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Commit ea1bdbf6 authored by James Hogan's avatar James Hogan
Browse files

KVM: MIPS: Update exit handler for VZ 



The general guest exit handler needs a few tweaks for VZ compared to
trap & emulate, which for now are made directly depending on
CONFIG_KVM_MIPS_VZ:

- There is no need to re-enable the hardware page table walker (HTW), as
  it can be left enabled during guest mode operation with VZ.

- There is no need to perform a privilege check, as any guest privilege
  violations should have already been detected by the hardware and
  triggered the appropriate guest exception.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
parent 60c7aa33

arch/mips/kvm/mips.c

+18 −13
Original line number Original line Diff line number Diff line
@@ -1230,6 +1230,7 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) 
	vcpu->mode = OUTSIDE_GUEST_MODE;

	vcpu->mode = OUTSIDE_GUEST_MODE;





	/* re-enable HTW before enabling interrupts */

	/* re-enable HTW before enabling interrupts */

	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ))

		htw_start();

		htw_start();





	/* Set a default exit reason */

	/* Set a default exit reason */
@@ -1248,9 +1249,11 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) 
			cause, opc, run, vcpu);

			cause, opc, run, vcpu);

	trace_kvm_exit(vcpu, exccode);

	trace_kvm_exit(vcpu, exccode);





	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {

		/*

		/*

	 * Do a privilege check, if in UM most of these exit conditions end up

		 * Do a privilege check, if in UM most of these exit conditions

	 * causing an exception to be delivered to the Guest Kernel

		 * end up causing an exception to be delivered to the Guest

		 * Kernel

		 */

		 */

		er = kvm_mips_check_privilege(cause, opc, run, vcpu);

		er = kvm_mips_check_privilege(cause, opc, run, vcpu);

		if (er == EMULATE_PRIV_FAIL) {

		if (er == EMULATE_PRIV_FAIL) {
@@ -1260,6 +1263,7 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) 
			ret = RESUME_HOST;

			ret = RESUME_HOST;

			goto skip_emul;

			goto skip_emul;

		}

		}

	}





	switch (exccode) {

	switch (exccode) {

	case EXCCODE_INT:

	case EXCCODE_INT:
@@ -1418,6 +1422,7 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) 
	}

	}





	/* Disable HTW before returning to guest or host */

	/* Disable HTW before returning to guest or host */

	if (!IS_ENABLED(CONFIG_KVM_MIPS_VZ))

		htw_stop();

		htw_stop();





	return ret;

	return ret;