From: thomas knych <address@hidden>
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: address@hidden
Signed-off-by: thomas knych <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
kvm-all.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/kvm-all.c b/kvm-all.c
index 3937754..6df2ee1 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,