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[Qemu-devel] [PATCH 3/4] exec: Support 64-bit operations in address_spac
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 3/4] exec: Support 64-bit operations in address_space_rw |
Date: |
Mon, 8 Jul 2013 18:01:11 -0700 |
Honor the implementation maximum access size, and at least check
the minimum access size.
Signed-off-by: Richard Henderson <address@hidden>
---
exec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 56 insertions(+), 12 deletions(-)
diff --git a/exec.c b/exec.c
index 03fdf7e..5da22dc 100644
--- a/exec.c
+++ b/exec.c
@@ -1902,15 +1902,37 @@ static inline bool memory_access_is_direct(MemoryRegion
*mr, bool is_write)
return false;
}
-static inline int memory_access_size(MemoryRegion *mr, int l, hwaddr addr)
+static int memory_access_size(MemoryRegion *mr, unsigned l, hwaddr addr)
{
- if (l >= 4 && (((addr & 3) == 0 || mr->ops->impl.unaligned))) {
- return 4;
+ unsigned access_size_min = mr->ops->impl.min_access_size;
+ unsigned access_size_max = mr->ops->impl.max_access_size;
+
+ /* Regions are assumed to support 1-4 byte accesses unless
+ otherwise specified. */
+ if (access_size_min == 0) {
+ access_size_min = 1;
+ }
+ if (access_size_max == 0) {
+ access_size_max = 4;
+ }
+
+ /* Bound the maximum access by the alignment of the address. */
+ if (!mr->ops->impl.unaligned) {
+ unsigned align_size_max = addr & -addr;
+ if (align_size_max != 0 && align_size_max < access_size_max) {
+ access_size_max = align_size_max;
+ }
}
- if (l >= 2 && (((addr & 1) == 0) || mr->ops->impl.unaligned)) {
- return 2;
+
+ /* Don't attempt accesses larger than the maximum. */
+ if (l > access_size_max) {
+ l = access_size_max;
}
- return 1;
+ /* ??? The users of this function are wrong, not supporting minimums larger
+ than the remaining length. C.f. memory.c:access_with_adjusted_size. */
+ assert(l >= access_size_min);
+
+ return l;
}
bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
@@ -1932,18 +1954,29 @@ bool address_space_rw(AddressSpace *as, hwaddr addr,
uint8_t *buf,
l = memory_access_size(mr, l, addr1);
/* XXX: could force cpu_single_env to NULL to avoid
potential bugs */
- if (l == 4) {
+ switch (l) {
+ case 8:
+ /* 64 bit write access */
+ val = ldq_p(buf);
+ error |= io_mem_write(mr, addr1, val, 8);
+ break;
+ case 4:
/* 32 bit write access */
val = ldl_p(buf);
error |= io_mem_write(mr, addr1, val, 4);
- } else if (l == 2) {
+ break;
+ case 2:
/* 16 bit write access */
val = lduw_p(buf);
error |= io_mem_write(mr, addr1, val, 2);
- } else {
+ break;
+ case 1:
/* 8 bit write access */
val = ldub_p(buf);
error |= io_mem_write(mr, addr1, val, 1);
+ break;
+ default:
+ abort();
}
} else {
addr1 += memory_region_get_ram_addr(mr);
@@ -1956,18 +1989,29 @@ bool address_space_rw(AddressSpace *as, hwaddr addr,
uint8_t *buf,
if (!memory_access_is_direct(mr, is_write)) {
/* I/O case */
l = memory_access_size(mr, l, addr1);
- if (l == 4) {
+ switch (l) {
+ case 8:
+ /* 64 bit read access */
+ error |= io_mem_read(mr, addr1, &val, 8);
+ stq_p(buf, val);
+ break;
+ case 4:
/* 32 bit read access */
error |= io_mem_read(mr, addr1, &val, 4);
stl_p(buf, val);
- } else if (l == 2) {
+ break;
+ case 2:
/* 16 bit read access */
error |= io_mem_read(mr, addr1, &val, 2);
stw_p(buf, val);
- } else {
+ break;
+ case 1:
/* 8 bit read access */
error |= io_mem_read(mr, addr1, &val, 1);
stb_p(buf, val);
+ break;
+ default:
+ abort();
}
} else {
/* RAM case */
--
1.8.1.4