ARM: KVM: Add HYP mode entry code

obj-$(CONFIG_KVM_ARM_HOST) += vfp.o

obj-$(CONFIG_KVM_ARM_HOST) += banked-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += entry.o

obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry.o

obj-$(CONFIG_KVM_ARM_HOST) += switch.o

/*

 * Copyright (C) 2012 - Virtual Open Systems and Columbia University

 * Author: Christoffer Dall <c.dall@virtualopensystems.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License, version 2, as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */

#include <linux/linkage.h>

#include <asm/kvm_arm.h>

#include <asm/kvm_asm.h>

	.arch_extension     virt

	.text

	.pushsection	.hyp.text, "ax"

.macro load_vcpu	reg

	mrc	p15, 4, \reg, c13, c0, 2	@ HTPIDR

.endm

/********************************************************************

 * Hypervisor exception vector and handlers

 *

 *

 * The KVM/ARM Hypervisor ABI is defined as follows:

 *

 * Entry to Hyp mode from the host kernel will happen _only_ when an HVC

 * instruction is issued since all traps are disabled when running the host

 * kernel as per the Hyp-mode initialization at boot time.

 *

 * HVC instructions cause a trap to the vector page + offset 0x14 (see hyp_hvc

 * below) when the HVC instruction is called from SVC mode (i.e. a guest or the

 * host kernel) and they cause a trap to the vector page + offset 0x8 when HVC

 * instructions are called from within Hyp-mode.

 *

 * Hyp-ABI: Calling HYP-mode functions from host (in SVC mode):

 *    Switching to Hyp mode is done through a simple HVC #0 instruction. The

 *    exception vector code will check that the HVC comes from VMID==0.

 *    - r0 contains a pointer to a HYP function

 *    - r1, r2, and r3 contain arguments to the above function.

 *    - The HYP function will be called with its arguments in r0, r1 and r2.

 *    On HYP function return, we return directly to SVC.

 *

 * Note that the above is used to execute code in Hyp-mode from a host-kernel

 * point of view, and is a different concept from performing a world-switch and

 * executing guest code SVC mode (with a VMID != 0).

 */

	.align 5

__hyp_vector:

	.global	__hyp_vector

__kvm_hyp_vector:

	.weak __kvm_hyp_vector

	@ Hyp-mode exception vector

	W(b)	hyp_reset

	W(b)	hyp_undef

	W(b)	hyp_svc

	W(b)	hyp_pabt

	W(b)	hyp_dabt

	W(b)	hyp_hvc

	W(b)	hyp_irq

	W(b)	hyp_fiq

.macro invalid_vector label, cause

	.align

\label:	b	.

.endm

	invalid_vector	hyp_reset

	invalid_vector	hyp_undef

	invalid_vector	hyp_svc

	invalid_vector	hyp_pabt

	invalid_vector	hyp_dabt

	invalid_vector	hyp_fiq

hyp_hvc:

	/*

	 * Getting here is either because of a trap from a guest,

	 * or from executing HVC from the host kernel, which means

	 * "do something in Hyp mode".

	 */

	push	{r0, r1, r2}

	@ Check syndrome register

	mrc	p15, 4, r1, c5, c2, 0	@ HSR

	lsr	r0, r1, #HSR_EC_SHIFT

	cmp	r0, #HSR_EC_HVC

	bne	guest_trap		@ Not HVC instr.

	/*

	 * Let's check if the HVC came from VMID 0 and allow simple

	 * switch to Hyp mode

	 */

	mrrc    p15, 6, r0, r2, c2

	lsr     r2, r2, #16

	and     r2, r2, #0xff

	cmp     r2, #0

	bne	guest_trap		@ Guest called HVC

	/*

	 * Getting here means host called HVC, we shift parameters and branch

	 * to Hyp function.

	 */

	pop	{r0, r1, r2}

	/* Check for __hyp_get_vectors */

	cmp	r0, #-1

	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR

	beq	1f

	push	{lr}

	mov	lr, r0

	mov	r0, r1

	mov	r1, r2

	mov	r2, r3

THUMB(	orr	lr, #1)

	blx	lr			@ Call the HYP function

	pop	{lr}

1:	eret

guest_trap:

	load_vcpu r0			@ Load VCPU pointer to r0

#ifdef CONFIG_VFPv3

	@ Check for a VFP access

	lsr	r1, r1, #HSR_EC_SHIFT

	cmp	r1, #HSR_EC_CP_0_13

	beq	__vfp_guest_restore

#endif

	mov	r1, #ARM_EXCEPTION_HVC

	b	__guest_exit

hyp_irq:

	push	{r0, r1, r2}

	mov	r1, #ARM_EXCEPTION_IRQ

	load_vcpu r0			@ Load VCPU pointer to r0

	b	__guest_exit

	.ltorg

	.popsection

int asmlinkage __guest_enter(struct kvm_vcpu *vcpu,

			     struct kvm_cpu_context *host);

int asmlinkage __hyp_do_panic(const char *, int, u32);

#endif /* __ARM_KVM_HYP_H__ */