Untangle TPR shadowing and APIC virtualization on VT-x (against 13-CURRENT r355978)

tpr_shadowing.diff

diff --git a/sys/amd64/vmm/intel/vmx.c b/sys/amd64/vmm/intel/vmx.c
index 605fd0bda766..324a1e9d0c3c 100644
--- a/sys/amd64/vmm/intel/vmx.c
+++ b/sys/amd64/vmm/intel/vmx.c
@@ -172,6 +172,10 @@ static int cap_invpcid;
 SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, invpcid, CTLFLAG_RD, &cap_invpcid,
     0, "Guests are allowed to use INVPCID");
 
+static int tpr_shadowing;
+SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, tpr_shadowing, CTLFLAG_RD,
+    &tpr_shadowing, 0, "TPR shadowin support");
+
 static int virtual_interrupt_delivery;
 SYSCTL_INT(_hw_vmm_vmx_cap, OID_AUTO, virtual_interrupt_delivery, CTLFLAG_RD,
     &virtual_interrupt_delivery, 0, "APICv virtual interrupt delivery support");
@@ -627,7 +631,7 @@ vmx_restore(void)
 static int
 vmx_init(int ipinum)
 {
-	int error, use_tpr_shadow;
+	int error;
 	uint64_t basic, fixed0, fixed1, feature_control;
 	uint32_t tmp, procbased2_vid_bits;
 
@@ -750,6 +754,24 @@ vmx_init(int ipinum)
 	    MSR_VMX_PROCBASED_CTLS2, PROCBASED2_ENABLE_INVPCID, 0,
 	    &tmp) == 0);
 
+	/*
+	 * Check support for TPR shadow.
+	 */
+	error = vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS,
+	    MSR_VMX_TRUE_PROCBASED_CTLS, PROCBASED_USE_TPR_SHADOW, 0,
+	    &tmp);
+	if (error == 0) {
+		tpr_shadowing = 1;
+		TUNABLE_INT_FETCH("hw.vmm.vmx.use_tpr_shadowing",
+		    &tpr_shadowing);
+	}
+
+	if (tpr_shadowing) {
+		procbased_ctls |= PROCBASED_USE_TPR_SHADOW;
+		procbased_ctls &= ~PROCBASED_CR8_LOAD_EXITING;
+		procbased_ctls &= ~PROCBASED_CR8_STORE_EXITING;
+	}
+
 	/*
 	 * Check support for virtual interrupt delivery.
 	 */
@@ -758,13 +780,9 @@ vmx_init(int ipinum)
 	    PROCBASED2_APIC_REGISTER_VIRTUALIZATION |
 	    PROCBASED2_VIRTUAL_INTERRUPT_DELIVERY);
 
-	use_tpr_shadow = (vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS,
-	    MSR_VMX_TRUE_PROCBASED_CTLS, PROCBASED_USE_TPR_SHADOW, 0,
-	    &tmp) == 0);
-
 	error = vmx_set_ctlreg(MSR_VMX_PROCBASED_CTLS2, MSR_VMX_PROCBASED_CTLS2,
 	    procbased2_vid_bits, 0, &tmp);
-	if (error == 0 && use_tpr_shadow) {
+	if (error == 0 && tpr_shadowing) {
 		virtual_interrupt_delivery = 1;
 		TUNABLE_INT_FETCH("hw.vmm.vmx.use_apic_vid",
 		    &virtual_interrupt_delivery);
@@ -775,13 +793,6 @@ vmx_init(int ipinum)
 		procbased_ctls2 |= procbased2_vid_bits;
 		procbased_ctls2 &= ~PROCBASED2_VIRTUALIZE_X2APIC_MODE;
 
-		/*
-		 * No need to emulate accesses to %CR8 if virtual
-		 * interrupt delivery is enabled.
-		 */
-		procbased_ctls &= ~PROCBASED_CR8_LOAD_EXITING;
-		procbased_ctls &= ~PROCBASED_CR8_STORE_EXITING;
-
 		/*
 		 * Check for Posted Interrupts only if Virtual Interrupt
 		 * Delivery is enabled.
@@ -1051,10 +1062,13 @@ vmx_vminit(struct vm *vm, pmap_t pmap)
 		vmx->ctx[i].guest_dr6 = DBREG_DR6_RESERVED1;
 		error += vmwrite(VMCS_GUEST_DR7, DBREG_DR7_RESERVED1);
 
-		if (virtual_interrupt_delivery) {
-			error += vmwrite(VMCS_APIC_ACCESS, APIC_ACCESS_ADDRESS);
+		if (tpr_shadowing) {
 			error += vmwrite(VMCS_VIRTUAL_APIC,
 			    vtophys(&vmx->apic_page[i]));
+		}
+
+		if (virtual_interrupt_delivery) {
+			error += vmwrite(VMCS_APIC_ACCESS, APIC_ACCESS_ADDRESS);
 			error += vmwrite(VMCS_EOI_EXIT0, 0);
 			error += vmwrite(VMCS_EOI_EXIT1, 0);
 			error += vmwrite(VMCS_EOI_EXIT2, 0);
@@ -2313,6 +2327,14 @@ vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
 		}
 	}
 
+	/*
+	 * If 'TPR shadowing' is used, update the local APICs PPR.
+	 */
+	if (tpr_shadowing) {
+		vlapic = vm_lapic(vmx->vm, vcpu);
+		vlapic_update_ppr(vlapic);
+	}
+
 	switch (reason) {
 	case EXIT_REASON_TASK_SWITCH:
 		ts = &vmexit->u.task_switch;
diff --git a/sys/amd64/vmm/io/vlapic.c b/sys/amd64/vmm/io/vlapic.c
index 74e6cd967396..289fdb7e077d 100644
--- a/sys/amd64/vmm/io/vlapic.c
+++ b/sys/amd64/vmm/io/vlapic.c
@@ -490,7 +490,7 @@ dump_isrvec_stk(struct vlapic *vlapic)
  * Algorithm adopted from section "Interrupt, Task and Processor Priority"
  * in Intel Architecture Manual Vol 3a.
  */
-static void
+void
 vlapic_update_ppr(struct vlapic *vlapic)
 {
 	int isrvec, tpr, ppr;
diff --git a/sys/amd64/vmm/io/vlapic.h b/sys/amd64/vmm/io/vlapic.h
index 2a5f54003253..71b97feab6bc 100644
--- a/sys/amd64/vmm/io/vlapic.h
+++ b/sys/amd64/vmm/io/vlapic.h
@@ -74,6 +74,8 @@ void vlapic_post_intr(struct vlapic *vlapic, int hostcpu, int ipinum);
 void vlapic_fire_cmci(struct vlapic *vlapic);
 int vlapic_trigger_lvt(struct vlapic *vlapic, int vector);
 
+void vlapic_update_ppr(struct vlapic *vlapic);
+
 uint64_t vlapic_get_apicbase(struct vlapic *vlapic);
 int vlapic_set_apicbase(struct vlapic *vlapic, uint64_t val);
 void vlapic_set_x2apic_state(struct vm *vm, int vcpuid, enum x2apic_state s);