Question

我遇到了在qemu-kvm上捕获性能监视中断（PMI - 特别是指令计数器）的情况。下面的代码在真机（Intel Core TM i5-4300U）上运行良好，但在qemu-kvm（qemu-system-x86_64 -cpu主机）上，我甚至看不到一个PMI。虽然柜台正常工作。我可以检查它增量很好。

但是，我已经使用Linux内核进行了测试，它在同一个qemu-kvm上很好地捕获了溢出中断。因此，在Qemu-kvm上配置性能监视计数器时，显然我缺少一个步骤。

有人能指出我吗？这是伪代码：

#define LAPIC_SVR           0xF0
#define LAPIC_LVT_PERFM      0x340,
#define CPU_LOCAL_APIC      0xFFFFFFFFBFFFE000
#define NMI_DELIVERY_MODE    0x4 << 8                            //NMI
#define MSR_PERF_GLOBAL_CTRL    0x38F
#define MSR_PERF_FIXED_CTRL     0x38D
#define MSR_PERF_FIXED_CTR0     0x309
#define MSR_PERF_GLOBAL_OVF_CTRL 0x390

/*Configure LAPIC*/
apic_base = Msr::read<Paddr>(Msr::IA32_APIC_BASE)
map(CPU_LOCAL_APIC, apic_base & 0xFFFFF000)                                                                // No caching, etc.
Msr::write (Msr::IA32_APIC_BASE, apic_base | 0x800);
write (LAPIC_SVR, read (LAPIC_SVR) | 0x100);
*reinterpret_cast<uint32 volatile *>(CPU_LOCAL_APIC + LAPIC_LVT_PERFM) = NMI_DELIVERY_MODE;

/*Configure MSR_PERF_FIXED_CTR0 to have overflow interrupt*/
Msr::write(Msr::MSR_PERF_GLOBAL_CTRL, Msr::read<uint64>(Msr::MSR_PERF_GLOBAL_CTRL) | (1ull<<32));          // enable IA32_PERF_FIXED_CTR0
Msr::write(Msr::MSR_PERF_FIXED_CTRL, 0xa);                                                                 // configure IA32_PERF_FIXED_CTR0 to count in user mode and interrupt on overflow
Msr::write(Msr::MSR_PERF_FIXED_CTR0, (1<<48) - 0x1000);                                                    // overflow after 0x1000 instruction
Msr::write(Msr::MSR_PERF_GLOBAL_OVF_CTRL, Msr::read<uint64>(Msr::MSR_PERF_GLOBAL_OVF_CTRL) & ~(1UL<<32));  // clear overflow condition

在Qemu-Kvm上获取性能监视中断

0 个答案: