On 04/14/2030 12:05 PM, Zhang, Yanmin wrote:
Here is the new patch of V3 against tip/master of April 13th
if anyone wants to try it.
Thanks for persisting despite the flames.
Can you please separate arch/x86/kvm part of the patch? That will make
for easier reviewing, and will need to go through separate trees.
Sheng, did you make any progress with the NMI injection issue?
+
diff -Nraup linux-2.6_tip0413/arch/x86/kvm/x86.c linux-2.6_tip0413_perfkvm/arch/x86/kvm/x86.c
--- linux-2.6_tip0413/arch/x86/kvm/x86.c 2010-04-14 11:11:04.341042024 +0800
+++ linux-2.6_tip0413_perfkvm/arch/x86/kvm/x86.c 2010-04-14 11:32:45.841278890 +0800
@@ -3765,6 +3765,35 @@ static void kvm_timer_init(void)
}
}
+static DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
+
+static int kvm_is_in_guest(void)
+{
+ return percpu_read(current_vcpu) != NULL;
An even more accurate way to determine this is to check whether the
interrupt frame points back at the 'int $2' instruction. However we
plan to switch to a self-IPI method to inject the NMI, and I'm not sure
wether APIC NMIs are accepted on an instruction boundary or whether
there's some latency involved.
+static unsigned long kvm_get_guest_ip(void)
+{
+ unsigned long ip = 0;
+ if (percpu_read(current_vcpu))
+ ip = kvm_rip_read(percpu_read(current_vcpu));
+ return ip;
+}
This may be racy. kvm_rip_read() accesses a cache in memory; if we're
in the process of updating the cache, then we may read a stale value.
See below.
trace_kvm_entry(vcpu->vcpu_id);
+
+ percpu_write(current_vcpu, vcpu);
kvm_x86_ops->run(vcpu);
+ percpu_write(current_vcpu, NULL);
If you move this around the 'int $2' instructions you will close the
race, as a stray NMI won't catch us updating the rip cache. But that
depends on whether self-IPI is accepted on the next instruction or not.
--
error compiling committee.c: too many arguments to function
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