On 12/16/2009 07:48 AM, Sheng Yang wrote:
shared_msr_global saved host value of relevant MSRs, but it have an
assumption that all MSRs it tracked shared the value across the different
CPUs. It's not true with some MSRs, e.g. MSR_TSC_AUX.
Extend it to per CPU to provide the support of MSR_TSC_AUX, and more
alike MSRs.
Notice now the shared_msr_global still have one assumption: it can only deal
with the MSRs that won't change in host after KVM module loaded.
-void kvm_define_shared_msr(unsigned slot, u32 msr)
+static void shared_msr_update(void *data)
{
- int cpu;
+ struct kvm_shared_msrs *smsr;
+ u32 msr = *(u32 *)data;
+ int slot;
u64 value;
+ smsr =&get_cpu_var(shared_msrs);
Can use __get_cpu_var() since interrupts are disabled.
+ /* only read, and nobody should modify it at this time,
+ * so don't need lock */
+ for (slot = 0; slot< shared_msrs_global.nr; slot++)
+ if (shared_msrs_global.msrs[slot] == msr)
+ break;
+ if (slot>= shared_msrs_global.nr) {
+ printk(KERN_ERR "kvm: can't find the defined MSR!");
+ return;
+ }
+ rdmsrl_safe(msr,&value);
+ smsr->values[slot].host = value;
+ smsr->values[slot].curr = value;
+ put_cpu_var(shared_msrs);
+}
+
+void kvm_define_shared_msr(unsigned slot, u32 msr)
+{
if (slot>= shared_msrs_global.nr)
shared_msrs_global.nr = slot + 1;
- shared_msrs_global.msrs[slot].msr = msr;
- rdmsrl_safe(msr,&value);
- shared_msrs_global.msrs[slot].value = value;
- for_each_online_cpu(cpu)
- per_cpu(shared_msrs, cpu).current_value[slot] = value;
+ shared_msrs_global.msrs[slot] = msr;
+ /* we need ensured the shared_msr_global have been updated */
+ smp_wmb();
+ smp_call_function(shared_msr_update,&msr, 1);
on_each_cpu() is preferred.
+ shared_msr_update(&msr);
}
EXPORT_SYMBOL_GPL(kvm_define_shared_msr);
static void kvm_shared_msr_cpu_online(void)
{
unsigned i;
- struct kvm_shared_msrs *locals =&__get_cpu_var(shared_msrs);
+ struct kvm_shared_msrs *smsr =&__get_cpu_var(shared_msrs);
for (i = 0; i< shared_msrs_global.nr; ++i)
- locals->current_value[i] = shared_msrs_global.msrs[i].value;
+ smsr->values[i].curr = smsr->values[i].host;
If the cpu is being onlined for the first time, then .host will not have
been initialized. Need to call shared_msr_update().
Also need to verify this is called after all the msrs have been
initialized by the kernel, or we'll read default values.
--
error compiling committee.c: too many arguments to function
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