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KVM: nVMX: Add support for rdtscp

PATCH Superseded Jan Kiszka 3 participants 7 messages Mar 23, 2015 – Mar 27, 2015

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Jan Kiszka

author
#0 lore raw

PATCH 1/1 KVM: nVMX: Add support for rdtscp

From: Jan Kiszka <[email protected]>

If the guest CPU is supposed to support rdtscp and the host has rdtscp enabled in the secondary execution controls, we can also expose this feature to L1. Just extend nested_vmx_exit_handled to properly route EXIT_REASON_RDTSCP.

Signed-off-by Jan Kiszka <[email protected]>
---
 arch/x86/include/uapi/asm/vmx.h | 1 +
 arch/x86/kvm/vmx.c              | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)
arch/x86/include/uapi/asm/vmx.h +1 -0
index c5f1a1d..1fe9218 100644
@@ -67,6 +67,7 @@
 #define EXIT_REASON_EPT_VIOLATION       48
 #define EXIT_REASON_EPT_MISCONFIG       49
 #define EXIT_REASON_INVEPT              50
+#define EXIT_REASON_RDTSCP              51
 #define EXIT_REASON_PREEMPTION_TIMER    52
 #define EXIT_REASON_INVVPID             53
 #define EXIT_REASON_WBINVD              54
arch/x86/kvm/vmx.c +5 -1
index 50c675b..7875e9b 100644
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (!vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;
 	}
 
 	/* Exposing INVPCID only when PCID is exposed */
Signature · 1 line
2.1.4
author
#1 lore raw

PATCH v2 1/1 KVM: nVMX: Add support for rdtscp

From: Jan Kiszka <[email protected]>

If the guest CPU is supposed to support rdtscp and the host has rdtscp enabled in the secondary execution controls, we can also expose this feature to L1. Just extend nested_vmx_exit_handled to properly route EXIT_REASON_RDTSCP.

Signed-off-by Jan Kiszka <[email protected]>

---

Changes in v2 (thinko in test scenario...):
- respect L1's setting of SECONDARY_EXEC_RDTSCP

 arch/x86/include/uapi/asm/vmx.h | 1 +
 arch/x86/kvm/vmx.c              | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)
arch/x86/include/uapi/asm/vmx.h +1 -0
index c5f1a1d..1fe9218 100644
@@ -67,6 +67,7 @@
 #define EXIT_REASON_EPT_VIOLATION       48
 #define EXIT_REASON_EPT_MISCONFIG       49
 #define EXIT_REASON_INVEPT              50
+#define EXIT_REASON_RDTSCP              51
 #define EXIT_REASON_PREEMPTION_TIMER    52
 #define EXIT_REASON_INVVPID             53
 #define EXIT_REASON_WBINVD              54
arch/x86/kvm/vmx.c +7 -2
index 50c675b..45e0a6b 100644
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (!vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;
 	}
 
 	/* Exposing INVPCID only when PCID is exposed */

@@ -9146,8 +9150,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			exec_control &= ~SECONDARY_EXEC_RDTSCP;
 		/* Take the following fields only from vmcs12 */
 		exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+				  SECONDARY_EXEC_RDTSCP |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
-                                  SECONDARY_EXEC_APIC_REGISTER_VIRT);
+				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
 		if (nested_cpu_has(vmcs12,
 				CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 			exec_control |= vmcs12->secondary_vm_exec_control;
Signature · 1 line
2.1.4
#2 lore raw

Jan Kiszka <[email protected]> writes:
...

Quoted 20 lines
arch/x86/kvm/vmx.c +2 -1
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

arch/x86/kvm/vmx.c static void vmx_cpuid_update(struct kvm_vcpu *vcpu) · line 8523

Quoted 6 lines
arch/x86/kvm/vmx.c +3 -0
@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (!vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;

No need to do this if nested is not enabled ? Or just
a "if (nested)" in the prior if else loop should be enough I think.

