[Xen-devel] [PATCH] libxc: Introduce xc_domain_nr_gpfns as a cousin of xc_domain_maximum_gpfn.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

The commit a8f8a590e02d2d2b717257c0bd9a8b396103bdf4
"libxc: Check xc_domain_maximum_gpfn for negative return values"
introduced an regression in tools outside libxc (migrate v2)
which wanted the unfiltered GPFN value. Said commit added
a wrapper which added +1 if there were no errors.

To make it work pre-commit a8f8a59 we add an xc_domain_nr_gpfns
which will add +1 if there are no errors (and change all in-tree
callers to use it). The xc_domain_maximum_gpfn will return the
unfiltered GPFN value.

Suggested-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 tools/libxc/include/xenctrl.h |  2 ++
 tools/libxc/xc_core_arm.c     |  2 +-
 tools/libxc/xc_core_x86.c     |  6 +++---
 tools/libxc/xc_domain.c       | 12 +++++++++++-
 tools/libxc/xc_domain_save.c  |  2 +-
 5 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 4e9537e..552ace8 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1317,6 +1317,8 @@ int xc_domain_disable_migrate(xc_interface *xch, uint32_t 
domid);
 
 int xc_domain_maximum_gpfn(xc_interface *xch, domid_t domid, xen_pfn_t *gpfns);
 
+int xc_domain_nr_gpfns(xc_interface *xch, domid_t domid, xen_pfn_t *gpfns);
+
 int xc_domain_increase_reservation(xc_interface *xch,
                                    uint32_t domid,
                                    unsigned long nr_extents,
diff --git a/tools/libxc/xc_core_arm.c b/tools/libxc/xc_core_arm.c
index c3f5868..57d4715 100644
--- a/tools/libxc/xc_core_arm.c
+++ b/tools/libxc/xc_core_arm.c
@@ -45,7 +45,7 @@ xc_core_arch_memory_map_get(xc_interface *xch, struct 
xc_core_arch_context *unus
     xen_pfn_t p2m_size = 0;
     xc_core_memory_map_t *map;
 
-    if ( xc_domain_maximum_gpfn(xch, info->domid, &p2m_size) < 0 )
+    if ( xc_domain_nr_gpfns(xch, info->domid, &p2m_size) < 0 )
         return -1;
 
     map = malloc(sizeof(*map));
diff --git a/tools/libxc/xc_core_x86.c b/tools/libxc/xc_core_x86.c
index 4552e43..93ebcbb 100644
--- a/tools/libxc/xc_core_x86.c
+++ b/tools/libxc/xc_core_x86.c
@@ -50,7 +50,7 @@ xc_core_arch_memory_map_get(xc_interface *xch, struct 
xc_core_arch_context *unus
     xen_pfn_t p2m_size = 0;
     xc_core_memory_map_t *map;
 
-    if ( xc_domain_maximum_gpfn(xch, info->domid, &p2m_size) < 0 )
+    if ( xc_domain_nr_gpfns(xch, info->domid, &p2m_size) < 0 )
         return -1;
 
     map = malloc(sizeof(*map));
@@ -85,7 +85,7 @@ xc_core_arch_map_p2m_rw(xc_interface *xch, struct 
domain_info_context *dinfo, xc
     int err;
     int i;
 
-    if ( xc_domain_maximum_gpfn(xch, info->domid, &dinfo->p2m_size) < 0 )
+    if ( xc_domain_nr_gpfns(xch, info->domid, &dinfo->p2m_size) < 0 )
     {
         ERROR("Could not get maximum GPFN!");
         goto out;
@@ -212,7 +212,7 @@ int
 xc_core_arch_get_scratch_gpfn(xc_interface *xch, domid_t domid,
                               xen_pfn_t *gpfn)
 {
-    return xc_domain_maximum_gpfn(xch, domid, gpfn);
+    return xc_domain_nr_gpfns(xch, domid, gpfn);
 }
 
 /*
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index da88e08..dc62eff 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -795,12 +795,22 @@ int xc_domain_maximum_gpfn(xc_interface *xch, domid_t 
domid, xen_pfn_t *gpfns)
 
     if ( rc >= 0 )
     {
-        *gpfns = rc + 1;
+        *gpfns = rc;
         rc = 0;
     }
     return rc;
 }
 
+int xc_domain_nr_gpfns(xc_interface *xch, domid_t domid, xen_pfn_t *gpfns)
+{
+    int rc = xc_domain_maximum_gpfn(xch, domid, gpfns);
+
+    if ( rc >= 0 )
+        *gpfns += 1;
+
+    return rc;
+}
+
 int xc_domain_increase_reservation(xc_interface *xch,
                                    uint32_t domid,
                                    unsigned long nr_extents,
diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
index b611c07..cef6995 100644
--- a/tools/libxc/xc_domain_save.c
+++ b/tools/libxc/xc_domain_save.c
@@ -939,7 +939,7 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t 
dom, uint32_t max_iter
     }
 
     /* Get the size of the P2M table */
-    if ( xc_domain_maximum_gpfn(xch, dom, &dinfo->p2m_size) < 0 )
+    if ( xc_domain_nr_gpfns(xch, dom, &dinfo->p2m_size) < 0 )
     {
         ERROR("Could not get maximum GPFN!");
         goto out;
-- 
2.1.0


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