Commit 4e47c7a6 authored by Sheng Yang's avatar Sheng Yang Committed by Marcelo Tosatti
Browse files

KVM: VMX: Add instruction rdtscp support for guest 



Before enabling, execution of "rdtscp" in guest would result in #UD.

Signed-off-by: default avatarSheng Yang <sheng@linux.intel.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 0e851880

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

arch/x86/include/asm/vmx.h

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kvm/svm.c

+7 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/kvm/vmx.c

+57 −3
Original line number Diff line number Diff line
@@ -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)

arch/x86/kvm/x86.c

+2 −1
Original line number Diff line number Diff line
@@ -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 =