[Qemu-devel] [PATCH v1 4/6] xen: use errno instead of rc for xc_domain_add_to_physmap

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

In Xen 4.6 commit cd2f100f0f61b3f333d52d1737dd73f02daee592
"libxc: Fix do_memory_op to return negative value on errors"
made the libxc API less odd-ball: On errors, return value is
-1 and error code is in errno. On success the return value
is either 0 or an positive value.

Since we could be running with an old toolstack in which the
Exx value is in rc or the newer, we add an wrapper around
the xc_domain_add_to_physmap (called xen_xc_domain_add_to_physmap)
which will always return the EXX.

Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 include/hw/xen/xen_common.h | 22 ++++++++++++++++++++++
 xen-hvm.c                   |  4 ++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 38f29fb..fc66c3c 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -407,4 +407,26 @@ static inline int xen_set_ioreq_server_state(XenXC xc, domid_t dom,
 
 #endif
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 460
+static inline int xen_xc_domain_add_to_physmap(XenXC xch, uint32_t domid,
+                                               unsigned int space,
+                                               unsigned long idx,
+                                               xen_pfn_t gpfn)
+{
+    return xc_domain_add_to_physmap(xch, domid, space, idx, gpfn);
+}
+#else
+static inline int xen_xc_domain_add_to_physmap(XenXC xch, uint32_t domid,
+                                               unsigned int space,
+                                               unsigned long idx,
+                                               xen_pfn_t gpfn)
+{
+    /* In Xen 4.6 rc is -1 and errno contains the error value. */
+    int rc = xc_domain_add_to_physmap(xch, domid, space, idx, gpfn);
+    if (rc == -1)
+        return errno;
+    return rc;
+}
+#endif
+
 #endif /* QEMU_HW_XEN_COMMON_H */
diff --git a/xen-hvm.c b/xen-hvm.c
index 0408462..fae2d22 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -345,7 +345,7 @@ go_physmap:
         unsigned long idx = pfn + i;
         xen_pfn_t gpfn = start_gpfn + i;
 
-        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
+        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
         if (rc) {
             DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
                     PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
@@ -422,7 +422,7 @@ static int xen_remove_from_physmap(XenIOState *state,
         xen_pfn_t idx = start_addr + i;
         xen_pfn_t gpfn = phys_offset + i;
 
-        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
+        rc = xen_xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
         if (rc) {
             fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
                     PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
-- 
2.1.0