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authorthomas knych <thomaswk@google.com>2014-01-09 13:14:23 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2014-01-15 12:58:41 +0100
commit94ccff133820552a859c0fb95e33a539e0b90a75 (patch)
tree0fbf9538748867da53e5b72e6235f94784c51c0c /kvm-all.c
parent2ba82852894c762299b7d05e9a2be184116b80f0 (diff)
downloadqemu-94ccff133820552a859c0fb95e33a539e0b90a75.tar.gz
KVM: Retry KVM_CREATE_VM on EINTR
Upstreaming this change from Android (https://android-review.googlesource.com/54211). On heavily loaded machines with many VM instances we see KVM_CREATE_VM failing with EINTR on this path: kvm_dev_ioctl_create_vm -> kvm_create_vm -> kvm_init_mmu_notifier -> mmu_notifier_register -> do_mmu_notifier_register -> mm_take_all_locks which checks if any signals have been raised while it was attaining locks and returns EINTR. Retrying the system call greatly improves reliability. Cc: qemu-stable@nongnu.org Signed-off-by: thomas knych <thomaswk@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'kvm-all.c')
-rw-r--r--kvm-all.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kvm-all.c b/kvm-all.c
index 393775459d..6df2ee1635 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1442,16 +1442,22 @@ int kvm_init(void)
nc++;
}
- s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0);
- if (s->vmfd < 0) {
+ do {
+ ret = kvm_ioctl(s, KVM_CREATE_VM, 0);
+ } while (ret == -EINTR);
+
+ if (ret < 0) {
+ fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -s->vmfd,
+ strerror(-ret));
+
#ifdef TARGET_S390X
fprintf(stderr, "Please add the 'switch_amode' kernel parameter to "
"your host kernel command line\n");
#endif
- ret = s->vmfd;
goto err;
}
+ s->vmfd = ret;
missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);
if (!missing_cap) {
missing_cap =