Subject: [PATCH] ARM: Use 64-bit DMA addresses for LPAE+VirtIO-MMIO

From: [email-masked] (Christopher Covington)
Date: Fri, 21 Mar 2014 15:44:57 -0400

Hi Catalin,

On 03/21/2014 12:27 PM, Catalin Marinas wrote:
> On Wed, Mar 19, 2014 at 05:35:19PM +0000, Christopher Covington wrote:
>> On an LPAE system, the physical addresses used by VirtIO-MMIO may
>> be larger than 32 bits, even if the header and configuration space
>> addresses fit into 32 bits. For example with the Versatile Express
>> memory map using 4G memory, the following error occured when trying
>> to use a VirtIO-MMIO block device.
>>
>> EXT2-fs (vda): error: ext2_check_page: bad entry in directory #2: :
>> unaligned directory entry - offset=0, inode=3755990991, rec_len=57311,
>> name_len=223
>>
>> To fix this, select ARCH_DMA_ADDR_T_64BIT when both LPAE and
>> VIRTIO_MMIO are selected.
>>
>> Signed-off-by: Christopher Covington <[email-masked]>
>> ---
>>  arch/arm/mm/Kconfig | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
>> index 1f8fed9..a62bcc9 100644
>> --- a/arch/arm/mm/Kconfig
>> +++ b/arch/arm/mm/Kconfig
>> @@ -617,6 +617,7 @@ config ARM_LPAE
>>  	bool "Support for the Large Physical Address Extension"
>>  	depends on MMU && CPU_32v7 && !CPU_32v6 && !CPU_32v5 && \
>>  		!CPU_32v4 && !CPU_32v3
>> +	select ARCH_DMA_ADDR_T_64BIT if VIRTIO_MMIO
> 
> That's the wrong place to enable ARCH_DMA_ADDR_T_64BIT. Do you have a
> platform with >32-bit physical address space? If yes, it should be
> selected there.

The platforms I'm currently using are models like the Versatile Express
RTSM/FVP. I can respin with changes to ARCH_VEXPRESS and ARCH_VIRT instead.

Thanks,
Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.