[mirror_ubuntu-zesty-kernel.git] / arch / arm / kvm / mmio.c

/*
 * 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/kvm_host.h>
#include <asm/kvm_mmio.h>
#include <asm/kvm_emulate.h>
#include <trace/events/kvm.h>

#include "trace.h"

void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data)
{
	void *datap = NULL;
	union {
		u8	byte;
		u16	hword;
		u32	word;
		u64	dword;
	} tmp;

	switch (len) {
	case 1:
		tmp.byte	= data;
		datap		= &tmp.byte;
		break;
	case 2:
		tmp.hword	= data;
		datap		= &tmp.hword;
		break;
	case 4:
		tmp.word	= data;
		datap		= &tmp.word;
		break;
	case 8:
		tmp.dword	= data;
		datap		= &tmp.dword;
		break;
	}

	memcpy(buf, datap, len);
}

unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
{
	unsigned long data = 0;
	union {
		u16	hword;
		u32	word;
		u64	dword;
	} tmp;

	switch (len) {
	case 1:
		data = *(u8 *)buf;
		break;
	case 2:
		memcpy(&tmp.hword, buf, len);
		data = tmp.hword;
		break;
	case 4:
		memcpy(&tmp.word, buf, len);
		data = tmp.word;
		break;
	case 8:
		memcpy(&tmp.dword, buf, len);
		data = tmp.dword;
		break;
	}

	return data;
}

/**
 * kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
 *			     or in-kernel IO emulation
 *
 * @vcpu: The VCPU pointer
 * @run:  The VCPU run struct containing the mmio data
 */
int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
	unsigned long data;
	unsigned int len;
	int mask;

	if (!run->mmio.is_write) {
		len = run->mmio.len;
		if (len > sizeof(unsigned long))
			return -EINVAL;

		data = kvm_mmio_read_buf(run->mmio.data, len);

		if (vcpu->arch.mmio_decode.sign_extend &&
		    len < sizeof(unsigned long)) {
			mask = 1U << ((len * 8) - 1);
			data = (data ^ mask) - mask;
		}

		trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
			       data);
		data = vcpu_data_host_to_guest(vcpu, data, len);
		vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
	}

	return 0;
}

static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len)
{
	unsigned long rt;
	int access_size;
	bool sign_extend;

	if (kvm_vcpu_dabt_iss1tw(vcpu)) {
		/* page table accesses IO mem: tell guest to fix its TTBR */
		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
		return 1;
	}

	access_size = kvm_vcpu_dabt_get_as(vcpu);
	if (unlikely(access_size < 0))
		return access_size;

	*is_write = kvm_vcpu_dabt_iswrite(vcpu);
	sign_extend = kvm_vcpu_dabt_issext(vcpu);
	rt = kvm_vcpu_dabt_get_rd(vcpu);

	*len = access_size;
	vcpu->arch.mmio_decode.sign_extend = sign_extend;
	vcpu->arch.mmio_decode.rt = rt;

	/*
	 * The MMIO instruction is emulated and should not be re-executed
	 * in the guest.
	 */
	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
	return 0;
}

int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
		 phys_addr_t fault_ipa)
{
	unsigned long data;
	unsigned long rt;
	int ret;
	bool is_write;
	int len;
	u8 data_buf[8];

	/*
	 * Prepare MMIO operation. First decode the syndrome data we get
	 * from the CPU. Then try if some in-kernel emulation feels
	 * responsible, otherwise let user space do its magic.
	 */
	if (kvm_vcpu_dabt_isvalid(vcpu)) {
		ret = decode_hsr(vcpu, &is_write, &len);
		if (ret)
			return ret;
	} else {
		kvm_err("load/store instruction decoding not implemented\n");
		return -ENOSYS;
	}

	rt = vcpu->arch.mmio_decode.rt;

	if (is_write) {
		data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
					       len);

		trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data);
		kvm_mmio_write_buf(data_buf, len, data);

		ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len,
				       data_buf);
	} else {
		trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len,
			       fault_ipa, 0);

		ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len,
				      data_buf);
	}

