On 12.12.14 16:58, Laszlo Ersek wrote:
> The "data_memwidth" property is capable of changing the maximum valid
> access size to the MMIO data register, and (corresponding to the previous
> patch) resizes the memory region similarly, at device realization time.
>
> (Because "data_iomem" is configured and installed dynamically now, we must
> delay those steps to the realize callback.)
>
> The default value of "data_memwidth" is set so that we don't yet diverge
> from "fw_cfg_data_mem_ops".
>
> Most of the fw_cfg users will stick with the default, and for them we
> should continue using the statically allocated "fw_cfg_data_mem_ops". This
> is beneficial for debugging because gdb can resolve pointers referencing
> static objects to the names of those objects.
>
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
> ---
>
> Notes:
> v4:
> - reject I/O port combining if data register is wider than 1 byte
> [Peter]
>
> v3:
> - new in v3 [Drew Jones]
>
> hw/nvram/fw_cfg.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> index eb0ad83..0947136 100644
> --- a/hw/nvram/fw_cfg.c
> +++ b/hw/nvram/fw_cfg.c
> @@ -50,8 +50,9 @@ struct FWCfgState {
> /*< public >*/
>
> MemoryRegion ctl_iomem, data_iomem, comb_iomem;
> uint32_t ctl_iobase, data_iobase;
> + uint32_t data_memwidth;
> FWCfgEntry entries[2][FW_CFG_MAX_ENTRY];
> FWCfgFiles *files;
> uint16_t cur_entry;
> uint32_t cur_offset;
> @@ -569,8 +570,10 @@ FWCfgState *fw_cfg_init(uint32_t ctl_port, uint32_t
> data_port,
>
> dev = qdev_create(NULL, TYPE_FW_CFG);
> qdev_prop_set_uint32(dev, "ctl_iobase", ctl_port);
> qdev_prop_set_uint32(dev, "data_iobase", data_port);
> + qdev_prop_set_uint32(dev, "data_memwidth",
> + fw_cfg_data_mem_ops.valid.max_access_size);
> d = SYS_BUS_DEVICE(dev);
>
> s = FW_CFG(dev);
>
> @@ -607,12 +610,8 @@ static void fw_cfg_initfn(Object *obj)
>
> memory_region_init_io(&s->ctl_iomem, OBJECT(s), &fw_cfg_ctl_mem_ops, s,
> "fwcfg.ctl", FW_CFG_SIZE);
> sysbus_init_mmio(sbd, &s->ctl_iomem);
> - memory_region_init_io(&s->data_iomem, OBJECT(s), &fw_cfg_data_mem_ops, s,
> - "fwcfg.data",
> - fw_cfg_data_mem_ops.valid.max_access_size);
> - sysbus_init_mmio(sbd, &s->data_iomem);
> /* In case ctl and data overlap: */
> memory_region_init_io(&s->comb_iomem, OBJECT(s), &fw_cfg_comb_mem_ops, s,
> "fwcfg", FW_CFG_SIZE);
> }
> @@ -620,19 +619,31 @@ static void fw_cfg_initfn(Object *obj)
> static void fw_cfg_realize(DeviceState *dev, Error **errp)
> {
> FWCfgState *s = FW_CFG(dev);
> SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
> + const MemoryRegionOps *data_mem_ops = &fw_cfg_data_mem_ops;
> uint32_t ctl_io_last;
> uint32_t data_io_end;
>
> + if (s->data_memwidth > data_mem_ops->valid.max_access_size) {
> + MemoryRegionOps *ops;
> +
> + ops = g_memdup(data_mem_ops, sizeof(*data_mem_ops));
Hrm, this memory will leak if the device gets destroyed after realize,
right?
I see 2 options around this:
1) Free it on destruction
2) Add the RegionOps as field into FWCfgState. Then it gets allocated
and free'd automatically
Option 2 is easier (and more failure proof) but will waste a few bytes
of ram for data_memwidth=1 users. I don't think we need to bother about
the few bytes and rather go with safety :).
Alex