Bandan

Quoted 14 lines
arch/x86/kvm/vmx.c +2 -1
 	}
 
 	/* Exposing INVPCID only when PCID is exposed */

@@ -9146,8 +9150,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			exec_control &= ~SECONDARY_EXEC_RDTSCP;
 		/* Take the following fields only from vmcs12 */
 		exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+				  SECONDARY_EXEC_RDTSCP |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
-                                  SECONDARY_EXEC_APIC_REGISTER_VIRT);
+				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
 		if (nested_cpu_has(vmcs12,
 				CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 			exec_control |= vmcs12->secondary_vm_exec_control;
author
#3 lore raw
Quoted 22 lines · Bandan Das

Jan Kiszka <[email protected]> writes:
...

Quoted 20 lines
arch/x86/kvm/vmx.c +2 -1
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
Quoted 8 lines

arch/x86/kvm/vmx.c static void vmx_cpuid_update(struct kvm_vcpu *vcpu) · line 8523

Quoted 6 lines
arch/x86/kvm/vmx.c +3 -0
 						exec_control);
 			}
 		}
+		if (!vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;

No need to do this if nested is not enabled ? Or just
a "if (nested)" in the prior if else loop should be enough I think.

I can add this - but this is far away from being a hotpath. What would be the benefit?

Thanks,
Jan

#4 lore raw
Quoted 32 lines · Jan Kiszka
Quoted 22 lines · Bandan Das

Jan Kiszka <[email protected]> writes:
...

Quoted 20 lines
arch/x86/kvm/vmx.c +2 -1
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
Quoted 8 lines

arch/x86/kvm/vmx.c static void vmx_cpuid_update(struct kvm_vcpu *vcpu) · line 8523

Quoted 6 lines
arch/x86/kvm/vmx.c +3 -0
 						exec_control);
 			}
 		}
+		if (!vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;

No need to do this if nested is not enabled ? Or just
a "if (nested)" in the prior if else loop should be enough I think.

Quoted 2 lines

I can add this - but this is far away from being a hotpath. What would be the benefit?

Right, definitely not a hotpath, just seems unnecessary if nested is not enabled.

Bandan

Quoted 2 lines

Thanks,
Jan

author
#5 lore raw

PATCH v3 1/1 KVM: nVMX: Add support for rdtscp

From: Jan Kiszka <[email protected]>

If the guest CPU is supposed to support rdtscp and the host has rdtscp enabled in the secondary execution controls, we can also expose this feature to L1. Just extend nested_vmx_exit_handled to properly route EXIT_REASON_RDTSCP.

Signed-off-by Jan Kiszka <[email protected]>

---

Changes in v3:
- avoid needlessly touching vmx->nested if nested is off

 arch/x86/include/uapi/asm/vmx.h | 1 +
 arch/x86/kvm/vmx.c              | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)
arch/x86/include/uapi/asm/vmx.h +1 -0
index c5f1a1d..1fe9218 100644
@@ -67,6 +67,7 @@
 #define EXIT_REASON_EPT_VIOLATION       48
 #define EXIT_REASON_EPT_MISCONFIG       49
 #define EXIT_REASON_INVEPT              50
+#define EXIT_REASON_RDTSCP              51
 #define EXIT_REASON_PREEMPTION_TIMER    52
 #define EXIT_REASON_INVVPID             53
 #define EXIT_REASON_WBINVD              54
arch/x86/kvm/vmx.c +7 -2
index 50c675b..fdd9f8b 100644
@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |

@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:

@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (nested && !vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;
 	}
 
 	/* Exposing INVPCID only when PCID is exposed */

@@ -9146,8 +9150,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			exec_control &= ~SECONDARY_EXEC_RDTSCP;
 		/* Take the following fields only from vmcs12 */
 		exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+				  SECONDARY_EXEC_RDTSCP |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
-                                  SECONDARY_EXEC_APIC_REGISTER_VIRT);
+				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
 		if (nested_cpu_has(vmcs12,
 				CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 			exec_control |= vmcs12->secondary_vm_exec_control;
Signature · 1 line
2.1.4
Applied
#6 lore raw
Quoted 8 lines · Jan Kiszka

From: Jan Kiszka <[email protected]>

If the guest CPU is supposed to support rdtscp and the host has rdtscp enabled in the secondary execution controls, we can also expose this feature to L1. Just extend nested_vmx_exit_handled to properly route EXIT_REASON_RDTSCP.

Signed-off-by Jan Kiszka <[email protected]>

Applied, thanks.