From 4edee342f81397e8938ba7a80d1908c5103b66c8 Mon Sep 17 00:00:00 2001
From: Bernhard Beschow <shentey@gmail.com>
Date: Sun, 14 Jan 2024 13:39:04 +0100
Subject: exec/ioport: Resolve redundant .base attribute in struct
MemoryRegionPortio
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>
---
include/exec/ioport.h | 1 -
1 file changed, 1 deletion(-)
(limited to 'include')
diff --git a/include/exec/ioport.h b/include/exec/ioport.h
index e34f668998..95f1dc30d0 100644
--- a/include/exec/ioport.h
+++ b/include/exec/ioport.h
@@ -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() { }
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