On 09/21/2011 01:48 PM, Nadav Har'El wrote:
This patch solves two outstanding nested-VMX issues:
<snip>
Sorry, I missed an important point on the first review.
--- .before/arch/x86/kvm/vmx.c 2011-09-21 13:45:59.000000000 +0300
+++ .after/arch/x86/kvm/vmx.c 2011-09-21 13:45:59.000000000 +0300
@@ -3858,12 +3858,17 @@ static bool nested_exit_on_intr(struct k
static void enable_irq_window(struct kvm_vcpu *vcpu)
{
u32 cpu_based_vm_exec_control;
- if (is_guest_mode(vcpu)&& nested_exit_on_intr(vcpu))
- /* We can get here when nested_run_pending caused
- * vmx_interrupt_allowed() to return false. In this case, do
- * nothing - the interrupt will be injected later.
+ if (is_guest_mode(vcpu)&& nested_exit_on_intr(vcpu)) {
+ /*
+ * We get here if vmx_interrupt_allowed() returned 0 because
+ * we must enter L2 now, so we can't inject to L1 now. If we
+ * just do nothing, L2 will later exit and we can inject the
+ * IRQ to L1 then. But to make L2 exit more promptly, we send
+ * a self-IPI, causing L2 to exit right after entry.
*/
+ smp_send_reschedule(vcpu->cpu);
return;
+ }
->enable_irq_window() is called with interrupts enabled, so the self-IPI
will be dispatched immediately and be lost.
The way to handle it is to kvm_make_request(KVM_REQ_IMMEDIATE_EXIT)
here, and to add code to vcpu_enter_guest() to sample this into a local
variable, and, after disabling interrupts, do the self-IPI.
A unit test would have caught this...
--
error compiling committee.c: too many arguments to function
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