On 09/09/2009 05:28 AM, Huang Ying wrote:
UCR (uncorrected recovery) MCE is supported in recent Intel CPUs,
where some hardware error such as some memory error can be reported
without PCC (processor context corrupted). To recover from such MCE,
the corresponding memory will be unmapped, and all processes accessing
the memory will be killed via SIGBUS.
For KVM, if QEMU/KVM is killed, all guest processes will be killed
too. So we relay SIGBUS from host OS to guest system via a UCR MCE
injection. Then guest OS can isolate corresponding memory and kill
necessary guest processes only. SIGBUS sent to main thread (not VCPU
threads) will be broadcast to all VCPU threads as UCR MCE.
v2:
- Use qemu_ram_addr_from_host instead of self made one to covert from
host address to guest RAM address. Thanks Anthony Liguori.
Patch looks good, but can you clarify the following:
@@ -1877,12 +1995,20 @@ void kvm_hpet_enable_kpit(void)
int kvm_init_ap(void)
{
+ struct sigaction action;
+
#ifdef TARGET_I386
kvm_tpr_opt_setup();
#endif
qemu_add_vm_change_state_handler(kvm_vm_state_change_handler, NULL);
signal(SIG_IPI, sig_ipi_handler);
+
+ memset(&action, 0, sizeof(action));
+ action.sa_flags = SA_SIGINFO;
+ action.sa_sigaction = (void (*)(int, siginfo_t*, void*))sigbus_handler;
+ sigaction(SIGBUS,&action, NULL);
+ prctl(PR_MCE_KILL, 1, 1);
return 0;
}
Why do we need a SIGBUS handler? kvm vcpu threads will block and
dequeue a SIGBUG in guest mode, so the handler will never be called, and
we can't really handle SIGBUS in user mode.
(also, I if we can't handle guest-mode SIGBUS I think it would be nice
to raise it again so the process terminates due to the SIGBUS).
--
error compiling committee.c: too many arguments to function
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