is only executed for PV.

mfn = pfn_to_gfn(...) was valid too because on PV is always an MFN. The
suggestion of pfn_to_mfn was just for more readability,

> (In general, I am not sure a guest should ever use 'mfn' as it is purely
> a hypervisor construct. Including p2m, which I think should really be
> p2g as this is what we use to figure out what to stick into page tables)

I think avoid to use mfn in the hypervisor interface is out-of-scope for
this series. If we ever want to modify the Xen API in Linux, we should
do in sync with Xen to avoid inconsistency on naming.

Anyway, the oddity of mfn = pfn_to_gfn(...) is mostly contained in the
x86 specific code. I don't mind to either add pfn_to_mfn and use it or
add a comment /* PV-specific so mfn == gfn */ for every use of mfn =
pfn_to_gfn(...).

Regards,

-- 
Julien Grall

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 07/29/2015 10:23 AM, Julien Grall wrote:
> On 29/07/15 15:14, Boris Ostrovsky wrote:
>>> static inline unsigned long pfn_to_gfn(unsigned long pfn)
>>> {
>>>      if (xen_feature(XENFEAT_autotranslated_physmap))
>>>          return pfn;
>>>      else
>>>          return pfn_to_mfn(pfn);
>>> }
>>
>> But you'd still say 'op.arg1.mfn = pfn_to_gfn(pfn);' in xen_do_pin()
>> i.e. assign GFN to MFN, right? That's what I was referring to.
> Well no. I would use op.arg1.mfn = pfn_to_mfn(pfn) given that the code,
> if I'm right, is only executed for PV.
>
> mfn = pfn_to_gfn(...) was valid too because on PV is always an MFN. The
> suggestion of pfn_to_mfn was just for more readability,

Right, and my comments were also not about correctness.


>
>> (In general, I am not sure a guest should ever use 'mfn' as it is purely
>> a hypervisor construct. Including p2m, which I think should really be
>> p2g as this is what we use to figure out what to stick into page tables)
> I think avoid to use mfn in the hypervisor interface is out-of-scope for
> this series. If we ever want to modify the Xen API in Linux, we should
> do in sync with Xen to avoid inconsistency on naming.
>
> Anyway, the oddity of mfn = pfn_to_gfn(...) is mostly contained in the
> x86 specific code. I don't mind to either add pfn_to_mfn and use it or
> add a comment /* PV-specific so mfn == gfn */ for every use of mfn =
> pfn_to_gfn(...).

I think the former is better (even thought it adds a test)

-boris

Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies

[Stefano Stabellini]

On Tue, 28 Jul 2015, Julien Grall wrote:
> Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
> is meant, I suspect this is because the first support for Xen was for
> PV. This brough some misimplementation of helpers on ARM and make the
> developper confused the expected behavior.
> 
> For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
> Although, if we look at the implementation on x86, it's returning a GFN.
> 
> For clarity and avoid new confusion, replace any reference of mfn into
> gnf in any helpers used by PV drivers.
> 
> Take also the opportunity to simplify simple construction such
> as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up
> will come in follow-up patches.
> 
> I think it may be possible to do further clean up in the x86 code to
> ensure that helpers returning machine address (such as virt_address) is
> not used by no auto-translated guests. I will let x86 xen expert doing
> it.
> 
> [1] Xen tree: e758ed14f390342513405dd766e874934573e6cb
> 
> Signed-off-by: Julien Grall <julien.grall@citrix.com>

Aside from the many typos

Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


>  arch/arm/include/asm/xen/page.h         | 13 +++++++------
>  arch/x86/include/asm/xen/page.h         | 30 ++++++++++++++++--------------
>  arch/x86/xen/enlighten.c                |  4 ++--
>  arch/x86/xen/mmu.c                      | 16 ++++++++--------
>  arch/x86/xen/p2m.c                      | 32 ++++++++++++++++----------------
>  arch/x86/xen/setup.c                    | 12 ++++++------
>  arch/x86/xen/smp.c                      |  4 ++--
>  arch/x86/xen/suspend.c                  |  8 ++++----
>  drivers/block/xen-blkfront.c            |  6 +++---
>  drivers/input/misc/xen-kbdfront.c       |  4 ++--
>  drivers/net/xen-netback/netback.c       |  4 ++--
>  drivers/net/xen-netfront.c              |  8 ++++----
>  drivers/scsi/xen-scsifront.c            |  8 +++-----
>  drivers/tty/hvc/hvc_xen.c               |  5 +++--
>  drivers/video/fbdev/xen-fbfront.c       |  4 ++--
>  drivers/xen/balloon.c                   |  2 +-
>  drivers/xen/events/events_base.c        |  2 +-
>  drivers/xen/events/events_fifo.c        |  4 ++--
>  drivers/xen/gntalloc.c                  |  3 ++-
>  drivers/xen/manage.c                    |  2 +-
>  drivers/xen/tmem.c                      |  4 ++--
>  drivers/xen/xenbus/xenbus_client.c      |  2 +-
>  drivers/xen/xenbus/xenbus_dev_backend.c |  2 +-
>  drivers/xen/xenbus/xenbus_probe.c       |  8 +++-----
>  include/xen/page.h                      |  4 ++--
>  25 files changed, 96 insertions(+), 95 deletions(-)
> 
> diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
> index 493471f..f542f68 100644
> --- a/arch/arm/include/asm/xen/page.h
> +++ b/arch/arm/include/asm/xen/page.h
> @@ -34,14 +34,15 @@ typedef struct xpaddr {
>  unsigned long __pfn_to_mfn(unsigned long pfn);
>  extern struct rb_root phys_to_mach;
>  
> -static inline unsigned long pfn_to_mfn(unsigned long pfn)
> +/* Pseudo-physical <-> Guest conversion */
> +static inline unsigned long pfn_to_gfn(unsigned long pfn)
>  {
>  	return pfn;
>  }
>  
> -static inline unsigned long mfn_to_pfn(unsigned long mfn)
> +static inline unsigned long gfn_to_pfn(unsigned long gfn)
>  {
> -	return mfn;
> +	return gfn;
>  }
>  
>  /* Pseudo-physical <-> DMA conversion */
> @@ -65,9 +66,9 @@ static inline unsigned long dfn_to_pfn(unsigned long dfn)
>  
>  #define dfn_to_local_pfn(dfn)	dfn_to_pfn(dfn)
>  
> -/* VIRT <-> MACHINE conversion */
> -#define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
> -#define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
> +/* VIRT <-> GUEST conversion */
> +#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
> +#define gfn_to_virt(m)		(__va(gfn_to_pfn(m) << PAGE_SHIFT))
>  
>  /* Only used in PV code. However ARM guest is always assimilated as HVM. */
>  static inline xmaddr_t arbitrary_virt_to_machine(void *vaddr)
> diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> index 046e91a..72d9f15 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -99,7 +99,7 @@ static inline unsigned long __pfn_to_mfn(unsigned long pfn)
>  	return mfn;
>  }
>  
> -static inline unsigned long pfn_to_mfn(unsigned long pfn)
> +static inline unsigned long pfn_to_gfn(unsigned long pfn)
>  {
>  	unsigned long mfn;
>  
> @@ -145,23 +145,23 @@ static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
>  	return pfn;
>  }
>  
> -static inline unsigned long mfn_to_pfn(unsigned long mfn)
> +static inline unsigned long gfn_to_pfn(unsigned long gfn)
>  {
>  	unsigned long pfn;
>  
>  	if (xen_feature(XENFEAT_auto_translated_physmap))
> -		return mfn;
> +		return gfn;
>  
> -	pfn = mfn_to_pfn_no_overrides(mfn);
> -	if (__pfn_to_mfn(pfn) != mfn)
> +	pfn = mfn_to_pfn_no_overrides(gfn);
> +	if (__pfn_to_mfn(pfn) != gfn)
>  		pfn = ~0;
>  
>  	/*
>  	 * pfn is ~0 if there are no entries in the m2p for mfn or the
>  	 * entry doesn't map back to the mfn.
>  	 */
> -	if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
> -		pfn = mfn;
> +	if (pfn == ~0 && __pfn_to_mfn(gfn) == IDENTITY_FRAME(gfn))
> +		pfn = gfn;
>  
>  	return pfn;
>  }
> @@ -169,18 +169,18 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
>  static inline xmaddr_t phys_to_machine(xpaddr_t phys)
>  {
>  	unsigned offset = phys.paddr & ~PAGE_MASK;
> -	return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
> +	return XMADDR(PFN_PHYS(pfn_to_gfn(PFN_DOWN(phys.paddr))) | offset);
>  }
>  
>  static inline xpaddr_t machine_to_phys(xmaddr_t machine)
