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Re: [Qemu-devel] [PATCH] Enable 8-byte wide MMIO for 16550 serial device
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [PATCH] Enable 8-byte wide MMIO for 16550 serial devices |
Date: |
Thu, 2 Nov 2017 16:28:09 -0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
Hi Mike, Paolo.
>> diff --git a/hw/char/serial.c b/hw/char/serial.c
>> index 376bd2f240..c16c19a406 100644
>> --- a/hw/char/serial.c
>> +++ b/hw/char/serial.c
>> @@ -1005,7 +1005,7 @@ static void serial_mm_write(void *opaque, hwaddr addr,
>> uint64_t value, unsigned size)
>> {
>> SerialState *s = opaque;
>> - value &= ~0u >> (32 - (size * 8));
>> + value &= ~((uint64_t)0) >> (64 - (size * 8));
>> serial_ioport_write(s, addr >> s->it_shift, value, 1);
>> }
>
> Couldn't this be simply "value &= 255"? Otherwise looks good.
This is not incorrect, but I don't think this is the correct fix.
Isn't it what memory::access_with_adjusted_size() is supposed to do with
.impl.max_access_size = 1?
This looks like the same issue I tried to fix here:
http://lists.nongnu.org/archive/html/qemu-devel/2017-08/msg02255.html
I'll try to find some time to respin the full series with tests.
>> @@ -1014,16 +1014,22 @@ static const MemoryRegionOps serial_mm_ops[3] = {
>> .read = serial_mm_read,
>> .write = serial_mm_write,
>> .endianness = DEVICE_NATIVE_ENDIAN,
>> + .valid.max_access_size = 8,
>> + .impl.max_access_size = 8,
>> },
>> [DEVICE_LITTLE_ENDIAN] = {
>> .read = serial_mm_read,
>> .write = serial_mm_write,
>> .endianness = DEVICE_LITTLE_ENDIAN,
>> + .valid.max_access_size = 8,
>> + .impl.max_access_size = 8,
>> },
>> [DEVICE_BIG_ENDIAN] = {
>> .read = serial_mm_read,
>> .write = serial_mm_write,
>> .endianness = DEVICE_BIG_ENDIAN,
>> + .valid.max_access_size = 8,
>> + .impl.max_access_size = 8,