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cpu_ioreq_pio, cpu_ioreq_move: introduce read_phys_req_item, write_phys_req_item

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Replace a lot of formulaic multiplications (containing casts, no less)
with calls to a pair of functions.  This encapsulates in a single
place the operations which require care relating to integer overflow.

Cc: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Ian Jackson
2012-12-17 11:43:19 +00:00
committed by Stefano Stabellini
parent f1b8caf1d9
commit a38648290e
1 changed files with 46 additions and 30 deletions
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76
xen-all.c
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@@ -683,11 +683,45 @@ static void do_outp(pio_addr_t addr,
}
}
/*
* Helper functions which read/write an object from/to physical guest
* memory, as part of the implementation of an ioreq.
*
* Equivalent to
* cpu_physical_memory_rw(addr + (req->df ? -1 : +1) * req->size * i,
* val, req->size, 0/1)
* except without the integer overflow problems.
*/
static void rw_phys_req_item(hwaddr addr,
ioreq_t *req, uint32_t i, void *val, int rw)
{
/* Do everything unsigned so overflow just results in a truncated result
* and accesses to undesired parts of guest memory, which is up
* to the guest */
hwaddr offset = (hwaddr)req->size * i;
if (req->df) {
addr -= offset;
} else {
addr += offset;
}
cpu_physical_memory_rw(addr, val, req->size, rw);
}
static inline void read_phys_req_item(hwaddr addr,
ioreq_t *req, uint32_t i, void *val)
{
rw_phys_req_item(addr, req, i, val, 0);
}
static inline void write_phys_req_item(hwaddr addr,
ioreq_t *req, uint32_t i, void *val)
{
rw_phys_req_item(addr, req, i, val, 1);
}
static void cpu_ioreq_pio(ioreq_t *req)
{
int i, sign;
sign = req->df ? -1 : 1;
int i;
if (req->dir == IOREQ_READ) {
if (!req->data_is_ptr) {
@@ -697,9 +731,7 @@ static void cpu_ioreq_pio(ioreq_t *req)
for (i = 0; i < req->count; i++) {
tmp = do_inp(req->addr, req->size);
cpu_physical_memory_write(
req->data + (sign * i * (int64_t)req->size),
(uint8_t *) &tmp, req->size);
write_phys_req_item(req->data, req, i, &tmp);
}
}
} else if (req->dir == IOREQ_WRITE) {
@@ -709,9 +741,7 @@ static void cpu_ioreq_pio(ioreq_t *req)
for (i = 0; i < req->count; i++) {
uint32_t tmp = 0;
cpu_physical_memory_read(
req->data + (sign * i * (int64_t)req->size),
(uint8_t*) &tmp, req->size);
read_phys_req_item(req->data, req, i, &tmp);
do_outp(req->addr, req->size, tmp);
}
}
@@ -720,22 +750,16 @@ static void cpu_ioreq_pio(ioreq_t *req)
static void cpu_ioreq_move(ioreq_t *req)
{
int i, sign;
sign = req->df ? -1 : 1;
int i;
if (!req->data_is_ptr) {
if (req->dir == IOREQ_READ) {
for (i = 0; i < req->count; i++) {
cpu_physical_memory_read(
req->addr + (sign * i * (int64_t)req->size),
(uint8_t *) &req->data, req->size);
read_phys_req_item(req->addr, req, i, &req->data);
}
} else if (req->dir == IOREQ_WRITE) {
for (i = 0; i < req->count; i++) {
cpu_physical_memory_write(
req->addr + (sign * i * (int64_t)req->size),
(uint8_t *) &req->data, req->size);
write_phys_req_item(req->addr, req, i, &req->data);
}
}
} else {
@@ -743,21 +767,13 @@ static void cpu_ioreq_move(ioreq_t *req)
if (req->dir == IOREQ_READ) {
for (i = 0; i < req->count; i++) {
cpu_physical_memory_read(
req->addr + (sign * i * (int64_t)req->size),
(uint8_t*) &tmp, req->size);
cpu_physical_memory_write(
req->data + (sign * i * (int64_t)req->size),
(uint8_t*) &tmp, req->size);
read_phys_req_item(req->addr, req, i, &tmp);
write_phys_req_item(req->data, req, i, &tmp);
}
} else if (req->dir == IOREQ_WRITE) {
for (i = 0; i < req->count; i++) {
cpu_physical_memory_read(
req->data + (sign * i * (int64_t)req->size),
(uint8_t*) &tmp, req->size);
cpu_physical_memory_write(
req->addr + (sign * i * (int64_t)req->size),
(uint8_t*) &tmp, req->size);
read_phys_req_item(req->data, req, i, &tmp);
write_phys_req_item(req->addr, req, i, &tmp);
}
}
}