>  {
>  	unsigned offset = machine.maddr & ~PAGE_MASK;
> -	return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
> +	return XPADDR(PFN_PHYS(gfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
>  }
>  
>  /* Pseudo-physical <-> DMA conversion */
> -#define pfn_to_dfn(pfn)		pfn_to_mfn(pfn)
> -#define dfn_to_pfn(dfn)		mfn_to_pfn(dfn)
> +#define pfn_to_dfn(pfn)		pfn_to_gfn(pfn)
> +#define dfn_to_pfn(dfn)		gfn_to_pfn(dfn)
>  
>  /*
>   * We detect special mappings in one of two ways:
> @@ -209,7 +209,7 @@ static inline unsigned long dfn_to_local_pfn(unsigned long mfn)
>  	if (xen_feature(XENFEAT_auto_translated_physmap))
>  		return mfn;
>  
> -	pfn = mfn_to_pfn(mfn);
> +	pfn = gfn_to_pfn(mfn);
>  	if (__pfn_to_mfn(pfn) != mfn)
>  		return -1; /* force !pfn_valid() */
>  	return pfn;
> @@ -218,8 +218,10 @@ static inline unsigned long dfn_to_local_pfn(unsigned long mfn)
>  /* VIRT <-> MACHINE conversion */
>  #define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))
>  #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
> -#define virt_to_mfn(v)		(pfn_to_mfn(virt_to_pfn(v)))
> -#define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
> +
> +/* VIRT <-> GUEST conversion */
> +#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
> +#define gfn_to_virt(m)		(__va(gfn_to_pfn(m) << PAGE_SHIFT))
>  
>  static inline unsigned long pte_mfn(pte_t pte)
>  {
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 0b95c9b..a519b1b 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -573,7 +573,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr)
>  		BUG_ON(ptep == NULL);
>  
>  		pfn = pte_pfn(*ptep);
> -		mfn = pfn_to_mfn(pfn);
> +		mfn = pfn_to_gfn(pfn);
>  		virt = __va(PFN_PHYS(pfn));
>  
>  		frames[f] = mfn;
> @@ -610,7 +610,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
>  		unsigned long pfn, mfn;
>  
>  		pfn = virt_to_pfn(va);
> -		mfn = pfn_to_mfn(pfn);
> +		mfn = pfn_to_gfn(pfn);
>  
>  		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
>  
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index dd151b2..742b8d2 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -367,7 +367,7 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
>  {
>  	if (val & _PAGE_PRESENT) {
>  		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
> -		unsigned long pfn = mfn_to_pfn(mfn);
> +		unsigned long pfn = gfn_to_pfn(mfn);
>  
>  		pteval_t flags = val & PTE_FLAGS_MASK;
>  		if (unlikely(pfn == ~0))
> @@ -730,7 +730,7 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
>  	struct mmuext_op op;
>  
>  	op.cmd = level;
> -	op.arg1.mfn = pfn_to_mfn(pfn);
> +	op.arg1.mfn = pfn_to_gfn(pfn);
>  
>  	xen_extend_mmuext_op(&op);
>  }
> @@ -1323,7 +1323,7 @@ static void __xen_write_cr3(bool kernel, unsigned long cr3)
>  	trace_xen_mmu_write_cr3(kernel, cr3);
>  
>  	if (cr3)
> -		mfn = pfn_to_mfn(PFN_DOWN(cr3));
> +		mfn = pfn_to_gfn(PFN_DOWN(cr3));
>  	else
>  		mfn = 0;
>  
> @@ -1493,7 +1493,7 @@ static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
>  {
>  	struct mmuext_op op;
>  	op.cmd = cmd;
> -	op.arg1.mfn = pfn_to_mfn(pfn);
> +	op.arg1.mfn = pfn_to_gfn(pfn);
>  	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
>  		BUG();
>  }
> @@ -1539,7 +1539,7 @@ static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
>  	mcs = __xen_mc_entry(sizeof(*op));
>  	op = mcs.args;
>  	op->cmd = cmd;
> -	op->arg1.mfn = pfn_to_mfn(pfn);
> +	op->arg1.mfn = pfn_to_gfn(pfn);
>  
>  	MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
>  }
> @@ -1672,7 +1672,7 @@ static unsigned long __init m2p(phys_addr_t maddr)
>  	phys_addr_t paddr;
>  
>  	maddr &= PTE_PFN_MASK;
> -	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
> +	paddr = gfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
>  
>  	return paddr;
>  }
> @@ -2178,7 +2178,7 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
>  		mcs = __xen_mc_entry(0);
>  
>  		if (in_frames)
> -			in_frames[i] = virt_to_mfn(vaddr);
> +			in_frames[i] = virt_to_gfn(vaddr);
>  
>  		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
>  		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
> @@ -2343,7 +2343,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
>  	spin_lock_irqsave(&xen_reservation_lock, flags);
>  
>  	/* 1. Find start MFN of contiguous extent. */
> -	in_frame = virt_to_mfn(vstart);
> +	in_frame = virt_to_gfn(vstart);
>  
>  	/* 2. Zap current PTEs. */
>  	xen_zap_pfn_range(vstart, order, NULL, out_frames);
> diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> index 8b7f18e..9d23992d 100644
> --- a/arch/x86/xen/p2m.c
> +++ b/arch/x86/xen/p2m.c
> @@ -30,14 +30,14 @@
>   * However not all entries are filled with MFNs. Specifically for all other
>   * leaf entries, or for the top  root, or middle one, for which there is a void
>   * entry, we assume it is  "missing". So (for example)
> - *  pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
> + *  pfn_to_gfn(0x90909090)=INVALID_P2M_ENTRY.
>   * We have a dedicated page p2m_missing with all entries being
>   * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
>   * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
>   *
>   * We also have the possibility of setting 1-1 mappings on certain regions, so
>   * that:
> - *  pfn_to_mfn(0xc0000)=0xc0000
> + *  pfn_to_gfn(0xc0000)=0xc0000
>   *
>   * The benefit of this is, that we can assume for non-RAM regions (think
>   * PCI BARs, or ACPI spaces), we can create mappings easily because we
> @@ -51,10 +51,10 @@
>   * identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
>   * If the entry points to an allocated page, we just proceed as before and
>   * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
> - * appropriate functions (pfn_to_mfn).
> + * appropriate functions (pfn_to_gfn).
>   *
>   * The reason for having the IDENTITY_FRAME_BIT instead of just returning the
> - * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
> + * PFN is that we could find ourselves where pfn_to_gfn(pfn)==pfn for a
>   * non-identity pfn. To protect ourselves against we elect to set (and get) the
>   * IDENTITY_FRAME_BIT on all identity mapped PFNs.
>   */
> @@ -129,7 +129,7 @@ static void p2m_top_mfn_init(unsigned long *top)
>  	unsigned i;
>  
>  	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
> -		top[i] = virt_to_mfn(p2m_mid_missing_mfn);
> +		top[i] = virt_to_gfn(p2m_mid_missing_mfn);
>  }
>  
>  static void p2m_top_mfn_p_init(unsigned long **top)
> @@ -145,7 +145,7 @@ static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
>  	unsigned i;
>  
>  	for (i = 0; i < P2M_MID_PER_PAGE; i++)
> -		mid[i] = virt_to_mfn(leaf);
> +		mid[i] = virt_to_gfn(leaf);
>  }
>  
>  static void p2m_init(unsigned long *p2m)
> @@ -236,7 +236,7 @@ void __ref xen_build_mfn_list_list(void)
>  		if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
>  			BUG_ON(mididx);
>  			BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
> -			p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
> +			p2m_top_mfn[topidx] = virt_to_gfn(p2m_mid_missing_mfn);
>  			pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
>  			continue;
>  		}
> @@ -248,7 +248,7 @@ void __ref xen_build_mfn_list_list(void)
>  			p2m_top_mfn_p[topidx] = mid_mfn_p;
>  		}
>  
> -		p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
> +		p2m_top_mfn[topidx] = virt_to_gfn(mid_mfn_p);
>  		mid_mfn_p[mididx] = mfn;
>  	}
>  }
> @@ -261,7 +261,7 @@ void xen_setup_mfn_list_list(void)
>  	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
>  
>  	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
> -		virt_to_mfn(p2m_top_mfn);
> +		virt_to_gfn(p2m_top_mfn);
>  	HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
>  }
>  
> @@ -531,7 +531,7 @@ static bool alloc_p2m(unsigned long pfn)
>  		top_mfn_p = &p2m_top_mfn[topidx];
>  		mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
>  
> -		BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
> +		BUG_ON(virt_to_gfn(mid_mfn) != *top_mfn_p);
>  
>  		if (mid_mfn == p2m_mid_missing_mfn) {
>  			/* Separately check the mid mfn level */
> @@ -545,12 +545,12 @@ static bool alloc_p2m(unsigned long pfn)
>  
>  			p2m_mid_mfn_init(mid_mfn, p2m_missing);
>  
> -			missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
> -			mid_mfn_mfn = virt_to_mfn(mid_mfn);
> +			missing_mfn = virt_to_gfn(p2m_mid_missing_mfn);
> +			mid_mfn_mfn = virt_to_gfn(mid_mfn);
>  			old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
>  			if (old_mfn != missing_mfn) {
>  				free_p2m_page(mid_mfn);
> -				mid_mfn = mfn_to_virt(old_mfn);
> +				mid_mfn = gfn_to_virt(old_mfn);
>  			} else {
>  				p2m_top_mfn_p[topidx] = mid_mfn;
>  			}
> @@ -580,7 +580,7 @@ static bool alloc_p2m(unsigned long pfn)
>  			set_pte(ptep,
>  				pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
>  			if (mid_mfn)
> -				mid_mfn[mididx] = virt_to_mfn(p2m);
> +				mid_mfn[mididx] = virt_to_gfn(p2m);
>  			p2m = NULL;
>  		}
>  
> @@ -682,7 +682,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
>  			continue;
>  
>  		if (map_ops[i].flags & GNTMAP_contains_pte) {
> -			pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
> +			pte = (pte_t *)(gfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
>  				(map_ops[i].host_addr & ~PAGE_MASK));
>  			mfn = pte_mfn(*pte);
>  		} else {
> @@ -690,7 +690,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
>  		}
>  		pfn = page_to_pfn(pages[i]);
>  
> -		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
> +		WARN(pfn_to_gfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
>  
>  		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
>  			ret = -ENOMEM;
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 55f388e..4c2e91d 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -231,10 +231,10 @@ static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
>  	/* Release pages first. */
>  	end = min(end_pfn, nr_pages);
>  	for (pfn = start_pfn; pfn < end; pfn++) {
> -		unsigned long mfn = pfn_to_mfn(pfn);
> +		unsigned long mfn = pfn_to_gfn(pfn);
>  
>  		/* Make sure pfn exists to start with */
> -		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
> +		if (mfn == INVALID_P2M_ENTRY || gfn_to_pfn(mfn) != pfn)
>  			continue;
>  
>  		ret = xen_free_mfn(mfn);
> @@ -313,7 +313,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
>  
>  	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
>  
> -	mfn_save = virt_to_mfn(buf);
> +	mfn_save = virt_to_gfn(buf);
>  
>  	for (ident_pfn_iter = start_pfn, remap_pfn_iter = remap_pfn;
>  	     ident_pfn_iter < ident_end_pfn;
> @@ -321,7 +321,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
>  		chunk = (left < REMAP_SIZE) ? left : REMAP_SIZE;
>  
>  		/* Map first pfn to xen_remap_buf */
> -		mfn = pfn_to_mfn(ident_pfn_iter);
> +		mfn = pfn_to_gfn(ident_pfn_iter);
>  		set_pte_mfn(buf, mfn, PAGE_KERNEL);
>  
>  		/* Save mapping information in page */
> @@ -329,7 +329,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
>  		xen_remap_buf.target_pfn = remap_pfn_iter;
>  		xen_remap_buf.size = chunk;
>  		for (i = 0; i < chunk; i++)
> -			xen_remap_buf.mfns[i] = pfn_to_mfn(ident_pfn_iter + i);
> +			xen_remap_buf.mfns[i] = pfn_to_gfn(ident_pfn_iter + i);
>  
>  		/* Put remap buf into list. */
>  		xen_remap_mfn = mfn;
> @@ -473,7 +473,7 @@ void __init xen_remap_memory(void)
>  	unsigned long pfn_s = ~0UL;
>  	unsigned long len = 0;
>  
> -	mfn_save = virt_to_mfn(buf);
> +	mfn_save = virt_to_gfn(buf);
>  
>  	while (xen_remap_mfn != INVALID_P2M_ENTRY) {
>  		/* Map the remap information */
> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
> index 8648438..680f281 100644
> --- a/arch/x86/xen/smp.c
> +++ b/arch/x86/xen/smp.c
> @@ -395,7 +395,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
>  
>  		gdt_mfn = arbitrary_virt_to_mfn(gdt);
>  		make_lowmem_page_readonly(gdt);
> -		make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
> +		make_lowmem_page_readonly(gfn_to_virt(gdt_mfn));
>  
>  		ctxt->gdt_frames[0] = gdt_mfn;
>  		ctxt->gdt_ents      = GDT_ENTRIES;
> @@ -429,7 +429,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
>  	}
>  #endif
>  	ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
> -	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
> +	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
>  	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
>  		BUG();
>  
> diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
> index 53b4c08..60624e7 100644
> --- a/arch/x86/xen/suspend.c
> +++ b/arch/x86/xen/suspend.c
> @@ -16,9 +16,9 @@ static void xen_pv_pre_suspend(void)
>  {
>  	xen_mm_pin_all();
>  
> -	xen_start_info->store_mfn = mfn_to_pfn(xen_start_info->store_mfn);
> +	xen_start_info->store_mfn = gfn_to_pfn(xen_start_info->store_mfn);
>  	xen_start_info->console.domU.mfn =
> -		mfn_to_pfn(xen_start_info->console.domU.mfn);
> +		gfn_to_pfn(xen_start_info->console.domU.mfn);
>  
>  	BUG_ON(!irqs_disabled());
>  
> @@ -51,9 +51,9 @@ static void xen_pv_post_suspend(int suspend_cancelled)
>  
>  	if (suspend_cancelled) {
>  		xen_start_info->store_mfn =
> -			pfn_to_mfn(xen_start_info->store_mfn);
> +			pfn_to_gfn(xen_start_info->store_mfn);
>  		xen_start_info->console.domU.mfn =
> -			pfn_to_mfn(xen_start_info->console.domU.mfn);
> +			pfn_to_gfn(xen_start_info->console.domU.mfn);
>  	} else {
>  #ifdef CONFIG_SMP
