[mirror_ubuntu-bionic-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"

static void mmio_write_buf(char *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);
}

static unsigned long mmio_read_buf(char *buf, unsigned int len)
{
	unsigned long data = 0;
	union {
		u16	hword;
		u32	word;
		u64	dword;
	} tmp;

	switch (len) {
	case 1:
		data = buf[0];
		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
 * @vcpu: The VCPU pointer
 * @run:  The VCPU run struct containing the mmio data
 *
 * This should only be called after returning from userspace for MMIO load
 * emulation.
 */
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 = 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_isextabt(vcpu)) {
		/* cache operation on I/O addr, tell guest unsupported */
		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
		return 1;
	}

	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);
		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 (is_write)
		memcpy(run->mmio.data, data_buf, len);

	if (!ret) {
		/* We handled the access successfully in the kernel. */
		vcpu->stat.mmio_exit_kernel++;
		kvm_handle_mmio_return(vcpu, run);
		return 1;
	} else {
		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
6d89d2d9 MZ	26	static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
	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
	58	static unsigned long mmio_read_buf(char *buf, unsigned int len)
	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:
	69	data = buf[0];
	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	/**
	89	* kvm_handle_mmio_return -- Handle MMIO loads after user space emulation
	90	* @vcpu: The VCPU pointer
	91	* @run: The VCPU run struct containing the mmio data
	92	*
	93	* This should only be called after returning from userspace for MMIO load
	94	* emulation.
	95	*/
	96	int kvm_handle_mmio_return(struct kvm_vcpu vcpu, struct kvm_run run)
	97	{
6d89d2d9	98	unsigned long data;
45e96ea6 CD	99	unsigned int len;
	100	int mask;
	101
	102	if (!run->mmio.is_write) {
45e96ea6	103	len = run->mmio.len;
f42798c6	104	if (len > sizeof(unsigned long))
45e96ea6 CD	105	return -EINVAL;
45e96ea6 CD	106
6d89d2d9	107	data = mmio_read_buf(run->mmio.data, len);
45e96ea6	108
f42798c6 MZ	109	if (vcpu->arch.mmio_decode.sign_extend &&
f42798c6 MZ	110	len < sizeof(unsigned long)) {
45e96ea6	111	mask = 1U << ((len * 8) - 1);
6d89d2d9	112	data = (data ^ mask) - mask;
45e96ea6	113	}
6d89d2d9 MZ	114
	115	trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
	116	data);
	117	data = vcpu_data_host_to_guest(vcpu, data, len);
bc45a516	118	vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data);
45e96ea6 CD	119	}
	120
	121	return 0;
	122	}
	123
950324ab	124	static int decode_hsr(struct kvm_vcpu vcpu, bool is_write, int *len)
45e96ea6	125	{
2184a60d	126	unsigned long rt;
950324ab AP	127	int access_size;
950324ab AP	128	bool sign_extend;
45e96ea6	129
78abfcde	130	if (kvm_vcpu_dabt_isextabt(vcpu)) {
45e96ea6	131	/* cache operation on I/O addr, tell guest unsupported */
7393b599	132	kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
45e96ea6 CD	133	return 1;
	134	}
	135
b37670b0	136	if (kvm_vcpu_dabt_iss1tw(vcpu)) {
45e96ea6	137	/* page table accesses IO mem: tell guest to fix its TTBR */
7393b599	138	kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
45e96ea6 CD	139	return 1;
	140	}
	141
950324ab AP	142	access_size = kvm_vcpu_dabt_get_as(vcpu);
	143	if (unlikely(access_size < 0))
	144	return access_size;
45e96ea6	145
950324ab	146	*is_write = kvm_vcpu_dabt_iswrite(vcpu);
7c511b88	147	sign_extend = kvm_vcpu_dabt_issext(vcpu);
d0adf747	148	rt = kvm_vcpu_dabt_get_rd(vcpu);
45e96ea6	149
950324ab	150	*len = access_size;
45e96ea6 CD	151	vcpu->arch.mmio_decode.sign_extend = sign_extend;
	152	vcpu->arch.mmio_decode.rt = rt;
	153
	154	/*
	155	* The MMIO instruction is emulated and should not be re-executed
	156	* in the guest.
	157	*/
23b415d6	158	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
45e96ea6 CD	159	return 0;
	160	}
	161
	162	int io_mem_abort(struct kvm_vcpu vcpu, struct kvm_run run,
	163	phys_addr_t fault_ipa)
	164	{
6d89d2d9	165	unsigned long data;
45e96ea6 CD	166	unsigned long rt;
45e96ea6 CD	167	int ret;
950324ab AP	168	bool is_write;
	169	int len;
	170	u8 data_buf[8];
45e96ea6 CD	171
45e96ea6 CD	172	/*
950324ab AP	173	* Prepare MMIO operation. First decode the syndrome data we get
	174	* from the CPU. Then try if some in-kernel emulation feels
	175	* responsible, otherwise let user space do its magic.
45e96ea6	176	*/
4a1df28a	177	if (kvm_vcpu_dabt_isvalid(vcpu)) {
950324ab	178	ret = decode_hsr(vcpu, &is_write, &len);
45e96ea6 CD	179	if (ret)
	180	return ret;
	181	} else {
	182	kvm_err("load/store instruction decoding not implemented\n");
	183	return -ENOSYS;
	184	}
	185
	186	rt = vcpu->arch.mmio_decode.rt;
6d89d2d9	187
950324ab	188	if (is_write) {
bc45a516 PF	189	data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt),
bc45a516 PF	190	len);
950324ab AP	191
	192	trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data);
	193	mmio_write_buf(data_buf, len, data);
45e96ea6	194
950324ab AP	195	ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len,
950324ab AP	196	data_buf);
5100f983	197	} else {
950324ab	198	trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len,
5100f983	199	fault_ipa, 0);
950324ab AP	200
	201	ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len,
	202	data_buf);
5100f983	203	}
45e96ea6	204
950324ab AP	205	/* Now prepare kvm_run for the potential return to userland. */
	206	run->mmio.is_write = is_write;
	207	run->mmio.phys_addr = fault_ipa;
	208	run->mmio.len = len;
1d6a8212 MZ	209	if (is_write)
1d6a8212 MZ	210	memcpy(run->mmio.data, data_buf, len);
950324ab AP	211
	212	if (!ret) {
	213	/* We handled the access successfully in the kernel. */
b19e6892	214	vcpu->stat.mmio_exit_kernel++;
950324ab	215	kvm_handle_mmio_return(vcpu, run);
1a89dd91	216	return 1;
b19e6892 AT	217	} else {
b19e6892 AT	218	vcpu->stat.mmio_exit_user++;
950324ab	219	}
1a89dd91	220
950324ab	221	run->exit_reason = KVM_EXIT_MMIO;
45e96ea6 CD	222	return 0;
45e96ea6 CD	223	}