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exec/ioport: Resolve redundant .base attribute in struct MemoryRegionPortio

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portio_list_add_1() creates a MemoryRegionPortioList instance which holds a
MemoryRegion `mr` and an array of MemoryRegionPortio elements named `ports`.
Each element in the array gets assigned the same value for its .base attribute.
The same value also ends up as the .addr attribute of `mr` due to the
memory_region_add_subregion() call. This means that all .base attributes are
the same as `mr.addr`.

The only usages of MemoryRegionPortio::base were in portio_read() and
portio_write(). Both functions get above MemoryRegionPortioList as their
opaque parameter. In both cases find_portio() can only return one of the
MemoryRegionPortio elements of the `ports` array. Due to above observation any
element will have the same .base value equal to `mr.addr` which is also
accessible.

Hence, `mrpio->mr.addr` is equivalent to `mrp->base` and
MemoryRegionPortio::base is redundant and can be removed.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-Id: <20240114123911.4877-5-shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Bernhard Beschow 2024-01-14 13:39:04 +01:00 committed by Michael S. Tsirkin
parent ee3d1f1b46
commit 4edee342f8
2 changed files with 6 additions and 8 deletions
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1
include/exec/ioport.h
View File

@ -35,7 +35,6 @@ typedef struct MemoryRegionPortio {
unsigned size;
uint32_t (*read)(void *opaque, uint32_t address);
void (*write)(void *opaque, uint32_t address, uint32_t data);
uint32_t base; /* private field */
} MemoryRegionPortio;
#define PORTIO_END_OF_LIST() { }

13
system/ioport.c
View File

@ -181,13 +181,13 @@ static uint64_t portio_read(void *opaque, hwaddr addr, unsigned size)
data = ((uint64_t)1 << (size * 8)) - 1;
if (mrp) {
data = mrp->read(mrpio->portio_opaque, mrp->base + addr);
data = mrp->read(mrpio->portio_opaque, mrpio->mr.addr + addr);
} else if (size == 2) {
mrp = find_portio(mrpio, addr, 1, false);
if (mrp) {
data = mrp->read(mrpio->portio_opaque, mrp->base + addr);
data = mrp->read(mrpio->portio_opaque, mrpio->mr.addr + addr);
if (addr + 1 < mrp->offset + mrp->len) {
data |= mrp->read(mrpio->portio_opaque, mrp->base + addr + 1) << 8;
data |= mrp->read(mrpio->portio_opaque, mrpio->mr.addr + addr + 1) << 8;
} else {
data |= 0xff00;
}
@ -203,13 +203,13 @@ static void portio_write(void *opaque, hwaddr addr, uint64_t data,
const MemoryRegionPortio *mrp = find_portio(mrpio, addr, size, true);
if (mrp) {
mrp->write(mrpio->portio_opaque, mrp->base + addr, data);
mrp->write(mrpio->portio_opaque, mrpio->mr.addr + addr, data);
} else if (size == 2) {
mrp = find_portio(mrpio, addr, 1, true);
if (mrp) {
mrp->write(mrpio->portio_opaque, mrp->base + addr, data & 0xff);
mrp->write(mrpio->portio_opaque, mrpio->mr.addr + addr, data & 0xff);
if (addr + 1 < mrp->offset + mrp->len) {
mrp->write(mrpio->portio_opaque, mrp->base + addr + 1, data >> 8);
mrp->write(mrpio->portio_opaque, mrpio->mr.addr + addr + 1, data >> 8);
}
}
}
@ -244,7 +244,6 @@ static void portio_list_add_1(PortioList *piolist,
/* Adjust the offsets to all be zero-based for the region. */
for (i = 0; i < count; ++i) {
mrpio->ports[i].offset -= off_low;
mrpio->ports[i].base = start + off_low;
}
/*