>  		BUG_ON(xen_cpu_initialized_map == NULL);
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 6d89ed3..2e541a4 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -247,7 +247,7 @@ static struct grant *get_grant(grant_ref_t *gref_head,
>                                 struct blkfront_info *info)
>  {
>  	struct grant *gnt_list_entry;
> -	unsigned long buffer_mfn;
> +	unsigned long buffer_gfn;
>  
>  	BUG_ON(list_empty(&info->grants));
>  	gnt_list_entry = list_first_entry(&info->grants, struct grant,
> @@ -266,10 +266,10 @@ static struct grant *get_grant(grant_ref_t *gref_head,
>  		BUG_ON(!pfn);
>  		gnt_list_entry->pfn = pfn;
>  	}
> -	buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
> +	buffer_gfn = pfn_to_gfn(gnt_list_entry->pfn);
>  	gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
>  	                                info->xbdev->otherend_id,
> -	                                buffer_mfn, 0);
> +	                                buffer_gfn, 0);
>  	return gnt_list_entry;
>  }
>  
> diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
> index 95599e4..23d0549 100644
> --- a/drivers/input/misc/xen-kbdfront.c
> +++ b/drivers/input/misc/xen-kbdfront.c
> @@ -232,7 +232,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev,
>  	struct xenbus_transaction xbt;
>  
>  	ret = gnttab_grant_foreign_access(dev->otherend_id,
> -	                                  virt_to_mfn(info->page), 0);
> +	                                  virt_to_gfn(info->page), 0);
>  	if (ret < 0)
>  		return ret;
>  	info->gref = ret;
> @@ -255,7 +255,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev,
>  		goto error_irqh;
>  	}
>  	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
> -			    virt_to_mfn(info->page));
> +			    virt_to_gfn(info->page));
>  	if (ret)
>  		goto error_xenbus;
>  	ret = xenbus_printf(xbt, dev->nodename, "page-gref", "%u", info->gref);
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index 7d50711..3b7b7c3 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -314,7 +314,7 @@ static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb
>  		} else {
>  			copy_gop->source.domid = DOMID_SELF;
>  			copy_gop->source.u.gmfn =
> -				virt_to_mfn(page_address(page));
> +				virt_to_gfn(page_address(page));
>  		}
>  		copy_gop->source.offset = offset;
>  
> @@ -1284,7 +1284,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
>  		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
>  
>  		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
> -			virt_to_mfn(skb->data);
> +			virt_to_gfn(skb->data);
>  		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
>  		queue->tx_copy_ops[*copy_ops].dest.offset =
>  			offset_in_page(skb->data);
> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
> index f948c46..5cdab73 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -291,7 +291,7 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
>  		struct sk_buff *skb;
>  		unsigned short id;
>  		grant_ref_t ref;
> -		unsigned long pfn;
> +		unsigned long gfn;
>  		struct xen_netif_rx_request *req;
>  
>  		skb = xennet_alloc_one_rx_buffer(queue);
> @@ -307,12 +307,12 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
>  		BUG_ON((signed short)ref < 0);
>  		queue->grant_rx_ref[id] = ref;
>  
> -		pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
> +		gfn = page_to_gfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
>  
>  		req = RING_GET_REQUEST(&queue->rx, req_prod);
>  		gnttab_grant_foreign_access_ref(ref,
>  						queue->info->xbdev->otherend_id,
> -						pfn_to_mfn(pfn),
> +						gfn,
>  						0);
>  
>  		req->id = id;
> @@ -431,7 +431,7 @@ static struct xen_netif_tx_request *xennet_make_one_txreq(
>  	BUG_ON((signed short)ref < 0);
>  
>  	gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
> -					page_to_mfn(page), GNTMAP_readonly);
> +					page_to_gfn(page), GNTMAP_readonly);
>  
>  	queue->tx_skbs[id].skb = skb;
>  	queue->grant_tx_page[id] = page;
> diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
> index fad22ca..cdf00d1 100644
> --- a/drivers/scsi/xen-scsifront.c
> +++ b/drivers/scsi/xen-scsifront.c
> @@ -377,7 +377,6 @@ static int map_data_for_request(struct vscsifrnt_info *info,
>  	unsigned int data_len = scsi_bufflen(sc);
>  	unsigned int data_grants = 0, seg_grants = 0;
>  	struct scatterlist *sg;
> -	unsigned long mfn;
>  	struct scsiif_request_segment *seg;
>  
>  	ring_req->nr_segments = 0;
> @@ -420,9 +419,8 @@ static int map_data_for_request(struct vscsifrnt_info *info,
>  			ref = gnttab_claim_grant_reference(&gref_head);
>  			BUG_ON(ref == -ENOSPC);
>  
> -			mfn = pfn_to_mfn(page_to_pfn(page));
>  			gnttab_grant_foreign_access_ref(ref,
> -				info->dev->otherend_id, mfn, 1);
> +				info->dev->otherend_id, page_to_gfn(page), 1);
>  			shadow->gref[ref_cnt] = ref;
>  			ring_req->seg[ref_cnt].gref   = ref;
>  			ring_req->seg[ref_cnt].offset = (uint16_t)off;
> @@ -454,9 +452,9 @@ static int map_data_for_request(struct vscsifrnt_info *info,
>  			ref = gnttab_claim_grant_reference(&gref_head);
>  			BUG_ON(ref == -ENOSPC);
>  
> -			mfn = pfn_to_mfn(page_to_pfn(page));
>  			gnttab_grant_foreign_access_ref(ref,
> -				info->dev->otherend_id, mfn, grant_ro);
> +				info->dev->otherend_id, page_to_gfn(page),
> +				grant_ro);
>  
>  			shadow->gref[ref_cnt] = ref;
>  			seg->gref   = ref;
> diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> index a9d837f..efe5124 100644
> --- a/drivers/tty/hvc/hvc_xen.c
> +++ b/drivers/tty/hvc/hvc_xen.c
> @@ -265,7 +265,8 @@ static int xen_pv_console_init(void)
>  		return 0;
>  	}
>  	info->evtchn = xen_start_info->console.domU.evtchn;
> -	info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
> +	/* GFN == MFN for PV guest */
> +	info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
>  	info->vtermno = HVC_COOKIE;
>  
>  	spin_lock(&xencons_lock);
> @@ -390,7 +391,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
>  	if (IS_ERR(info->hvc))
>  		return PTR_ERR(info->hvc);
>  	if (xen_pv_domain())
> -		mfn = virt_to_mfn(info->intf);
> +		mfn = virt_to_gfn(info->intf);
>  	else
>  		mfn = __pa(info->intf) >> PAGE_SHIFT;
>  	ret = gnttab_alloc_grant_references(1, &gref_head);
> diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
> index 09dc447..25e3cce 100644
> --- a/drivers/video/fbdev/xen-fbfront.c
> +++ b/drivers/video/fbdev/xen-fbfront.c
> @@ -539,7 +539,7 @@ static int xenfb_remove(struct xenbus_device *dev)
>  
>  static unsigned long vmalloc_to_mfn(void *address)
>  {
> -	return pfn_to_mfn(vmalloc_to_pfn(address));
> +	return pfn_to_gfn(vmalloc_to_pfn(address));
>  }
>  
>  static void xenfb_init_shared_page(struct xenfb_info *info,
> @@ -586,7 +586,7 @@ static int xenfb_connect_backend(struct xenbus_device *dev,
>  		goto unbind_irq;
>  	}
>  	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
> -			    virt_to_mfn(info->page));
> +			    virt_to_gfn(info->page));
>  	if (ret)
>  		goto error_xenbus;
>  	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index fd93369..9734649 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -441,7 +441,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
>  	/* Update direct mapping, invalidate P2M, and add to balloon. */
>  	for (i = 0; i < nr_pages; i++) {
>  		pfn = frame_list[i];
> -		frame_list[i] = pfn_to_mfn(pfn);
> +		frame_list[i] = pfn_to_gfn(pfn);
>  		page = pfn_to_page(pfn);
>  
>  #ifdef CONFIG_XEN_HAVE_PVMMU
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index 96093ae..95a4fdb 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -1692,7 +1692,7 @@ void __init xen_init_IRQ(void)
>  		struct physdev_pirq_eoi_gmfn eoi_gmfn;
>  
>  		pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
> -		eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
> +		eoi_gmfn.gmfn = virt_to_gfn(pirq_eoi_map);
>  		rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
>  		/* TODO: No PVH support for PIRQ EOI */
>  		if (rc != 0) {
> diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
> index ed673e1..1d4baf5 100644
> --- a/drivers/xen/events/events_fifo.c
> +++ b/drivers/xen/events/events_fifo.c
> @@ -111,7 +111,7 @@ static int init_control_block(int cpu,
>  	for (i = 0; i < EVTCHN_FIFO_MAX_QUEUES; i++)
>  		q->head[i] = 0;
>  
> -	init_control.control_gfn = virt_to_mfn(control_block);
> +	init_control.control_gfn = virt_to_gfn(control_block);
>  	init_control.offset      = 0;
>  	init_control.vcpu        = cpu;
>  
> @@ -167,7 +167,7 @@ static int evtchn_fifo_setup(struct irq_info *info)
>  		/* Mask all events in this page before adding it. */
>  		init_array_page(array_page);
>  
> -		expand_array.array_gfn = virt_to_mfn(array_page);
> +		expand_array.array_gfn = virt_to_gfn(array_page);
>  
>  		ret = HYPERVISOR_event_channel_op(EVTCHNOP_expand_array, &expand_array);
>  		if (ret < 0)
> diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
> index e53fe19..13e1458 100644
