[Qemu-devel] [PATCH v2] vl.c: prohibit simultaneous use of -icount with kvm or xen

[Max Filippov <jcmvbkbc@gmail.com>]

With -icount, The vm_clock is updated with help from TCG (it counts
instructions at 2^ICOUNT ns/instructions). With KVM, the instruction
count is not available so KVM cannot provide this help.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
v1 -> v2 changes:
- cover both kvm and xen;
- add explanation text.
---
 vl.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/vl.c b/vl.c
index f169aac..bb601e2 100644
--- a/vl.c
+++ b/vl.c
@@ -3226,6 +3226,11 @@ int main(int argc, char **argv, char **envp)
         fprintf(stderr, "could not initialize alarm timer\n");
         exit(1);
     }
+
+    if (icount_option && (kvm_enabled() || xen_enabled())) {
+        fprintf(stderr, "-icount is not allowed with kvm or xen\n");
+        exit(1);
+    }
     configure_icount(icount_option);
 
     if (net_init_clients() < 0) {
-- 
1.7.2.5