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/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7ff0ea3..fe4df46 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -521,6 +521,7 @@ struct kvm_x86_ops {
        int (*get_tdp_level)(void);
        u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
        bool (*gb_page_enable)(void);
+       bool (*rdtscp_supported)(void);
 
        const struct trace_print_flags *exit_reasons_str;
 };

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 8f6b011..713ed9a 100644 (file)
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -53,6 +53,7 @@
  */
 #define SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES 0x00000001
 #define SECONDARY_EXEC_ENABLE_EPT               0x00000002
+#define SECONDARY_EXEC_RDTSCP                  0x00000008
 #define SECONDARY_EXEC_ENABLE_VPID              0x00000020
 #define SECONDARY_EXEC_WBINVD_EXITING          0x00000040
 #define SECONDARY_EXEC_UNRESTRICTED_GUEST      0x00000080

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 41777e6..7f4e225 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2914,6 +2914,11 @@ static bool svm_gb_page_enable(void)
        return true;
 }
 
+static bool svm_rdtscp_supported(void)
+{
+       return false;
+}
+
 static struct kvm_x86_ops svm_x86_ops = {
        .cpu_has_kvm_support = has_svm,
        .disabled_by_bios = is_disabled,
@@ -2982,6 +2987,8 @@ static struct kvm_x86_ops svm_x86_ops = {
        .gb_page_enable = svm_gb_page_enable,
 
        .cpuid_update = svm_cpuid_update,
+
+       .rdtscp_supported = svm_rdtscp_supported,
 };
 
 static int __init svm_init(void)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 75e8931..74a66f0 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -151,6 +151,8 @@ struct vcpu_vmx {
        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 @@ static const u32 vmx_msr_index[] = {
 #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 @@ static inline int cpu_has_vmx_vpid(void)
                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 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
        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 @@ static void setup_msrs(struct vcpu_vmx *vmx)
                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 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
        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 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
                        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 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
                        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 @@ static bool vmx_gb_page_enable(void)
        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 @@ static struct kvm_x86_ops vmx_x86_ops = {
        .gb_page_enable = vmx_gb_page_enable,
 
        .cpuid_update = vmx_cpuid_update,
+
+       .rdtscp_supported = vmx_rdtscp_supported,
 };
 
 static int __init vmx_init(void)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5ac21f..8798504 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1646,6 +1646,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 #else
        unsigned f_lm = 0;
 #endif
+       unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
 
        /* cpuid 1.edx */
        const u32 kvm_supported_word0_x86_features =
@@ -1665,7 +1666,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
                F(PAT) | F(PSE36) | 0 /* Reserved */ |
                f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
-               F(FXSR) | F(FXSR_OPT) | f_gbpages | 0 /* RDTSCP */ |
+               F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
                0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
        /* cpuid 1.ecx */
        const u32 kvm_supported_word4_x86_features =