> --- a/drivers/xen/gntalloc.c
> +++ b/drivers/xen/gntalloc.c
> @@ -142,7 +142,8 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
>  
>  		/* Grant foreign access to the page. */
>  		rc = gnttab_grant_foreign_access(op->domid,
> -			pfn_to_mfn(page_to_pfn(gref->page)), readonly);
> +						 page_to_gfn(gref->page),
> +						 readonly);
>  		if (rc < 0)
>  			goto undo;
>  		gref_ids[i] = gref->gref_id = rc;
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index d10effe..e12bd36 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -80,7 +80,7 @@ static int xen_suspend(void *data)
>  	 * is resuming in a new domain.
>  	 */
>  	si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
> -                                           ? virt_to_mfn(xen_start_info)
> +                                           ? virt_to_gfn(xen_start_info)
>                                             : 0);
>  
>  	xen_arch_post_suspend(si->cancelled);
> diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
> index 239738f..28c97ff 100644
> --- a/drivers/xen/tmem.c
> +++ b/drivers/xen/tmem.c
> @@ -131,7 +131,7 @@ static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
>  static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
>  			     u32 index, unsigned long pfn)
>  {
> -	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
> +	unsigned long gmfn = pfn_to_gfn(pfn);
>  
>  	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
>  		gmfn, 0, 0, 0);
> @@ -140,7 +140,7 @@ static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
>  static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
>  			     u32 index, unsigned long pfn)
>  {
> -	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
> +	unsigned long gmfn = pfn_to_gfn(pfn);
>  
>  	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
>  		gmfn, 0, 0, 0);
> diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
> index 9ad3272..daa267a 100644
> --- a/drivers/xen/xenbus/xenbus_client.c
> +++ b/drivers/xen/xenbus/xenbus_client.c
> @@ -380,7 +380,7 @@ int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
>  
>  	for (i = 0; i < nr_pages; i++) {
>  		err = gnttab_grant_foreign_access(dev->otherend_id,
> -						  virt_to_mfn(vaddr), 0);
> +						  virt_to_gfn(vaddr), 0);
>  		if (err < 0) {
>  			xenbus_dev_fatal(dev, err,
>  					 "granting access to ring page");
> diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c
> index b17707e..ee6d9ef 100644
> --- a/drivers/xen/xenbus/xenbus_dev_backend.c
> +++ b/drivers/xen/xenbus/xenbus_dev_backend.c
> @@ -49,7 +49,7 @@ static long xenbus_alloc(domid_t domid)
>  		goto out_err;
>  
>  	gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
> -			virt_to_mfn(xen_store_interface), 0 /* writable */);
> +			virt_to_gfn(xen_store_interface), 0 /* writable */);
>  
>  	arg.dom = DOMID_SELF;
>  	arg.remote_dom = domid;
> diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
> index 4308fb3..31836897 100644
> --- a/drivers/xen/xenbus/xenbus_probe.c
> +++ b/drivers/xen/xenbus/xenbus_probe.c
> @@ -711,9 +711,7 @@ static int __init xenstored_local_init(void)
>  	if (!page)
>  		goto out_err;
>  
> -	xen_store_mfn = xen_start_info->store_mfn =
> -		pfn_to_mfn(virt_to_phys((void *)page) >>
> -			   PAGE_SHIFT);
> +	xen_store_mfn = xen_start_info->store_mfn = virt_to_gfn(page);
>  
>  	/* Next allocate a local port which xenstored can bind to */
>  	alloc_unbound.dom        = DOMID_SELF;
> @@ -787,12 +785,12 @@ static int __init xenbus_init(void)
>  		err = xenstored_local_init();
>  		if (err)
>  			goto out_error;
> -		xen_store_interface = mfn_to_virt(xen_store_mfn);
> +		xen_store_interface = gfn_to_virt(xen_store_mfn);
>  		break;
>  	case XS_PV:
>  		xen_store_evtchn = xen_start_info->store_evtchn;
>  		xen_store_mfn = xen_start_info->store_mfn;
> -		xen_store_interface = mfn_to_virt(xen_store_mfn);
> +		xen_store_interface = gfn_to_virt(xen_store_mfn);
>  		break;
>  	case XS_HVM:
>  		err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
> diff --git a/include/xen/page.h b/include/xen/page.h
> index c5ed20b..e7e1425 100644
> --- a/include/xen/page.h
> +++ b/include/xen/page.h
> @@ -3,9 +3,9 @@
>  
>  #include <asm/xen/page.h>
>  
> -static inline unsigned long page_to_mfn(struct page *page)
> +static inline unsigned long page_to_gfn(struct page *page)
>  {
> -	return pfn_to_mfn(page_to_pfn(page));
> +	return pfn_to_gfn(page_to_pfn(page));
>  }
>  
>  struct xen_memory_region {
> -- 
> 2.1.4
>