[PATCH v2 0/8] Use correctly the Xen memory terminologies in Linux

[PATCH v2 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/xen/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.

Major changes in v2:
    - Use bfn rather than dfn for the DMA address
    - Re-introduced pfn_to_mfn for PV guests only
    - Typoes

For all the changes see in each patch.

This series is based on linus's branch. A branch with all the patches
can be found here:
    git://xenbits.xen.org/people/julieng/linux-arm.git branch page-renaming-v2

It was been boot tested on ARM64 and only built for x86 and ARM32.
I would be happy if someone can give a try on x86 as I don't have a x86
box setup with Xen.

Sincerely yours,

[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=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         | 37 +++++++++++++++++++++------
 arch/x86/xen/mmu.c                      | 32 ++++++++++++------------
 arch/x86/xen/smp.c                      |  2 +-
 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 ++++----
 29 files changed, 183 insertions(+), 170 deletions(-)

-- 
2.1.4

[PATCH v2 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 resulted in some misimplementation of helpers on ARM and
confused developers about 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 to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn but exclusively for PV (a BUG_ON has been added
to ensure this). No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.

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.

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

---
    Note that I've re-introduced mfn_to_pfn & co only for x86 PV code.
    The helpers contain a BUG_ON to ensure that it's never called for
    auto-translated guests. I did as best as my can to determine whether
    mfn or gfn helpers should be used. Although, I haven't tried to boot
    it.

    It may be possible to do further cleanup in the mmu.c where I found
    some check to auto-translated. I'm not sure why given that the pvmmu
    callback are only used for non-auto translated guest.

    Finally, given those changes, I didn't retain the Reviewed-by/Acked-by.

    Changes in v2:
        - Give directly the URL to the commit rather than the commit ID
        - xenstored_local_init: keep the cast to void *
        - Typoes
        - Keep pfn_to_mfn for x86 and PV-only. The *mfn* helpers are
        used in arch/x86/xen for enlighten.c, mmu.c, p2m.c, setup.c,
        smp.c and mm.c
---
 arch/arm/include/asm/xen/page.h         | 13 +++++++------
 arch/x86/include/asm/xen/page.h         | 33 ++++++++++++++++++++++++++-------
 arch/x86/xen/smp.c                      |  2 +-
 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 ++--
 20 files changed, 69 insertions(+), 51 deletions(-)

diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 087d86e..51e5bf1 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 <-> BUS conversion */
@@ -65,9 +66,9 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn)
 
 #define bfn_to_local_pfn(bfn)	bfn_to_pfn(bfn)
 
-/* 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. But ARM guests are always 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 8ba04b8..c2da42f 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -103,8 +103,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn)
 {
 	unsigned long mfn;
 
-	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return pfn;
+	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
 
 	mfn = __pfn_to_mfn(pfn);
 
@@ -149,8 +148,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
 {
 	unsigned long pfn;
 
-	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return mfn;
+	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
 
 	pfn = mfn_to_pfn_no_overrides(mfn);
 	if (__pfn_to_mfn(pfn) != mfn)
@@ -178,9 +176,26 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine)
 	return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
 }
 
+/* Pseudo-physical <-> Guest conversion */
+static inline unsigned long pfn_to_gfn(unsigned long pfn)
+{
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return pfn;
+	else
+		return pfn_to_mfn(pfn);
+}
+
+static inline unsigned long gfn_to_pfn(unsigned long gfn)
+{
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return gfn;
+	else
+		return mfn_to_pfn(gfn);
+}
+
 /* Pseudo-physical <-> Bus conversion */
-#define pfn_to_bfn(pfn)		pfn_to_mfn(pfn)
-#define bfn_to_pfn(bfn)		mfn_to_pfn(bfn)
+#define pfn_to_bfn(pfn)		pfn_to_gfn(pfn)
+#define bfn_to_pfn(bfn)		gfn_to_pfn(bfn)
 
