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memory: Introduce DEVICE_HOST_ENDIAN for ram device

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At the moment ram device's memory regions are DEVICE_NATIVE_ENDIAN. It's
incorrect. This memory region is backed by a MMIO area in host, so the
uint64_t data that MemoryRegionOps read from/write to this area should be
host-endian rather than target-endian. Hence, current code does not work
when target and host endianness are different which is the most common case
on PPC64. To fix it, this introduces DEVICE_HOST_ENDIAN for the ram device.

This has been tested on PPC64 BE/LE host/guest in all possible combinations
including TCG.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
Message-Id: <1488171164-28319-1-git-send-email-xyjxie@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Yongji Xie 2017-02-27 12:52:44 +08:00 committed by Paolo Bonzini
parent 11953be792
commit c99a29e702
2 changed files with 7 additions and 1 deletions
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6
include/exec/cpu-common.h
View File

@ -36,6 +36,12 @@ enum device_endian {
DEVICE_LITTLE_ENDIAN,
};
#if defined(HOST_WORDS_BIGENDIAN)
#define DEVICE_HOST_ENDIAN DEVICE_BIG_ENDIAN
#else
#define DEVICE_HOST_ENDIAN DEVICE_LITTLE_ENDIAN
#endif
/* address in the RAM (different from a physical address) */
#if defined(CONFIG_XEN_BACKEND)
typedef uint64_t ram_addr_t;

2
memory.c
View File

@ -1182,7 +1182,7 @@ static void memory_region_ram_device_write(void *opaque, hwaddr addr,
static const MemoryRegionOps ram_device_mem_ops = {
.read = memory_region_ram_device_read,
.write = memory_region_ram_device_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.endianness = DEVICE_HOST_ENDIAN,
.valid = {
.min_access_size = 1,
.max_access_size = 8,