Commit 4aa2691d authored by Wei Huang's avatar Wei Huang Committed by Paolo Bonzini
Browse files

KVM: x86: Factor out x86 instruction emulation with decoding 



Move the instruction decode part out of x86_emulate_instruction() for it
to be used in other places. Also kvm_clear_exception_queue() is moved
inside the if-statement as it doesn't apply when KVM are coming back from
userspace.

Co-developed-by: default avatarBandan Das <bsd@redhat.com>
Signed-off-by: default avatarBandan Das <bsd@redhat.com>
Signed-off-by: default avatarWei Huang <wei.huang2@amd.com>
Message-Id: <20210126081831.570253-2-wei.huang2@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9a3ecd5e

arch/x86/kvm/x86.c

+39 −23
Original line number Diff line number Diff line
@@ -7317,35 +7317,21 @@ static bool is_vmware_backdoor_opcode(struct x86_emulate_ctxt *ctxt) 
	return false;

}



int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,

			    int emulation_type, void *insn, int insn_len)

{

	int r;

	struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;

	bool writeback = true;

	bool write_fault_to_spt;



	if (unlikely(!kvm_x86_ops.can_emulate_instruction(vcpu, insn, insn_len)))

		return 1;



	vcpu->arch.l1tf_flush_l1d = true;



/*

	 * Clear write_fault_to_shadow_pgtable here to ensure it is

	 * never reused.

 * Decode to be emulated instruction. Return EMULATION_OK if success.

 */

	write_fault_to_spt = vcpu->arch.write_fault_to_shadow_pgtable;

	vcpu->arch.write_fault_to_shadow_pgtable = false;

	kvm_clear_exception_queue(vcpu);

int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type,

				    void *insn, int insn_len)

{

	int r = EMULATION_OK;

	struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;



	if (!(emulation_type & EMULTYPE_NO_DECODE)) {

	init_emulate_ctxt(vcpu);



	/*

		 * We will reenter on the same instruction since

		 * we do not set complete_userspace_io.  This does not

		 * handle watchpoints yet, those would be handled in

		 * the emulate_ops.

	 * We will reenter on the same instruction since we do not set

	 * complete_userspace_io. This does not handle watchpoints yet,

	 * those would be handled in the emulate_ops.

	 */

	if (!(emulation_type & EMULTYPE_SKIP) &&

	    kvm_vcpu_check_breakpoint(vcpu, &r))
@@ -7362,6 +7348,36 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, 


	trace_kvm_emulate_insn_start(vcpu);

	++vcpu->stat.insn_emulation;



	return r;

}

EXPORT_SYMBOL_GPL(x86_decode_emulated_instruction);



int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,

			    int emulation_type, void *insn, int insn_len)

{

	int r;

	struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;

	bool writeback = true;

	bool write_fault_to_spt;



	if (unlikely(!kvm_x86_ops.can_emulate_instruction(vcpu, insn, insn_len)))

		return 1;



	vcpu->arch.l1tf_flush_l1d = true;



	/*

	 * Clear write_fault_to_shadow_pgtable here to ensure it is

	 * never reused.

	 */

	write_fault_to_spt = vcpu->arch.write_fault_to_shadow_pgtable;

	vcpu->arch.write_fault_to_shadow_pgtable = false;



	if (!(emulation_type & EMULTYPE_NO_DECODE)) {

		kvm_clear_exception_queue(vcpu);



		r = x86_decode_emulated_instruction(vcpu, emulation_type,

						    insn, insn_len);

		if (r != EMULATION_OK)  {

			if ((emulation_type & EMULTYPE_TRAP_UD) ||

			    (emulation_type & EMULTYPE_TRAP_UD_FORCED)) {

arch/x86/kvm/x86.h

+2 −0
Original line number Diff line number Diff line
@@ -273,6 +273,8 @@ bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, 
					  int page_num);

bool kvm_vector_hashing_enabled(void);

void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_code);

int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type,

				    void *insn, int insn_len);

int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,

			    int emulation_type, void *insn, int insn_len);

fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);