Re: [Qemu-devel] [PATCH] intel_iommu: fix VTD_SID_TO_BUS

[Markus Armbruster]

"Michael S. Tsirkin" <address@hidden> writes:

> (((sid) >> 8) && 0xff)  makes no sense
> (((sid) >> 8) & 0xff) seems to be what was meant.
>
> Suggested-by: Markus Armbruster <address@hidden>

Actually by the reporter of https://bugs.launchpad.net/bugs/1382477

> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>
> Compile-tested only.
>
>  include/hw/i386/intel_iommu.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index f4701e1..e321ee4 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -37,7 +37,7 @@
>  #define VTD_PCI_DEVFN_MAX           256
>  #define VTD_PCI_SLOT(devfn)         (((devfn) >> 3) & 0x1f)
>  #define VTD_PCI_FUNC(devfn)         ((devfn) & 0x07)
> -#define VTD_SID_TO_BUS(sid)         (((sid) >> 8) && 0xff)
> +#define VTD_SID_TO_BUS(sid)         (((sid) >> 8) & 0xff)
>  #define VTD_SID_TO_DEVFN(sid)       ((sid) & 0xff)
>  
>  #define DMAR_REG_SIZE               0x230

Can't find the spec right now, but it looks plausible enough.

Only use is in vtd_context_device_invalidate().  Bug's impact isn't
obvious to me.

Reviewed-by: Markus Armbruster <address@hidden>