[PATCH V10 05/14] xen/pvh: balloon and grant changes.

[Konrad Rzeszutek Wilk]

From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>

For balloon changes we skip setting of local P2M as it's updated
in Xen. For grant, the shared grant frame is the PFN and not MFN,
hence its mapped via the same code path as HVM.

Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
[v1: Rebase on v3.7-rc3]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
CC: <stefano.stabellini@xxxxxxxxxxxxx>
Conflicts:
	drivers/xen/balloon.c
[v2: Rebase on v3.13-rc3 has lot of ARM changes.]
---
 drivers/xen/balloon.c     |   37 ++++++++++++++++++++-----------------
 drivers/xen/gntdev.c      |    3 ++-
 drivers/xen/grant-table.c |   25 ++++++++++++++++++++++---
 3 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 55ea73f..0e9875a 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -354,7 +354,9 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 
 #ifdef CONFIG_XEN_HAVE_PVMMU
 		/* Link back into the page tables if not highmem. */
-		if (xen_pv_domain() && !PageHighMem(page)) {
+		if (xen_pv_domain() && !PageHighMem(page) &&
+		    !xen_feature(XENFEAT_auto_translated_physmap)) {
+
 			int ret;
 			ret = HYPERVISOR_update_va_mapping(
 				(unsigned long)__va(pfn << PAGE_SHIFT),
@@ -411,28 +413,29 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 
 		scrub_page(page);
 
-		/*
-		 * Ballooned out frames are effectively replaced with
-		 * a scratch frame.  Ensure direct mappings and the
-		 * p2m are consistent.
-		 */
-		scratch_page = get_balloon_scratch_page();
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			unsigned long p;
+
+			/*
+			 * Ballooned out frames are effectively replaced with
+			 * a scratch frame.  Ensure direct mappings and the
+			 * p2m are consistent.
+			 */
+			scratch_page = get_balloon_scratch_page();
 #ifdef CONFIG_XEN_HAVE_PVMMU
-		if (xen_pv_domain() && !PageHighMem(page)) {
-			ret = HYPERVISOR_update_va_mapping(
-				(unsigned long)__va(pfn << PAGE_SHIFT),
-				pfn_pte(page_to_pfn(scratch_page),
+			if (xen_pv_domain() && !PageHighMem(page)) {
+				ret = HYPERVISOR_update_va_mapping(
+					(unsigned long)__va(pfn << PAGE_SHIFT),
+					pfn_pte(page_to_pfn(scratch_page),
 					PAGE_KERNEL_RO), 0);
-			BUG_ON(ret);
-		}
+				BUG_ON(ret);
+			}
 #endif
-		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-			unsigned long p;
 			p = page_to_pfn(scratch_page);
 			__set_phys_to_machine(pfn, pfn_to_mfn(p));
-		}
-		put_balloon_scratch_page();
 
+			put_balloon_scratch_page();
+		}
 		balloon_append(pfn_to_page(pfn));
 	}
 
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index e41c79c..c1ae3ce 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -846,7 +846,8 @@ static int __init gntdev_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
-	use_ptemod = xen_pv_domain();
+	use_ptemod = xen_pv_domain() &&
+		     !xen_feature(XENFEAT_auto_translated_physmap);
 
 	err = misc_register(&gntdev_miscdev);
 	if (err != 0) {
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 0283871..1fcf75b 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -1056,14 +1056,20 @@ static void gnttab_unmap_frames_v2(void)
 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 {
 	struct gnttab_setup_table setup;
+	unsigned long start_gpfn;
 	xen_pfn_t *frames;
 	unsigned int nr_gframes = end_idx + 1;
 	int rc;
 
-	if (xen_hvm_domain()) {
+	if (xen_hvm_domain() || xen_feature(XENFEAT_auto_translated_physmap)) {
 		struct xen_add_to_physmap xatp;
 		unsigned int i = end_idx;
 		rc = 0;
+
+		if (xen_hvm_domain())
+			start_gpfn = xen_hvm_resume_frames >> PAGE_SHIFT;
+		else
+			start_gpfn = virt_to_pfn(gnttab_shared.addr);
 		/*
 		 * Loop backwards, so that the first hypercall has the largest
 		 * index, ensuring that the table will grow only once.
@@ -1072,7 +1078,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 			xatp.domid = DOMID_SELF;
 			xatp.idx = i;
 			xatp.space = XENMAPSPACE_grant_table;
-			xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
+			xatp.gpfn = start_gpfn + i;
 			rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
 			if (rc != 0) {
 				pr_warn("grant table add_to_physmap failed, err=%d\n",
@@ -1135,7 +1141,7 @@ static void gnttab_request_version(void)
 	int rc;
 	struct gnttab_set_version gsv;
 
-	if (xen_hvm_domain())
+	if (xen_hvm_domain() || xen_feature(XENFEAT_auto_translated_physmap))
 		gsv.version = 1;
 	else
 		gsv.version = 2;
@@ -1164,11 +1170,24 @@ static void gnttab_request_version(void)
 static int gnttab_setup(void)
 {
 	unsigned int max_nr_gframes;
+	char *kmsg = "Failed to kmalloc pages for pv in hvm grant frames\n";
 
 	max_nr_gframes = gnttab_max_grant_frames();
 	if (max_nr_gframes < nr_grant_frames)
 		return -ENOSYS;
 
+	/* PVH note: xen will free existing kmalloc'd mfn in
+	 * XENMEM_add_to_physmap. TBD/FIXME: use xen ballooning instead of
+	 * kmalloc(). */
+	if (xen_pv_domain() && xen_feature(XENFEAT_auto_translated_physmap) &&
+	    !gnttab_shared.addr) {
+		gnttab_shared.addr =
+			kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
+		if (!gnttab_shared.addr) {
+			pr_warn("%s", kmsg);
+			return -ENOMEM;
+		}
+	}
 	if (xen_pv_domain())
 		return gnttab_map(0, nr_grant_frames - 1);
 
-- 
1.7.7.6

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