[Qemu-devel] [PATCH] s390x: remove direct reference to mem_path global form s90x code

[Igor Mammedov]

I plan to deprecate -mem-path option and replace it with memory-backend,
for that it's necessary to get rid of mem_path global variable.
Do it for s390x case, replacing it with alternative way to enable
1Mb hugepages capability.

Signed-off-by: Igor Mammedov <imamm...@redhat.com>
---
PS:
Original code nor the new one probably is not entirely correct when
huge pages are enabled in case where mixed initial RAM and memory
backends are used, backend's page size might not match initial RAM's
so I'm not sure if enabling 1MB cap is correct in this case on s390
(should it be the same for all RAM???).
With new approach 1Mb cap is not enabled if the smallest page size
is not 1Mb.
---
 target/s390x/kvm.c | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 2ebf26a..22e868a 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -285,33 +285,28 @@ void kvm_s390_crypto_reset(void)
     }
 }
 
-static int kvm_s390_configure_mempath_backing(KVMState *s)
+static int kvm_s390_configure_hugepage_backing(KVMState *s)
 {
-    size_t path_psize = qemu_mempath_getpagesize(mem_path);
+    size_t psize = qemu_getrampagesize();
 
-    if (path_psize == 4 * KiB) {
-        return 0;
-    }
-
-    if (!hpage_1m_allowed()) {
-        error_report("This QEMU machine does not support huge page "
-                     "mappings");
-        return -EINVAL;
-    }
+    if (psize == 1 * MiB) {
+        if (!hpage_1m_allowed()) {
+            error_report("This QEMU machine does not support huge page "
+                         "mappings");
+            return -EINVAL;
+        }
 
-    if (path_psize != 1 * MiB) {
+        if (kvm_vm_enable_cap(s, KVM_CAP_S390_HPAGE_1M, 0)) {
+            error_report("Memory backing with 1M pages was specified, "
+                         "but KVM does not support this memory backing");
+            return -EINVAL;
+        }
+        cap_hpage_1m = 1;
+    } else if (psize == 2 * GiB) {
         error_report("Memory backing with 2G pages was specified, "
                      "but KVM does not support this memory backing");
         return -EINVAL;
     }
-
-    if (kvm_vm_enable_cap(s, KVM_CAP_S390_HPAGE_1M, 0)) {
-        error_report("Memory backing with 1M pages was specified, "
-                     "but KVM does not support this memory backing");
-        return -EINVAL;
-    }
-
-    cap_hpage_1m = 1;
     return 0;
 }
 
@@ -319,7 +314,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
 {
     MachineClass *mc = MACHINE_GET_CLASS(ms);
 
-    if (mem_path && kvm_s390_configure_mempath_backing(s)) {
+    if (kvm_s390_configure_hugepage_backing(s)) {
         return -EINVAL;
     }
 
-- 
2.7.4