 /*
  * We detect special mappings in one of two ways:
@@ -217,9 +232,13 @@ static inline unsigned long bfn_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))
+#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
+
+/* VIRT <-> GUEST conversion */
+#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
+#define gfn_to_virt(g)		(__va(gfn_to_pfn(g) << PAGE_SHIFT))
 
 static inline unsigned long pte_mfn(pte_t pte)
 {
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 8648438..1e0931b 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -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/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 bf4a23c..5df28cd 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 1495ecc..10fd9c6 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1694,7 +1694,7 @@ 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 6df8aac..2e55e90 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..b3870f4 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((void *)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

[PATCH v2 7/8] hvc/xen: Further s/MFN/GFN clean-up

[Julien Grall]

HVM_PARAM_CONSOLE_PFN is used to retrieved the console PFN for HVM
guest. It returns a PFN (aka GFN) and not a MFN.

Furthermore, use directly virt_to_gfn for both PV and HVM domain rather
than doing a special case for each of the them.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linuxppc-dev@lists.ozlabs.org

---
    Changes in v2:
        - Add David's reviewed-by
---
 drivers/tty/hvc/hvc_xen.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index efe5124..10beb15 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -200,7 +200,7 @@ static int xen_hvm_console_init(void)
 {
 	int r;
 	uint64_t v = 0;
-	unsigned long mfn;
+	unsigned long gfn;
 	struct xencons_info *info;
 
 	if (!xen_hvm_domain())
@@ -217,7 +217,7 @@ static int xen_hvm_console_init(void)
 	}
 	/*
 	 * If the toolstack (or the hypervisor) hasn't set these values, the
-	 * default value is 0. Even though mfn = 0 and evtchn = 0 are
+	 * default value is 0. Even though gfn = 0 and evtchn = 0 are
 	 * theoretically correct values, in practice they never are and they
 	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
 	 */
@@ -229,8 +229,8 @@ static int xen_hvm_console_init(void)
 	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
 	if (r < 0 || v == 0)
 		goto err;
-	mfn = v;
-	info->intf = xen_remap(mfn << PAGE_SHIFT, PAGE_SIZE);
+	gfn = v;
+	info->intf = xen_remap(gfn << PAGE_SHIFT, PAGE_SIZE);
 	if (info->intf == NULL)
 		goto err;
 	info->vtermno = HVC_COOKIE;
@@ -375,7 +375,6 @@ static int xencons_connect_backend(struct xenbus_device *dev,
 	int ret, evtchn, devid, ref, irq;
 	struct xenbus_transaction xbt;
 	grant_ref_t gref_head;
-	unsigned long mfn;
 
 	ret = xenbus_alloc_evtchn(dev, &evtchn);
 	if (ret)
@@ -390,10 +389,6 @@ static int xencons_connect_backend(struct xenbus_device *dev,
 			irq, &domU_hvc_ops, 256);
 	if (IS_ERR(info->hvc))
 		return PTR_ERR(info->hvc);
-	if (xen_pv_domain())
-		mfn = virt_to_gfn(info->intf);
-	else
-		mfn = __pa(info->intf) >> PAGE_SHIFT;
 	ret = gnttab_alloc_grant_references(1, &gref_head);
 	if (ret < 0)
 		return ret;
@@ -402,7 +397,7 @@ static int xencons_connect_backend(struct xenbus_device *dev,
 	if (ref < 0)
 		return ref;
 	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
-			mfn, 0);
+					virt_to_gfn(info->intf), 0);
 
  again:
 	ret = xenbus_transaction_start(&xbt);
-- 
2.1.4

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 08/04/2015 02:12 PM, Julien Grall wrote:
>   
>   /*
>    * We detect special mappings in one of two ways:
> @@ -217,9 +232,13 @@ static inline unsigned long bfn_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))
> +#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))

This looks like unnecessary change.


> 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));
>   }

Are you sure? This will return vmalloc_to_pfn(address)).