	/* Now prepare kvm_run for the potential return to userland. */
	run->mmio.is_write	= is_write;
	run->mmio.phys_addr	= fault_ipa;
	run->mmio.len		= len;

	if (!ret) {
		/* We handled the access successfully in the kernel. */
		if (!is_write)
			memcpy(run->mmio.data, data_buf, len);
		vcpu->stat.mmio_exit_kernel++;
		kvm_handle_mmio_return(vcpu, run);
		return 1;
	}

	if (is_write)
		memcpy(run->mmio.data, data_buf, len);
	vcpu->stat.mmio_exit_user++;
	run->exit_reason	= KVM_EXIT_MMIO;
	return 0;
}
Commit	Line	Data
45e96ea6 CD	1	/*
	2	* Copyright (C) 2012 - Virtual Open Systems and Columbia University
	3	* Author: Christoffer Dall <c.dall@virtualopensystems.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2, as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	17	*/
	18
	19	#include <linux/kvm_host.h>
	20	#include <asm/kvm_mmio.h>
	21	#include <asm/kvm_emulate.h>
	22	#include <trace/events/kvm.h>
	23
	24	#include "trace.h"
	25
d5a5a0ef	26	void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data)
6d89d2d9 MZ	27	{
	28	void *datap = NULL;
	29	union {
	30	u8 byte;
	31	u16 hword;
	32	u32 word;
	33	u64 dword;
	34	} tmp;
	35
	36	switch (len) {
	37	case 1:
	38	tmp.byte = data;
	39	datap = &tmp.byte;
	40	break;
	41	case 2:
	42	tmp.hword = data;
	43	datap = &tmp.hword;
	44	break;
	45	case 4:
	46	tmp.word = data;
	47	datap = &tmp.word;
	48	break;
	49	case 8:
	50	tmp.dword = data;
	51	datap = &tmp.dword;
	52	break;
	53	}
	54
	55	memcpy(buf, datap, len);
	56	}
	57
d5a5a0ef	58	unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
6d89d2d9 MZ	59	{
	60	unsigned long data = 0;
	61	union {
	62	u16 hword;
	63	u32 word;
	64	u64 dword;
	65	} tmp;
	66
	67	switch (len) {
	68	case 1:
d5a5a0ef	69	data = (u8 )buf;
6d89d2d9 MZ	70	break;
	71	case 2:
	72	memcpy(&tmp.hword, buf, len);
	73	data = tmp.hword;
	74	break;
	75	case 4:
	76	memcpy(&tmp.word, buf, len);
	77	data = tmp.word;
	78	break;
	79	case 8:
	80	memcpy(&tmp.dword, buf, len);
	81	data = tmp.dword;
	82	break;
	83	}
	84
	85	return data;
	86	}
	87
45e96ea6 CD	88	/**
45e96ea6 CD	89	* kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
83091db9 CD	90	* or in-kernel IO emulation
83091db9 CD	91	*
45e96ea6 CD	92	* @vcpu: The VCPU pointer
45e96ea6 CD	93	* @run: The VCPU run struct containing the mmio data
45e96ea6 CD	94	*/
	95	int kvm_handle_mmio_return(struct kvm_vcpu vcpu, struct kvm_run run)
	96	{
6d89d2d9	97	unsigned long data;
45e96ea6 CD	98	unsigned int len;
	99	int mask;
	100
	101	if (!run->mmio.is_write) {
45e96ea6	102	len = run->mmio.len;
f42798c6	103	if (len > sizeof(unsigned long))
45e96ea6 CD	104	return -EINVAL;
45e96ea6 CD	105
d5a5a0ef	106	data = kvm_mmio_read_buf(run->mmio.data, len);
45e96ea6	107
f42798c6 MZ	108	if (vcpu->arch.mmio_decode.sign_extend &&
f42798c6 MZ	109	len < sizeof(unsigned long)) {
45e96ea6	110	mask = 1U << ((len * 8) - 1);
6d89d2d9	111	data = (data ^ mask) - mask;
45e96ea6	112	}
6d89d2d9 MZ	113
	114	trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
	115	data);
	116	data = vcpu_data_host_to_guest(vcpu, data, len);
bc45a516	117	vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
45e96ea6 CD	118	}
	119
	120	return 0;
	121	}
	122
