On 29/10/2015 09:22, Liang Li wrote:
> +int kvm_get_tsc(CPUState *cs)
> +{
> + X86CPU *cpu = X86_CPU(cs);
> + CPUX86State *env = &cpu->env;
> + struct {
> + struct kvm_msrs info;
> + struct kvm_msr_entry entries[1];
> + } msr_data;
> + struct kvm_msr_entry *msrs = msr_data.entries;
> + int ret, i, n;
> +
> + n = 0;
> +
> + if (!env->tsc_valid) {
> + msrs[n++].index = MSR_IA32_TSC;
> + env->tsc_valid = !runstate_is_running();
> + }
> +
> + if (n == 0) {
> + return 0;
> + }
> +
> + msr_data.info = (struct kvm_msrs) {
> + .nmsrs = n,
> + };
> +
> + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
> + if (ret < 0) {
> + return ret;
> + }
> +
> + for (i = 0; i < ret; i++) {
> + uint32_t index = msrs[i].index;
> + switch (index) {
> + case MSR_IA32_TSC:
> + env->tsc = msrs[i].data;
> + break;
> + default:
> + break;
> + }
> + }
> +
> + return 0;
> +}
> +
> +
This can be simplified a bit:
int kvm_get_tsc(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
struct {
struct kvm_msrs info;
struct kvm_msr_entry entries[1];
} msr_data;
int ret;
if (env->tsc_valid) {
return 0;
}
msr_data.info.nmsrs = 1;
msr_data.entries[0].index = MSR_IA32_TSC;
env->tsc_valid = !runstate_is_running();
ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
if (ret < 0) {
return ret;
}
env->tsc = msr_data.entries[0].data;
return 0;
}
>
> + CPU_FOREACH(cpu) {
> + ret = kvm_get_tsc(cpu);
> + if (ret < 0) {
> + fprintf(stderr, "KVM_GET_MSRS failed: %s\n", strerror(ret));
> + abort();
> + return;
> + }
> + }
This should be run in the appropriate thread using run_on_cpu. VCPU
ioctls should only be invoked from the VCPU thread. So you should
introduce a new function kvm_synchronize_all_tsc() or something like that.
Otherwise, the idea behind the patches is fine. Thanks!
Paolo
