kvm-vmx: add module parameter to avoid trapping HLT instructions (v3)

Commit Message

Anthony Liguori Dec. 3, 2010, 10:39 p.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 42d9590..9642c22 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -297,6 +297,12 @@  enum vmcs_field {
 #define GUEST_INTR_STATE_SMI		0x00000004
 #define GUEST_INTR_STATE_NMI		0x00000008
 
+/* GUEST_ACTIVITY_STATE flags */
+#define GUEST_ACTIVITY_ACTIVE		0
+#define GUEST_ACTIVITY_HLT		1
+#define GUEST_ACTIVITY_SHUTDOWN		2
+#define GUEST_ACTIVITY_WAIT_SIPI	3
+
 /*
  * Exit Qualifications for MOV for Control Register Access
  */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index caa967e..e8e64cb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -69,6 +69,9 @@  module_param(emulate_invalid_guest_state, bool, S_IRUGO);
 static int __read_mostly vmm_exclusive = 1;
 module_param(vmm_exclusive, bool, S_IRUGO);
 
+static int yield_on_hlt = 1;
+module_param(yield_on_hlt, bool, S_IRUGO);
+
 #define KVM_GUEST_CR0_MASK_UNRESTRICTED_GUEST				\
 	(X86_CR0_WP | X86_CR0_NE | X86_CR0_NW | X86_CR0_CD)
 #define KVM_GUEST_CR0_MASK						\
@@ -1016,6 +1019,10 @@  static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 intr_info = nr | INTR_INFO_VALID_MASK;
 
+        /* Cannot inject an exception in guest activity state is HLT */
+	if (vmcs_read32(GUEST_ACTIVITY_STATE) == GUEST_ACTIVITY_HLT)
+		vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE);
+
 	if (has_error_code) {
 		vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
 		intr_info |= INTR_INFO_DELIVER_CODE_MASK;
@@ -1419,7 +1426,7 @@  static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 				&_pin_based_exec_control) < 0)
 		return -EIO;
 
-	min = CPU_BASED_HLT_EXITING |
+	min =
 #ifdef CONFIG_X86_64
 	      CPU_BASED_CR8_LOAD_EXITING |
 	      CPU_BASED_CR8_STORE_EXITING |
@@ -1432,6 +1439,10 @@  static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 	      CPU_BASED_MWAIT_EXITING |
 	      CPU_BASED_MONITOR_EXITING |
 	      CPU_BASED_INVLPG_EXITING;
+
+	if (yield_on_hlt)
+		min |= CPU_BASED_HLT_EXITING;
+
 	opt = CPU_BASED_TPR_SHADOW |
 	      CPU_BASED_USE_MSR_BITMAPS |
 	      CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;