[PATCH v3 15/34] KVM: x86: hyper-v: Introduce kvm_hv_is_tlb_flush_hcall()

[Vitaly Kuznetsov]

The newly introduced helper checks whether vCPU is performing a
Hyper-V TLB flush hypercall. This is required to filter out L2 TLB
flush hypercalls for processing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/kvm/hyperv.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index d59f96700104..ca67c18cef2c 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -170,6 +170,24 @@ static inline void kvm_hv_vcpu_empty_flush_tlb(struct kvm_vcpu *vcpu)
 	tlb_flush_ring = kvm_hv_get_tlb_flush_ring(vcpu);
 	tlb_flush_ring->read_idx = tlb_flush_ring->write_idx;
 }
+
+static inline bool kvm_hv_is_tlb_flush_hcall(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
+	u16 code;
+
+	if (!hv_vcpu)
+		return false;
+
+	code = is_64_bit_hypercall(vcpu) ? kvm_rcx_read(vcpu) :
+		kvm_rax_read(vcpu);
+
+	return (code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE ||
+		code == HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST ||
+		code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX ||
+		code == HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX);
+}
+
 void kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu);
 
 
-- 
2.35.1