-boris

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Stefano Stabellini]

On Tue, 4 Aug 2015, Boris Ostrovsky wrote:
> On 08/04/2015 02:12 PM, Julien Grall wrote:
> >     /*
> >    * We detect special mappings in one of two ways:
> > @@ -217,9 +232,13 @@ static inline unsigned long bfn_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))
> > +#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
> 
> This looks like unnecessary change.
> 
> 
> > 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));
> >   }
> 
> Are you sure? This will return vmalloc_to_pfn(address)).

I think that is OK: there is no behavioural change here.

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Stefano Stabellini]

[-- Attachment #1: Type: text/plain, Size: 22710 bytes --]

On Tue, 4 Aug 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 resulted in some misimplementation of helpers on ARM and
> confused developers about 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 to mfn with
> gfn in any helpers used by PV drivers. The x86 code will still keep some
> reference of pfn_to_mfn but exclusively for PV (a BUG_ON has been added
> to ensure this). No changes as been made in the hypercall field, even
> though they may be invalid, in order to keep the same as the defintion
> in xen repo.
> 
> 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.
> 
> [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=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

Aside from the x86 bits:

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


>     Note that I've re-introduced mfn_to_pfn & co only for x86 PV code.
>     The helpers contain a BUG_ON to ensure that it's never called for
>     auto-translated guests. I did as best as my can to determine whether
>     mfn or gfn helpers should be used. Although, I haven't tried to boot
>     it.
> 
>     It may be possible to do further cleanup in the mmu.c where I found
>     some check to auto-translated. I'm not sure why given that the pvmmu
>     callback are only used for non-auto translated guest.
> 
>     Finally, given those changes, I didn't retain the Reviewed-by/Acked-by.
> 
>     Changes in v2:
>         - Give directly the URL to the commit rather than the commit ID
>         - xenstored_local_init: keep the cast to void *
>         - Typoes
>         - Keep pfn_to_mfn for x86 and PV-only. The *mfn* helpers are
>         used in arch/x86/xen for enlighten.c, mmu.c, p2m.c, setup.c,
>         smp.c and mm.c
> ---
>  arch/arm/include/asm/xen/page.h         | 13 +++++++------
>  arch/x86/include/asm/xen/page.h         | 33 ++++++++++++++++++++++++++-------
>  arch/x86/xen/smp.c                      |  2 +-
>  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 ++--
>  20 files changed, 69 insertions(+), 51 deletions(-)
> 
> diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
> index 087d86e..51e5bf1 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 <-> BUS conversion */
> @@ -65,9 +66,9 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn)
>  
>  #define bfn_to_local_pfn(bfn)	bfn_to_pfn(bfn)
>  
> -/* 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. But ARM guests are always 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 8ba04b8..c2da42f 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -103,8 +103,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn)
>  {
>  	unsigned long mfn;
>  
> -	if (xen_feature(XENFEAT_auto_translated_physmap))
> -		return pfn;
> +	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
>  
>  	mfn = __pfn_to_mfn(pfn);
>  
> @@ -149,8 +148,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
>  {
>  	unsigned long pfn;
>  
> -	if (xen_feature(XENFEAT_auto_translated_physmap))
> -		return mfn;
> +	BUG_ON(xen_feature(XENFEAT_auto_translated_physmap));
>  
>  	pfn = mfn_to_pfn_no_overrides(mfn);
>  	if (__pfn_to_mfn(pfn) != mfn)
> @@ -178,9 +176,26 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine)
>  	return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
>  }
>  
> +/* Pseudo-physical <-> Guest conversion */
> +static inline unsigned long pfn_to_gfn(unsigned long pfn)
> +{
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return pfn;
> +	else
> +		return pfn_to_mfn(pfn);
> +}
> +
> +static inline unsigned long gfn_to_pfn(unsigned long gfn)
> +{
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return gfn;
> +	else
> +		return mfn_to_pfn(gfn);
> +}
> +
>  /* Pseudo-physical <-> Bus conversion */
> -#define pfn_to_bfn(pfn)		pfn_to_mfn(pfn)
> -#define bfn_to_pfn(bfn)		mfn_to_pfn(bfn)
> +#define pfn_to_bfn(pfn)		pfn_to_gfn(pfn)
> +#define bfn_to_pfn(bfn)		gfn_to_pfn(bfn)
>  
>  /*
>   * We detect special mappings in one of two ways:
> @@ -217,9 +232,13 @@ static inline unsigned long bfn_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))
> +#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
> +
> +/* VIRT <-> GUEST conversion */
> +#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_pfn(v)))
> +#define gfn_to_virt(g)		(__va(gfn_to_pfn(g) << PAGE_SHIFT))
>  
>  static inline unsigned long pte_mfn(pte_t pte)
>  {
> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
> index 8648438..1e0931b 100644
> --- a/arch/x86/xen/smp.c
> +++ b/arch/x86/xen/smp.c
> @@ -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/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 bf4a23c..5df28cd 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 1495ecc..10fd9c6 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -1694,7 +1694,7 @@ 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 6df8aac..2e55e90 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..b3870f4 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((void *)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: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Hi Boris,

On 05/08/15 00:16, Boris Ostrovsky wrote:
> On 08/04/2015 02:12 PM, Julien Grall wrote:
>>     /*
>>    * We detect special mappings in one of two ways:
>> @@ -217,9 +232,13 @@ static inline unsigned long
>> bfn_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))
>> +#define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
> 
> This looks like unnecessary change.

Right, I made the mistake when I re-introduced virt_to_mfn in this
version. It was dropped in the previous one.

>> 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));
>>   }
> 
> Are you sure? This will return vmalloc_to_pfn(address)).

I guess you mean vmalloc_to_mfn will return vmalloc_to_pfn?

If so, it will be only the case on auto-translated case (because pfn ==
gfn). In the case of PV, the mfn will be returned.

Although, this function is misnamed. It's fixed in a follow-up patch
(see #6) because it's required more renaming than this function. I
didn't want to add such changes within this patch.

Regards,

-- 
Julien Grall

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 08/05/2015 06:51 AM, Julien Grall wrote:
>
>>> 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));
>>>    }
>> Are you sure? This will return vmalloc_to_pfn(address)).
> I guess you mean vmalloc_to_mfn will return vmalloc_to_pfn?
>
> If so, it will be only the case on auto-translated case (because pfn ==
> gfn). In the case of PV, the mfn will be returned.

How will mfn be returned on PV when pfn_to_gfn() is an identity function?

static inline unsigned long pfn_to_gfn(unsigned long pfn)
  {
      return pfn;
  }


-boris

>
> Although, this function is misnamed. It's fixed in a follow-up patch
> (see #6) because it's required more renaming than this function. I
> didn't want to add such changes within this patch.
>
> Regards,
>

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

On 05/08/15 13:19, Boris Ostrovsky wrote:
> On 08/05/2015 06:51 AM, Julien Grall wrote:
>>
>>>> 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));
>>>>    }
>>> Are you sure? This will return vmalloc_to_pfn(address)).
>> I guess you mean vmalloc_to_mfn will return vmalloc_to_pfn?
>>
>> If so, it will be only the case on auto-translated case (because pfn ==
>> gfn). In the case of PV, the mfn will be returned.
> 
> How will mfn be returned on PV when pfn_to_gfn() is an identity function?
> 
> static inline unsigned long pfn_to_gfn(unsigned long pfn)
>  {
>      return pfn;
>  }

The identity function is only for ARM guest which are always
auto-translated (arch/arm/include/asm/xen/page.h).