950324ab	123	static int decode_hsr(struct kvm_vcpu vcpu, bool is_write, int *len)
45e96ea6	124	{
2184a60d	125	unsigned long rt;
950324ab AP	126	int access_size;
950324ab AP	127	bool sign_extend;
45e96ea6	128
b37670b0	129	if (kvm_vcpu_dabt_iss1tw(vcpu)) {
45e96ea6	130	/* page table accesses IO mem: tell guest to fix its TTBR */
7393b599	131	kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
45e96ea6 CD	132	return 1;
	133	}
	134
950324ab AP	135	access_size = kvm_vcpu_dabt_get_as(vcpu);
	136	if (unlikely(access_size < 0))
	137	return access_size;
45e96ea6	138
950324ab	139	*is_write = kvm_vcpu_dabt_iswrite(vcpu);
7c511b88	140	sign_extend = kvm_vcpu_dabt_issext(vcpu);
d0adf747	141	rt = kvm_vcpu_dabt_get_rd(vcpu);
45e96ea6	142
950324ab	143	*len = access_size;
45e96ea6 CD	144	vcpu->arch.mmio_decode.sign_extend = sign_extend;
	145	vcpu->arch.mmio_decode.rt = rt;
	146
	147	/*
	148	* The MMIO instruction is emulated and should not be re-executed
	149	* in the guest.
	150	*/
23b415d6	151	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
45e96ea6 CD	152	return 0;
	153	}
	154
	155	int io_mem_abort(struct kvm_vcpu vcpu, struct kvm_run run,
	156	phys_addr_t fault_ipa)
	157	{
6d89d2d9	158	unsigned long data;
45e96ea6 CD	159	unsigned long rt;
45e96ea6 CD	160	int ret;
950324ab AP	161	bool is_write;
	162	int len;
	163	u8 data_buf[8];
45e96ea6 CD	164
45e96ea6 CD	165	/*
950324ab AP	166	* Prepare MMIO operation. First decode the syndrome data we get
	167	* from the CPU. Then try if some in-kernel emulation feels
	168	* responsible, otherwise let user space do its magic.
45e96ea6	169	*/
4a1df28a	170	if (kvm_vcpu_dabt_isvalid(vcpu)) {
950324ab	171	ret = decode_hsr(vcpu, &is_write, &len);
45e96ea6 CD	172	if (ret)
	173	return ret;
	174	} else {
	175	kvm_err("load/store instruction decoding not implemented\n");
	176	return -ENOSYS;
	177	}
	178
	179	rt = vcpu->arch.mmio_decode.rt;
6d89d2d9	180
950324ab	181	if (is_write) {
bc45a516 PF	182	data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
bc45a516 PF	183	len);
950324ab AP	184
950324ab AP	185	trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data);
d5a5a0ef	186	kvm_mmio_write_buf(data_buf, len, data);
45e96ea6	187
950324ab AP	188	ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len,
950324ab AP	189	data_buf);
5100f983	190	} else {
950324ab	191	trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len,
5100f983	192	fault_ipa, 0);
950324ab AP	193
	194	ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len,
	195	data_buf);
5100f983	196	}
45e96ea6	197
950324ab AP	198	/* Now prepare kvm_run for the potential return to userland. */
	199	run->mmio.is_write = is_write;
	200	run->mmio.phys_addr = fault_ipa;
	201	run->mmio.len = len;
950324ab AP	202
	203	if (!ret) {
	204	/* We handled the access successfully in the kernel. */
83091db9 CD	205	if (!is_write)
83091db9 CD	206	memcpy(run->mmio.data, data_buf, len);
b19e6892	207	vcpu->stat.mmio_exit_kernel++;
950324ab	208	kvm_handle_mmio_return(vcpu, run);
1a89dd91	209	return 1;
950324ab	210	}
1a89dd91	211
83091db9 CD	212	if (is_write)
	213	memcpy(run->mmio.data, data_buf, len);
	214	vcpu->stat.mmio_exit_user++;
950324ab	215	run->exit_reason = KVM_EXIT_MMIO;
45e96ea6 CD	216	return 0;
45e96ea6 CD	217	}