[PATCH 2/3 v2] KVM: VMX: VMCLEAR/VMPTRLD usage changes.

["Xu, Dongxiao" <dongxiao.xu@xxxxxxxxx>]

From: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>

Originally VMCLEAR/VMPTRLD is called on vcpu migration. To
support hosted VMM coexistance, VMCLEAR is executed on vcpu
schedule out, and VMPTRLD is executed on vcpu schedule in.
This could also eliminate the IPI when doing VMCLEAR.

Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
---
 arch/x86/kvm/vmx.c |   70 +++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 50 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e77da89..aa3b2f9 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -62,6 +62,9 @@ module_param_named(unrestricted_guest,
 static int __read_mostly emulate_invalid_guest_state = 0;
 module_param(emulate_invalid_guest_state, bool, S_IRUGO);
 
+static int __read_mostly vmm_coexistence;
+module_param(vmm_coexistence, 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						\
@@ -222,6 +225,7 @@ static u64 host_efer;
 
 static void ept_save_pdptrs(struct kvm_vcpu *vcpu);
 
+static void vmx_flush_tlb(struct kvm_vcpu *vcpu);
 /*
  * Keep MSR_K6_STAR at the end, as setup_msrs() will try to optimize it
  * away by decrementing the array size.
@@ -784,25 +788,31 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u64 tsc_this, delta, new_offset;
 
-	if (vcpu->cpu != cpu) {
-		vcpu_clear(vmx);
-		kvm_migrate_timers(vcpu);
+	if (vmm_coexistence) {
+		vmcs_load(vmx->vmcs);
 		set_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests);
-		local_irq_disable();
-		list_add(&vmx->local_vcpus_link,
-			 &per_cpu(vcpus_on_cpu, cpu));
-		local_irq_enable();
-	}
+	} else {
+		if (vcpu->cpu != cpu) {
+			vcpu_clear(vmx);
+			set_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests);
+			local_irq_disable();
+			list_add(&vmx->local_vcpus_link,
+					&per_cpu(vcpus_on_cpu, cpu));
+			local_irq_enable();
+		}
 
-	if (per_cpu(current_vmcs, cpu) != vmx->vmcs) {
-		per_cpu(current_vmcs, cpu) = vmx->vmcs;
-		vmcs_load(vmx->vmcs);
+		if (per_cpu(current_vmcs, cpu) != vmx->vmcs) {
+			per_cpu(current_vmcs, cpu) = vmx->vmcs;
+			vmcs_load(vmx->vmcs);
+		}
 	}
 
 	if (vcpu->cpu != cpu) {
 		struct desc_ptr dt;
 		unsigned long sysenter_esp;
 
+		kvm_migrate_timers(vcpu);
+
 		vcpu->cpu = cpu;
 		/*
 		 * Linux uses per-cpu TSS and GDT, so set these when switching
@@ -829,7 +839,14 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
 {
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
 	__vmx_load_host_state(to_vmx(vcpu));
+	if (vmm_coexistence) {
+		vmcs_clear(vmx->vmcs);
+		rdtscll(vmx->vcpu.arch.host_tsc);
+		vmx->launched = 0;
+	}
 }
 
 static void vmx_fpu_activate(struct kvm_vcpu *vcpu)
@@ -1280,7 +1297,8 @@ static void kvm_cpu_vmxoff(void)
 
 static void hardware_disable(void *garbage)
 {
-	vmclear_local_vcpus();
+	if (!vmm_coexistence)
+		vmclear_local_vcpus();
 	kvm_cpu_vmxoff();
 	write_cr4(read_cr4() & ~X86_CR4_VMXE);
 }
@@ -3927,7 +3945,8 @@ static void vmx_free_vmcs(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
 	if (vmx->vmcs) {
-		vcpu_clear(vmx);
+		if (!vmm_coexistence)
+			vcpu_clear(vmx);
 		free_vmcs(vmx->vmcs);
 		vmx->vmcs = NULL;
 	}
@@ -3969,13 +3988,20 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
 	if (!vmx->vmcs)
 		goto free_msrs;
 
-	vmcs_clear(vmx->vmcs);
-
-	cpu = get_cpu();
-	vmx_vcpu_load(&vmx->vcpu, cpu);
-	err = vmx_vcpu_setup(vmx);
-	vmx_vcpu_put(&vmx->vcpu);
-	put_cpu();
+	if (vmm_coexistence) {
+		preempt_disable();
+		vmcs_load(vmx->vmcs);
+		err = vmx_vcpu_setup(vmx);
+		vmcs_clear(vmx->vmcs);
+		preempt_enable();
+	} else {
+		vmcs_clear(vmx->vmcs);
+		cpu = get_cpu();
+		vmx_vcpu_load(&vmx->vcpu, cpu);
+		err = vmx_vcpu_setup(vmx);
+		vmx_vcpu_put(&vmx->vcpu);
+		put_cpu();
+	}
 	if (err)
 		goto free_vmcs;
 	if (vm_need_virtualize_apic_accesses(kvm))
@@ -4116,6 +4142,8 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 
 	vmx->rdtscp_enabled = false;
 	if (vmx_rdtscp_supported()) {
+		if (vmm_coexistence)
+			vmcs_load(vmx->vmcs);
 		exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
 		if (exec_control & SECONDARY_EXEC_RDTSCP) {
 			best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
@@ -4127,6 +4155,8 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (vmm_coexistence)
+			vmcs_clear(vmx->vmcs);
 	}
 }
 
-- 
1.6.3
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