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| author | Avi Kivity <avi@redhat.com> | 2010-12-02 17:52:50 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-01-12 11:30:18 +0200 |
| commit | b7c4145ba2eb0717db0ddac1b5f7f48012189c53 (patch) | |
| tree | 9b259970f56451ecb0f5d84ecd81d67386f63224 | |
| parent | 4cc703100b1fd97c71804e2fa5c9c377c5b37dc5 (diff) | |
| download | linux-b7c4145ba2eb0717db0ddac1b5f7f48012189c53.tar.gz linux-b7c4145ba2eb0717db0ddac1b5f7f48012189c53.tar.bz2 linux-b7c4145ba2eb0717db0ddac1b5f7f48012189c53.zip | |
KVM: Don't spin on virt instruction faults during reboot
Since vmx blocks INIT signals, we disable virtualization extensions during
reboot. This leads to virtualization instructions faulting; we trap these
faults and spin while the reboot continues.
Unfortunately spinning on a non-preemptible kernel may block a task that
reboot depends on; this causes the reboot to hang.
Fix by skipping over the instruction and hoping for the best.
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 8 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 13 |
2 files changed, 10 insertions, 11 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 56e45a2ed2de..d968cc501799 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -786,14 +786,18 @@ enum { * reboot turns off virtualization while processes are running. * Trap the fault and ignore the instruction if that happens. */ -asmlinkage void kvm_handle_fault_on_reboot(void); +asmlinkage void kvm_spurious_fault(void); +extern bool kvm_rebooting; #define __kvm_handle_fault_on_reboot(insn) \ "666: " insn "\n\t" \ + "668: \n\t" \ ".pushsection .fixup, \"ax\" \n" \ "667: \n\t" \ + "cmpb $0, kvm_rebooting \n\t" \ + "jne 668b \n\t" \ __ASM_SIZE(push) " $666b \n\t" \ - "jmp kvm_handle_fault_on_reboot \n\t" \ + "call kvm_spurious_fault \n\t" \ ".popsection \n\t" \ ".pushsection __ex_table, \"a\" \n\t" \ _ASM_PTR " 666b, 667b \n\t" \ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ee99b77e4451..7f686251f711 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -90,7 +90,8 @@ static void hardware_disable_all(void); static void kvm_io_bus_destroy(struct kvm_io_bus *bus); -static bool kvm_rebooting; +bool kvm_rebooting; +EXPORT_SYMBOL_GPL(kvm_rebooting); static bool largepages_enabled = true; @@ -2171,18 +2172,12 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, } -asmlinkage void kvm_handle_fault_on_reboot(void) +asmlinkage void kvm_spurious_fault(void) { - if (kvm_rebooting) { - /* spin while reset goes on */ - local_irq_enable(); - while (true) - cpu_relax(); - } /* Fault while not rebooting. We want the trace. */ BUG(); } -EXPORT_SYMBOL_GPL(kvm_handle_fault_on_reboot); +EXPORT_SYMBOL_GPL(kvm_spurious_fault); static int kvm_reboot(struct notifier_block *notifier, unsigned long val, void *v) |