The x86 version contains a check if the guest is auto-translated or not
(arch/x86/include/asm/xen/page.):

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

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Boris Ostrovsky]

On 08/05/2015 08:33 AM, Julien Grall wrote:
> On 05/08/15 13:19, Boris Ostrovsky wrote:
>> On 08/05/2015 06:51 AM, Julien Grall wrote:
>>>>> 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));
>>>>>     }
>>>> Are you sure? This will return vmalloc_to_pfn(address)).
>>> I guess you mean vmalloc_to_mfn will return vmalloc_to_pfn?
>>>
>>> If so, it will be only the case on auto-translated case (because pfn ==
>>> gfn). In the case of PV, the mfn will be returned.
>> How will mfn be returned on PV when pfn_to_gfn() is an identity function?
>>
>> static inline unsigned long pfn_to_gfn(unsigned long pfn)
>>   {
>>       return pfn;
>>   }
> The identity function is only for ARM guest which are always
> auto-translated (arch/arm/include/asm/xen/page.h).
>
> The x86 version contains a check if the guest is auto-translated or not
> (arch/x86/include/asm/xen/page.):
>
> static inline unsigned long pfn_to_gfn(unsigned long pfn)
> {
>          if (xen_feature(XENFEAT_auto_translated_physmap))
>                  return pfn;
>          else
>                  return pfn_to_mfn(pfn);
> }

Of course --- I was looking at the top of the patch and didn't realize 
it was ARM changes. Sorry for the noise.

-boris

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Dmitry Torokhov]

On Wed, Aug 05, 2015 at 11:08:55AM +0100, Stefano Stabellini wrote:
> On Tue, 4 Aug 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 resulted in some misimplementation of helpers on ARM and
> > confused developers about 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 to mfn with
> > gfn in any helpers used by PV drivers. The x86 code will still keep some
> > reference of pfn_to_mfn but exclusively for PV (a BUG_ON has been added
> > to ensure this). No changes as been made in the hypercall field, even
> > though they may be invalid, in order to keep the same as the defintion
> > in xen repo.
> > 
> > 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.
> > 
> > [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=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
> 
> Aside from the x86 bits:
> 
> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Not really important, but just in case anyone waits for my ack on input
bits:

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Thanks.

-- 
Dmitry

Re: [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Wei Liu]

On Tue, Aug 04, 2015 at 07:12:48PM +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);

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

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

Hi,


On 04/08/15 19:12, Julien Grall wrote:
> 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));
>  }

I've just noticed that there is a function gfn_to_page used for KVM.

Maybe I should rename page_to_gfn to xen_page_to_gfn to avoid confusion
with KVM one?

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Stefano Stabellini]

On Thu, 6 Aug 2015, Julien Grall wrote:
> Hi,
> 
> 
> On 04/08/15 19:12, Julien Grall wrote:
> > 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));
> >  }
> 
> I've just noticed that there is a function gfn_to_page used for KVM.
> 
> Maybe I should rename page_to_gfn to xen_page_to_gfn to avoid confusion
> with KVM one?

Yeah, prepending xen would help to avoid namespace pollution.

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Julien Grall]

On 06/08/15 12:06, Stefano Stabellini wrote:
> On Thu, 6 Aug 2015, Julien Grall wrote:
>> Hi,
>>
>>
>> On 04/08/15 19:12, Julien Grall wrote:
>>> 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));
>>>  }
>>
>> I've just noticed that there is a function gfn_to_page used for KVM.
>>
>> Maybe I should rename page_to_gfn to xen_page_to_gfn to avoid confusion
>> with KVM one?
> 
> Yeah, prepending xen would help to avoid namespace pollution.

Will do. May I keep your Reviewed-by for this mechanical change?

Regards,

-- 
Julien Grall

Re: [Xen-devel] [PATCH v2 4/8] xen: Use the correctly the Xen memory terminologies

[Stefano Stabellini]

On Thu, 6 Aug 2015, Julien Grall wrote:
> On 06/08/15 12:06, Stefano Stabellini wrote:
> > On Thu, 6 Aug 2015, Julien Grall wrote:
> >> Hi,
> >>
> >>
> >> On 04/08/15 19:12, Julien Grall wrote:
> >>> 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));
> >>>  }
> >>
> >> I've just noticed that there is a function gfn_to_page used for KVM.
> >>
> >> Maybe I should rename page_to_gfn to xen_page_to_gfn to avoid confusion
> >> with KVM one?
> > 
> > Yeah, prepending xen would help to avoid namespace pollution.
> 
> Will do. May I keep your Reviewed-by for this mechanical change?

Yes