Re: [PATCH] PCI: Exclude VTBAR range from Local MMIOL if necessary

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On 01/13/2010 01:19 PM, Myron Stowe wrote:
> Intel's x58 chipset (IOH) includes a VTBAR (Base Address Register for
> Intel VT-d Chipset Registers) that specifies an 8K aligned system memory
> address for VT-d memory mapped registers.  If BIOS has placed the VT-d
> register window within the Local MMIOL range, it will not be available
> for downstream PCI devices, so remove it from the host bridge's MMIOL
> range.
> 
> This patch determines if the VTBAR is enabled and modifies the IOH's
> Local MMIOL range if it is programmed within such.
> 
> 
> Reference: "Intel X58 Express Chipset Datasheet"
>            http://www.intel.com/Assets/PDF/datasheet/320838.pdf
> 
> 
> Signed-off-by: Myron Stowe <myron.stowe@xxxxxx>
> ---
> 
>  arch/x86/pci/intel_bus.c |   20 +++++++++++++++++++-
>  1 files changed, 19 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/pci/intel_bus.c b/arch/x86/pci/intel_bus.c
> index b7a55dc..f58136c 100644
> --- a/arch/x86/pci/intel_bus.c
> +++ b/arch/x86/pci/intel_bus.c
> @@ -39,13 +39,16 @@ static inline void print_ioh_resources(struct pci_root_info *info)
>  #define IOH_LMMIOH_LIMITU	0x118
>  #define IOH_LCFGBUS		0x11c
>  
> +#define IOH_VTBAR		0x180
> +#define IOH_VTSIZE		0x2000	/* Fixed HW size (not programmable) */
> +
>  static void __devinit pci_root_bus_res(struct pci_dev *dev)
>  {
>  	u16 word;
>  	u32 dword;
>  	struct pci_root_info *info;
>  	u16 io_base, io_end;
> -	u32 mmiol_base, mmiol_end;
> +	u32 mmiol_base, mmiol_end, vtbar;
>  	u64 mmioh_base, mmioh_end;
>  	int bus_base, bus_end;
>  
> @@ -72,6 +75,21 @@ static void __devinit pci_root_bus_res(struct pci_dev *dev)
>  	pci_read_config_dword(dev, IOH_LMMIOL, &dword);
>  	mmiol_base = (dword & 0xff00) << (24 - 8);
>  	mmiol_end = (dword & 0xff000000) | 0xffffff;
> +	pci_read_config_dword(dev, IOH_VTBAR, &dword);
> +	vtbar = dword & 0xfffffffe;
> +	if (dword & 0x1 &&
> +		(mmiol_base < vtbar + IOH_VTSIZE - 1 && vtbar < mmiol_end)) {
> +		/* remove VT-d DRDH from Local MMIOL window */
> +		if (vtbar <= mmiol_base)
> +			mmiol_base = vtbar + IOH_VTSIZE;
> +		else if (mmiol_end <= vtbar + IOH_VTSIZE - 1)
> +			mmiol_end = vtbar;
> +		else {
> +			update_res(info, mmiol_base, vtbar - 1,
> +				   IORESOURCE_MEM, 0);
> +			mmiol_base = vtbar + IOH_VTSIZE;
> +		}
> +	}
>  	update_res(info, mmiol_base, mmiol_end, IORESOURCE_MEM, 0);
>  
>  	pci_read_config_dword(dev, IOH_LMMIOH, &dword);

can you add vt_base and vt_end instead of use + IOH_VTSIZE everywhere?

YH
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