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/*
* Copyright (C) 2012 ARM Ltd.
* Author: Marc Zyngier <marc.zyngier@arm.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, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <asm/kvm_emulate.h>
#define ACCESS_READ_VALUE (1 << 0)
#define ACCESS_READ_RAZ (0 << 0)
#define ACCESS_READ_MASK(x) ((x) & (1 << 0))
#define ACCESS_WRITE_IGNORED (0 << 1)
#define ACCESS_WRITE_SETBIT (1 << 1)
#define ACCESS_WRITE_CLEARBIT (2 << 1)
#define ACCESS_WRITE_VALUE (3 << 1)
#define ACCESS_WRITE_MASK(x) ((x) & (3 << 1))
static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask)
{
return *((u32 *)mmio->data) & mask;
}
static void mmio_data_write(struct kvm_exit_mmio *mmio, u32 mask, u32 value)
{
*((u32 *)mmio->data) = value & mask;
}
/**
* vgic_reg_access - access vgic register
* @mmio: pointer to the data describing the mmio access
* @reg: pointer to the virtual backing of vgic distributor data
* @offset: least significant 2 bits used for word offset
* @mode: ACCESS_ mode (see defines above)
*
* Helper to make vgic register access easier using one of the access
* modes defined for vgic register access
* (read,raz,write-ignored,setbit,clearbit,write)
*/
static void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
phys_addr_t offset, int mode)
{
int word_offset = (offset & 3) * 8;
u32 mask = (1UL << (mmio->len * 8)) - 1;
u32 regval;
/*
* Any alignment fault should have been delivered to the guest
* directly (ARM ARM B3.12.7 "Prioritization of aborts").
*/
if (reg) {
regval = *reg;
} else {
BUG_ON(mode != (ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED));
regval = 0;
}
if (mmio->is_write) {
u32 data = mmio_data_read(mmio, mask) << word_offset;
switch (ACCESS_WRITE_MASK(mode)) {
case ACCESS_WRITE_IGNORED:
return;
case ACCESS_WRITE_SETBIT:
regval |= data;
break;
case ACCESS_WRITE_CLEARBIT:
regval &= ~data;
break;
case ACCESS_WRITE_VALUE:
regval = (regval & ~(mask << word_offset)) | data;
break;
}
*reg = regval;
} else {
switch (ACCESS_READ_MASK(mode)) {
case ACCESS_READ_RAZ:
regval = 0;
/* fall through */
case ACCESS_READ_VALUE:
mmio_data_write(mmio, mask, regval >> word_offset);
}
}
}
/*
* I would have liked to use the kvm_bus_io_*() API instead, but it
* cannot cope with banked registers (only the VM pointer is passed
* around, and we need the vcpu). One of these days, someone please
* fix it!
*/
struct mmio_range {
phys_addr_t base;
unsigned long len;
bool (*handle_mmio)(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
phys_addr_t offset);
};
static const struct mmio_range vgic_ranges[] = {
{}
};
static const
struct mmio_range *find_matching_range(const struct mmio_range *ranges,
struct kvm_exit_mmio *mmio,
phys_addr_t base)
{
const struct mmio_range *r = ranges;
phys_addr_t addr = mmio->phys_addr - base;
while (r->len) {
if (addr >= r->base &&
(addr + mmio->len) <= (r->base + r->len))
return r;
r++;
}
return NULL;
}
/**
* vgic_handle_mmio - handle an in-kernel MMIO access
* @vcpu: pointer to the vcpu performing the access
* @run: pointer to the kvm_run structure
* @mmio: pointer to the data describing the access
*
* returns true if the MMIO access has been performed in kernel space,
* and false if it needs to be emulated in user space.
*/
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
struct kvm_exit_mmio *mmio)
{
return KVM_EXIT_MMIO;
}
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