Re: [PATCH v3 1/2] PCI: vmd: Filter resource type bits from shadow register

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Wed, May 27, 2020 at 11:02:39PM -0400, Jon Derrick wrote:
> Versions of VMD with the Host Physical Address shadow register use this
> register to calculate the bus address offset needed to do guest
> passthrough of the domain. This register shadows the Host Physical
> Address registers including the resource type bits. After calculating
> the offset, the extra resource type bits lead to the VMD resources being
> over-provisioned at the front and under-provisioned at the back.
> 
> Example:
> pci 10000:80:02.0: reg 0x10: [mem 0xf801fffc-0xf803fffb 64bit]
> 
> Expected:
> pci 10000:80:02.0: reg 0x10: [mem 0xf8020000-0xf803ffff 64bit]
> 
> If other devices are mapped in the over-provisioned front, it could lead
> to resource conflict issues with VMD or those devices.
> 
> Fixes: a1a30170138c9 ("PCI: vmd: Fix shadow offsets to reflect spec changes")
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> ---
>  drivers/pci/controller/vmd.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Hi Jon,

it looks like I can take this patch for v5.8 whereas patch 2 depends
on the QEMU changes acceptance and should probably wait.

Please let me know your thoughts asap and I will try to at least
squeeze this patch in.

Lorenzo

> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index dac91d6..e386d4e 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -445,9 +445,11 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
>  			if (!membar2)
>  				return -ENOMEM;
>  			offset[0] = vmd->dev->resource[VMD_MEMBAR1].start -
> -					readq(membar2 + MB2_SHADOW_OFFSET);
> +					(readq(membar2 + MB2_SHADOW_OFFSET) &
> +					 PCI_BASE_ADDRESS_MEM_MASK);
>  			offset[1] = vmd->dev->resource[VMD_MEMBAR2].start -
> -					readq(membar2 + MB2_SHADOW_OFFSET + 8);
> +					(readq(membar2 + MB2_SHADOW_OFFSET + 8) &
> +					 PCI_BASE_ADDRESS_MEM_MASK);
>  			pci_iounmap(vmd->dev, membar2);
>  		}
>  	}
> -- 
> 1.8.3.1
>