Re: [Xen-devel] [PATCH] hw/piix4acpi: Make writes to ACPI_DBG_IO_ADDR actually work.

[Ross Philipson <ross.philipson@xxxxxxxxxx>]

On 11/11/2013 01:42 PM, Konrad Rzeszutek Wilk wrote:
> The ACPI AML code has little snippets where it uses two
> memory locations to stash debug information when doing PCI
> hotplug, such as:
>
> Device (S20)
> {
>      Name (_ADR, 0x00040000)
>      Name (_SUN, 0x04)
>      Method (_EJ0, 1, NotSerialized)
>      {
>         Store (0x20, \_GPE.DPT1)
>         Store (0x88, \_GPE.DPT2)
>         Store (One, \_GPE.PH20)
>      }
>
>      Method (_STA, 0, NotSerialized)
>      {
>         Store (0x20, \_GPE.DPT1)
>         Store (0x89, \_GPE.DPT2)
>      }
> }
>
> and DPT1 (and DPT2) is defined as:
>
> OperationRegion ( DG1, SystemIO, 0xb044, 0x04 )
> Field ( DG1, ByteAcc, NoLock, Preserve ) {
>      DPT1, 8, DPT2, 8
> }
Just as a note for the sake of correctness, that Field only defines 2 
bytes but the OpRegion is defined as 4 bytes (and doesn't need to be).
> But unfortunately when we do the writes they are done
> as byte writes, not as 4-byte writes (long). Hence
> any debug values are never show in QEMU.
>
> This fixes it so that we can see them in the log file.
>
> CC: ian.jackson@xxxxxxxxxxxxx
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
>   hw/piix4acpi.c |    4 ++--
>   1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/piix4acpi.c b/hw/piix4acpi.c
> index bf916d9..ddbe8e0 100644
> --- a/hw/piix4acpi.c
> +++ b/hw/piix4acpi.c
> @@ -284,7 +284,7 @@ static inline void clear_bit(uint8_t *map, int bit)
>       map[bit / 8] &= ~(1 << (bit % 8));
>   }
>
> -static void acpi_dbg_writel(void *opaque, uint32_t addr, uint32_t val)
> +static void acpi_dbg_writeb(void *opaque, uint32_t addr, uint32_t val)
>   {
>       PIIX4ACPI_LOG(PIIX4ACPI_LOG_DEBUG, "ACPI: DBG: 0x%08x\n", val);
>       PIIX4ACPI_LOG(PIIX4ACPI_LOG_INFO, "ACPI:debug: write addr=0x%x, 
> val=0x%x.\n", addr, val);
> @@ -776,7 +776,7 @@ i2c_bus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t 
> smb_io_base,
>   #ifdef CONFIG_PASSTHROUGH
>       php_devfn_init();
>   #endif
> -    register_ioport_write(ACPI_DBG_IO_ADDR, 4, 4, acpi_dbg_writel, d);
> +    register_ioport_write(ACPI_DBG_IO_ADDR, 4, 1, acpi_dbg_writeb, d);
>
>       register_savevm("piix4acpi", 0, 2, piix4acpi_save, piix4acpi_load, d);

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