KVM: x86: Use KVM_REQ_TLB_FLUSH_GUEST to handle INVPCID(ALL) emulation

Use KVM_REQ_TLB_FLUSH_GUEST instead of KVM_REQ_MMU_RELOAD when emulating
INVPCID of all contexts.  In the current code, this is a glorified nop as
TLB_FLUSH_GUEST becomes kvm_mmu_unload(), same as MMU_RELOAD, when TDP
is disabled, which is the only time INVPCID is only intercepted+emulated.
In the future, reusing TLB_FLUSH_GUEST will simplify optimizing paths
that emulate a guest TLB flush, e.g. by synchronizing as needed instead
of completely unloading all MMUs.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-11-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -12031,7 +12031,7 @@ int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva)
 
 		fallthrough;
 	case INVPCID_TYPE_ALL_INCL_GLOBAL:
-		kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
+		kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu);
 		return kvm_skip_emulated_instruction(vcpu);
 
 	default: