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authorDavid Gibson <david@gibson.dropbear.id.au>2012-08-06 18:44:45 +0000
committerAlexander Graf <agraf@suse.de>2012-08-15 19:43:14 +0200
commit78e8fde26c032931ca2ae13bfc7c59e38afd17ee (patch)
tree88ea082231dfe0bcf791b67aa50edf906583f248 /target-ppc
parent4d5c29ca455ed6adb1fb9f8394e4d7badfd0c532 (diff)
ppc: Fix bug in handling of PAPR hypercall exits
Currently for powerpc, kvm_arch_handle_exit() always returns 1, meaning that its caller - kvm_cpu_exec() - will always exit immediately afterwards to the loop in qemu_kvm_cpu_thread_fn(). There's no need to do this. Once we've handled the hypercall there's no reason we can't go straight around and KVM_RUN again, which is what ret = 0 will signal. The only exception might be for hypercalls which affect the state of cpu_can_run(), however the only one that might do this is H_CEDE and for kvm that is always handled in the kernel, not qemu. Furtherm setting ret = 0 means that when exit_requested is set from a hypercall, we will enter KVM_RUN once more with a signal which lets the the kernel do its internal logic to complete the hypercall with out actually executing any more guest code. This is important if our hypercall also triggered a reset, which previously would re-initialize everything without completing the hypercall. This caused the kernel to get confused because it thought the guest was still in the middle of a hypercall when it has actually been reset. This patch therefore changes to ret = 0, which is both a bugfix and a small optimization. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'target-ppc')
-rw-r--r--target-ppc/kvm.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 829e180f8b..a31d278a5f 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -766,7 +766,7 @@ int kvm_arch_handle_exit(CPUPPCState *env, struct kvm_run *run)
dprintf("handle PAPR hypercall\n");
run->papr_hcall.ret = spapr_hypercall(env, run->papr_hcall.nr,
run->papr_hcall.args);
- ret = 1;
+ ret = 0;
break;
#endif
default: