Re: [Qemu-devel] [PATCH RESENT] msix: allow byte and word reading from mmio

[Anthony Liguori]

On 08/19/2010 07:56 AM, Bernhard Kohl wrote:
> It's legal that the guest reads a single byte or word from mmio.
> I have an OS which reads single bytes and it works fine on real
> hardware. Maybe this happens due to casting.
>
> Signed-off-by: Bernhard Kohl<address@hidden>
>    

Hi Michael,

I'm looking for this to come through your tree unless you disagree.

Regards,

Anthony Liguori

> ---
>   hw/msix.c |   20 ++++++++++++++++----
>   1 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/hw/msix.c b/hw/msix.c
> index d99403a..7dac7f7 100644
> --- a/hw/msix.c
> +++ b/hw/msix.c
> @@ -100,10 +100,22 @@ static uint32_t msix_mmio_readl(void *opaque, 
> target_phys_addr_t addr)
>       return pci_get_long(page + offset);
>   }
>
> -static uint32_t msix_mmio_read_unallowed(void *opaque, target_phys_addr_t addr)
> +static uint32_t msix_mmio_readw(void *opaque, target_phys_addr_t addr)
>   {
> -    fprintf(stderr, "MSI-X: only dword read is allowed!\n");
> -    return 0;
> +    PCIDevice *dev = opaque;
> +    unsigned int offset = addr&  (MSIX_PAGE_SIZE - 1)&  ~0x1;
> +    void *page = dev->msix_table_page;
> +
> +    return pci_get_word(page + offset);
> +}
> +
> +static uint32_t msix_mmio_readb(void *opaque, target_phys_addr_t addr)
> +{
> +    PCIDevice *dev = opaque;
> +    unsigned int offset = addr&  (MSIX_PAGE_SIZE - 1);
> +    void *page = dev->msix_table_page;
> +
> +    return pci_get_byte(page + offset);
>   }
>
>   static uint8_t msix_pending_mask(int vector)
> @@ -198,7 +210,7 @@ static CPUWriteMemoryFunc * const msix_mmio_write[] = {
>   };
>
>   static CPUReadMemoryFunc * const msix_mmio_read[] = {
> -    msix_mmio_read_unallowed, msix_mmio_read_unallowed, msix_mmio_readl
> +    msix_mmio_readb, msix_mmio_readw, msix_mmio_readl
>   };
>
>   /* Should be called from device's map method. */
>