[PATCH v1 4/6] KVM: x86: Add emulator helper for LASS violation check

[Zeng Guang]

When LASS is enabled, KVM need apply LASS violation check to instruction
emulations. Add helper for the usage of x86 emulator to perform LASS
protection.

Signed-off-by: Zeng Guang <guang.zeng@xxxxxxxxx>
Tested-by: Xuelian Guo <xuelian.guo@xxxxxxxxx>
---
 arch/x86/kvm/kvm_emulate.h |  1 +
 arch/x86/kvm/x86.c         | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index f1439ab7c14b..fd1c2b22867e 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -230,6 +230,7 @@ struct x86_emulate_ops {
 	int (*leave_smm)(struct x86_emulate_ctxt *ctxt);
 	void (*triple_fault)(struct x86_emulate_ctxt *ctxt);
 	int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr);
+	bool (*check_lass)(struct x86_emulate_ctxt *ctxt, u64 access, u64 la, u32 flags);
 };
 
 /* Type, address-of, and value of an instruction's operand. */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c0778ca39650..faf01fecc4ca 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8287,6 +8287,17 @@ static void emulator_vm_bugged(struct x86_emulate_ctxt *ctxt)
 		kvm_vm_bugged(kvm);
 }
 
+static bool emulator_check_lass(struct x86_emulate_ctxt *ctxt,
+				u64 access, u64 la, u32 flags)
+{
+	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+	if (!is_long_mode(vcpu))
+		return false;
+
+	return static_call(kvm_x86_check_lass)(vcpu, access, la, flags);
+}
+
 static const struct x86_emulate_ops emulate_ops = {
 	.vm_bugged           = emulator_vm_bugged,
 	.read_gpr            = emulator_read_gpr,
@@ -8332,6 +8343,7 @@ static const struct x86_emulate_ops emulate_ops = {
 	.leave_smm           = emulator_leave_smm,
 	.triple_fault        = emulator_triple_fault,
 	.set_xcr             = emulator_set_xcr,
+	.check_lass          = emulator_check_lass,
 };
 
 static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
-- 
2.27.0