[PATCH v12 22/46] 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.

Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/kvm/hyperv.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 8942e8c6c912..5f9c76b45f46 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -177,6 +177,23 @@ static inline void kvm_hv_vcpu_purge_flush_tlb(struct kvm_vcpu *vcpu)
 	kfifo_reset_out(&tlb_flush_fifo->entries);
 }
 
+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);
+}
+
 int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu);
 
 #endif
-- 
2.37.3