[Qemu-devel] [PATCH v2] kvm: Fix enable_cap helpers on older gcc

[Alexander Graf <agraf@suse.de>]

Commit 40f1ee27aa1 introduced handy helpers for enable_cap calls on
vcpu and vm level. Unfortunately some older gcc versions (4.7.1, 4.6)
seem to choke on signedness detection in inline created variables:

target-ppc/kvm.c: In function 'kvmppc_booke_watchdog_enable':
target-ppc/kvm.c:1302:21: error: comparison of unsigned expression < 0 is always false [-Werror=type-limits]
target-ppc/kvm.c: In function 'kvmppc_set_papr':
target-ppc/kvm.c:1504:21: error: comparison of unsigned expression < 0 is always false [-Werror=type-limits]

However - thanks to Thomas Huth for the suggestion - we can just cast the
offending potentially 0 value to a signed type, making the comparison signed.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - only do cast, leaving readability intact

---
 include/sysemu/kvm.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 192fe89..76c39cc 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -302,7 +302,7 @@ int kvm_check_extension(KVMState *s, unsigned int extension);
         };                                                           \
         uint64_t args_tmp[] = { __VA_ARGS__ };                       \
         int i;                                                       \
-        for (i = 0; i < ARRAY_SIZE(args_tmp) &&                      \
+        for (i = 0; i < (int)ARRAY_SIZE(args_tmp) &&                 \
                      i < ARRAY_SIZE(cap.args); i++) {                \
             cap.args[i] = args_tmp[i];                               \
         }                                                            \
@@ -317,7 +317,7 @@ int kvm_check_extension(KVMState *s, unsigned int extension);
         };                                                           \
         uint64_t args_tmp[] = { __VA_ARGS__ };                       \
         int i;                                                       \
-        for (i = 0; i < ARRAY_SIZE(args_tmp) &&                      \
+        for (i = 0; i < (int)ARRAY_SIZE(args_tmp) &&                 \
                      i < ARRAY_SIZE(cap.args); i++) {                \
             cap.args[i] = args_tmp[i];                               \
         }                                                            \
-- 
1.8.1.4