The omap_badwidth_read* and omap_badwidth_write* functions are used by various OMAP devices when the guest makes an access to registers with an invalid width; they do two things: - log a GUEST_ERROR for the access - call cpu_physical_memory_read() or cpu_physical_memory_write() with the offset they are passed in
The first of these produces an unhelpful log message because the function name that is printed is that of the omap-badwidth_* function, not that of the read or write function of the device that called it; this means you can't tell what device is involved. The second is wrong because the offset is an offset into the device but we use it as an absolute physical address, so we will access whatever is at low memory. That happens to be the boot ROM, so we will ignore a write and return random garbage on a read. This bug has been present since 2011, when we did the conversions to the MemoryRegion APIs, which involved changing all devices from working with absolute physical addresses to working with offsets within their MemoryRegions. We must have missed updating these functions. Replace the uses of these functions in omap_i2c.c with an open-coded call to qemu_log_mask() and RAZ/WI behaviour. Signed-off-by: Peter Maydell <[email protected]> --- hw/i2c/omap_i2c.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c index 751bf748fd9..be2b7eb5306 100644 --- a/hw/i2c/omap_i2c.c +++ b/hw/i2c/omap_i2c.c @@ -441,7 +441,9 @@ static uint64_t omap_i2c_readfn(void *opaque, hwaddr addr, case 2: return omap_i2c_read(opaque, addr); default: - return omap_badwidth_read16(opaque, addr); + qemu_log_mask(LOG_GUEST_ERROR, "%s: read at offset 0x%" HWADDR_PRIx + " with bad width %d\n", __func__, addr, size); + return 0; } } @@ -457,7 +459,8 @@ static void omap_i2c_writefn(void *opaque, hwaddr addr, omap_i2c_write(opaque, addr, value); break; default: - omap_badwidth_write16(opaque, addr, value); + qemu_log_mask(LOG_GUEST_ERROR, "%s: write at offset 0x%" HWADDR_PRIx + " with bad width %d\n", __func__, addr, size); break; } } -- 2.43.0
