KVM: VMX: Add instruction rdtscp support for guest
Before enabling, execution of "rdtscp" in guest would result in #UD.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 75e8931..74a66f0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -151,6 +151,8 @@
ktime_t entry_time;
s64 vnmi_blocked_time;
u32 exit_reason;
+
+ bool rdtscp_enabled;
};
static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
@@ -225,7 +227,7 @@
#ifdef CONFIG_X86_64
MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR,
#endif
- MSR_EFER, MSR_K6_STAR,
+ MSR_EFER, MSR_TSC_AUX, MSR_K6_STAR,
};
#define NR_VMX_MSR ARRAY_SIZE(vmx_msr_index)
@@ -362,6 +364,12 @@
SECONDARY_EXEC_ENABLE_VPID;
}
+static inline int cpu_has_vmx_rdtscp(void)
+{
+ return vmcs_config.cpu_based_2nd_exec_ctrl &
+ SECONDARY_EXEC_RDTSCP;
+}
+
static inline int cpu_has_virtual_nmis(void)
{
return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
@@ -893,6 +901,11 @@
vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
}
+static bool vmx_rdtscp_supported(void)
+{
+ return cpu_has_vmx_rdtscp();
+}
+
/*
* Swap MSR entry in host/guest MSR entry array.
*/
@@ -928,6 +941,9 @@
index = __find_msr_index(vmx, MSR_CSTAR);
if (index >= 0)
move_msr_up(vmx, index, save_nmsrs++);
+ index = __find_msr_index(vmx, MSR_TSC_AUX);
+ if (index >= 0 && vmx->rdtscp_enabled)
+ move_msr_up(vmx, index, save_nmsrs++);
/*
* MSR_K6_STAR is only needed on long mode guests, and only
* if efer.sce is enabled.
@@ -1017,6 +1033,10 @@
case MSR_IA32_SYSENTER_ESP:
data = vmcs_readl(GUEST_SYSENTER_ESP);
break;
+ case MSR_TSC_AUX:
+ if (!to_vmx(vcpu)->rdtscp_enabled)
+ return 1;
+ /* Otherwise falls through */
default:
vmx_load_host_state(to_vmx(vcpu));
msr = find_msr_entry(to_vmx(vcpu), msr_index);
@@ -1080,7 +1100,15 @@
vcpu->arch.pat = data;
break;
}
- /* Otherwise falls through to kvm_set_msr_common */
+ ret = kvm_set_msr_common(vcpu, msr_index, data);
+ break;
+ case MSR_TSC_AUX:
+ if (!vmx->rdtscp_enabled)
+ return 1;
+ /* Check reserved bit, higher 32 bits should be zero */
+ if ((data >> 32) != 0)
+ return 1;
+ /* Otherwise falls through */
default:
msr = find_msr_entry(vmx, msr_index);
if (msr) {
@@ -1260,7 +1288,8 @@
SECONDARY_EXEC_ENABLE_VPID |
SECONDARY_EXEC_ENABLE_EPT |
SECONDARY_EXEC_UNRESTRICTED_GUEST |
- SECONDARY_EXEC_PAUSE_LOOP_EXITING;
+ SECONDARY_EXEC_PAUSE_LOOP_EXITING |
+ SECONDARY_EXEC_RDTSCP;
if (adjust_vmx_controls(min2, opt2,
MSR_IA32_VMX_PROCBASED_CTLS2,
&_cpu_based_2nd_exec_control) < 0)
@@ -3988,8 +4017,31 @@
return false;
}
+static inline u32 bit(int bitno)
+{
+ return 1 << (bitno & 31);
+}
+
static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
{
+ struct kvm_cpuid_entry2 *best;
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ u32 exec_control;
+
+ vmx->rdtscp_enabled = false;
+ if (vmx_rdtscp_supported()) {
+ exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
+ if (exec_control & SECONDARY_EXEC_RDTSCP) {
+ best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+ if (best && (best->edx & bit(X86_FEATURE_RDTSCP)))
+ vmx->rdtscp_enabled = true;
+ else {
+ exec_control &= ~SECONDARY_EXEC_RDTSCP;
+ vmcs_write32(SECONDARY_VM_EXEC_CONTROL,
+ exec_control);
+ }
+ }
+ }
}
static struct kvm_x86_ops vmx_x86_ops = {
@@ -4058,6 +4110,8 @@
.gb_page_enable = vmx_gb_page_enable,
.cpuid_update = vmx_cpuid_update,
+
+ .rdtscp_supported = vmx_rdtscp_supported,
};
static int __init vmx_init(void)