From 23f5b17a0877f79d660019e2aef34ec19cbc906b Mon Sep 17 00:00:00 2001 From: Yongji Xie Date: Fri, 2 Mar 2018 11:24:12 -0500 Subject: [PATCH] memory: Introduce DEVICE_HOST_ENDIAN for ram device 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. Backports commit c99a29e702528698c0ce2590f06ca7ff239f7c39 from qemu --- qemu/include/exec/cpu-common.h | 6 ++++++ qemu/memory.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/qemu/include/exec/cpu-common.h b/qemu/include/exec/cpu-common.h index 8424f11d..1b5d3c45 100644 --- a/qemu/include/exec/cpu-common.h +++ b/qemu/include/exec/cpu-common.h @@ -22,6 +22,12 @@ 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; diff --git a/qemu/memory.c b/qemu/memory.c index f0874a27..f7128f5b 100644 --- a/qemu/memory.c +++ b/qemu/memory.c @@ -1064,7 +1064,7 @@ static const MemoryRegionOps ram_device_mem_ops = { memory_region_ram_device_write, NULL, NULL, - DEVICE_NATIVE_ENDIAN, + DEVICE_HOST_ENDIAN, // valid { 1, 8,