[Qemu-devel] [PATCH v3 for 1.6 6/8] exec: Clean up unnecessary S390 ifdeffery

[Markus Armbruster <armbru@redhat.com>]

Another issue missed in commit fdec991 is -mem-path: it needs to be
rejected only for old S390 KVM, not for any S390.  Not that I
personally care, but the ifdeffery in qemu_ram_alloc_from_ptr() annoys
me.

Note that this doesn't actually make -mem-path work, as the kernel
doesn't (yet?)  support large pages in the host for KVM guests.  Clean
it up anyway.

Thanks to Christian Borntraeger for pointing out the S390 kernel
limitations.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 exec.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/exec.c b/exec.c
index dea4b1a..231d04e 100644
--- a/exec.c
+++ b/exec.c
@@ -904,7 +904,7 @@ void qemu_mutex_unlock_ramlist(void)
     qemu_mutex_unlock(&ram_list.mutex);
 }
 
-#if defined(__linux__) && !defined(TARGET_S390X)
+#ifdef __linux__
 
 #include <sys/vfs.h>
 
@@ -1007,6 +1007,14 @@ static void *file_ram_alloc(RAMBlock *block,
     block->fd = fd;
     return area;
 }
+#else
+static void *file_ram_alloc(RAMBlock *block,
+                            ram_addr_t memory,
+                            const char *path)
+{
+    fprintf(stderr, "-mem-path not supported on this host\n");
+    exit(1);
+}
 #endif
 
 static ram_addr_t find_ram_offset(ram_addr_t size)
@@ -1140,12 +1148,17 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
         xen_ram_alloc(new_block->offset, size, mr);
     } else {
         if (mem_path) {
-#if defined (__linux__) && !defined(TARGET_S390X)
+            if (phys_mem_alloc != qemu_anon_ram_alloc) {
+                /*
+                 * file_ram_alloc() needs to allocate just like
+                 * phys_mem_alloc, but we haven't bothered to provide
+                 * a hook there.
+                 */
+                fprintf(stderr,
+                        "-mem-path not supported with this accelerator\n");
+                exit(1);
+            }
             new_block->host = file_ram_alloc(new_block, size, mem_path);
-#else
-            fprintf(stderr, "-mem-path option unsupported\n");
-            exit(1);
-#endif
         }
         if (!new_block->host) {
             new_block->host = phys_mem_alloc(size);
-- 
1.7.11.7