KVM: x86: Route non-canonical checks in emulator through emulate_ops

Add emulate_ops.is_canonical_addr() to perform (non-)canonical checks in
the emulator, which will allow extending is_noncanonical_address() to
support different flavors of canonical checks, e.g. for descriptor table
bases vs. MSRs, without needing duplicate logic in the emulator.

No functional change is intended.

Signed-off-by: Maxim Levitsky <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[sean: separate from additional of flags, massage changelog]
Signed-off-by: Sean Christopherson <[email protected]>

Author: Maxim Levitsky

arch/x86/kvm/emulate.c

@@ -653,7 +653,7 @@ static inline u8 ctxt_virt_addr_bits(struct x86_emulate_ctxt *ctxt)
 static inline bool emul_is_noncanonical_address(u64 la,
 						struct x86_emulate_ctxt *ctxt)
 {
-	return !__is_canonical_address(la, ctxt_virt_addr_bits(ctxt));
+	return !ctxt->ops->is_canonical_addr(ctxt, la);
 }
 
 /*

arch/x86/kvm/kvm_emulate.h

@@ -235,6 +235,8 @@ struct x86_emulate_ops {
 
 	gva_t (*get_untagged_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
 				   unsigned int flags);
+
+	bool (*is_canonical_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr);
 };
 
 /* Type, address-of, and value of an instruction's operand. */

arch/x86/kvm/x86.c

@@ -8619,6 +8619,12 @@ static gva_t emulator_get_untagged_addr(struct x86_emulate_ctxt *ctxt,
 					       addr, flags);
 }
 
+static bool emulator_is_canonical_addr(struct x86_emulate_ctxt *ctxt,
+				       gva_t addr)
+{
+	return !is_noncanonical_address(addr, emul_to_vcpu(ctxt));
+}
+
 static const struct x86_emulate_ops emulate_ops = {
 	.vm_bugged           = emulator_vm_bugged,
 	.read_gpr            = emulator_read_gpr,
@@ -8665,6 +8671,7 @@ static const struct x86_emulate_ops emulate_ops = {
 	.triple_fault        = emulator_triple_fault,
 	.set_xcr             = emulator_set_xcr,
 	.get_untagged_addr   = emulator_get_untagged_addr,
+	.is_canonical_addr   = emulator_is_canonical_addr,
 };
 
 static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)