Re: [Qemu-devel] [PATCH 1/2] Type-safe ioport callbacks

[Blue Swirl]

On Sun, Oct 24, 2010 at 3:34 PM, Avi Kivity <address@hidden> wrote:
> The current ioport callbacks are not type-safe, in that they accept an 
> "opaque"
> pointer as an argument whose type must match the argument to the registration
> function; this is not checked by the compiler.
>
> This patch adds an alternative that is type-safe.  Instead of an opaque
> argument, both registation and the callback use a new IOPort type.  The
> callback then uses container_of() to access its main structures.
>
> Currently the old and new methods exist side by side; once the old way is 
> gone,
> we can also save a bunch of memory since the new method requires one pointer
> per ioport instead of 6.
>
> Signed-off-by: Avi Kivity <address@hidden>

If we are going to change the interface, let's do it so that it's
useful for other uses too:
http://article.gmane.org/gmane.comp.emulators.qemu/76984

> ---
>  ioport.c |   64 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  ioport.h |   16 +++++++++++++++
>  2 files changed, 80 insertions(+), 0 deletions(-)
>
> diff --git a/ioport.c b/ioport.c
> index ec3dc65..47eafc3 100644
> --- a/ioport.c
> +++ b/ioport.c
> @@ -174,6 +174,70 @@ int register_ioport_write(pio_addr_t start, int length, 
> int size,
>     return 0;
>  }
>
> +static uint32_t ioport_readb_thunk(void *opaque, uint32_t addr)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->readb(ioport, addr);
> +}
> +
> +static uint32_t ioport_readw_thunk(void *opaque, uint32_t addr)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->readw(ioport, addr);
> +}
> +
> +static uint32_t ioport_readl_thunk(void *opaque, uint32_t addr)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->readl(ioport, addr);
> +}
> +
> +static void ioport_writeb_thunk(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->writeb(ioport, addr, data);
> +}
> +
> +static void ioport_writew_thunk(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->writew(ioport, addr, data);
> +}
> +
> +static void ioport_writel_thunk(void *opaque, uint32_t addr, uint32_t data)
> +{
> +    IOPort *ioport = opaque;
> +
> +    return ioport->ops->writel(ioport, addr, data);
> +}
> +
> +void ioport_register(IOPort *ioport, pio_addr_t start, pio_addr_t length)
> +{
> +    if (ioport->ops->readb) {
> +        register_ioport_read(start, length, 1, ioport_readb_thunk, ioport);
> +    }
> +    if (ioport->ops->readw) {
> +        register_ioport_read(start, length, 2, ioport_readw_thunk, ioport);
> +    }
> +    if (ioport->ops->readl) {
> +        register_ioport_read(start, length, 4, ioport_readl_thunk, ioport);
> +    }
> +    if (ioport->ops->writeb) {
> +        register_ioport_write(start, length, 1, ioport_writeb_thunk, ioport);
> +    }
> +    if (ioport->ops->writew) {
> +        register_ioport_write(start, length, 2, ioport_writew_thunk, ioport);
> +    }
> +    if (ioport->ops->writel) {
> +        register_ioport_write(start, length, 4, ioport_writel_thunk, ioport);
> +    }
> +}
> +
>  void isa_unassign_ioport(pio_addr_t start, int length)
>  {
>     int i;
> diff --git a/ioport.h b/ioport.h
> index 3d3c8a3..8036e59 100644
> --- a/ioport.h
> +++ b/ioport.h
> @@ -36,6 +36,22 @@ typedef uint32_t pio_addr_t;
>  typedef void (IOPortWriteFunc)(void *opaque, uint32_t address, uint32_t 
> data);
>  typedef uint32_t (IOPortReadFunc)(void *opaque, uint32_t address);
>
> +struct IOPort;
> +
> +typedef struct IOPortOps {
> +    uint32_t (*readb)(struct IOPort *ioport, pio_addr_t addr);
> +    uint32_t (*readw)(struct IOPort *ioport, pio_addr_t addr);
> +    uint32_t (*readl)(struct IOPort *ioport, pio_addr_t addr);
> +    void (*writeb)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
> +    void (*writew)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
> +    void (*writel)(struct IOPort *ioport, pio_addr_t addr, uint32_t data);
> +} IOPortOps;
> +
> +typedef struct IOPort {
> +    IOPortOps *ops;

const