[PATCH] x86: always select SWIOTLB on x86_64

[PATCH] x86: always select SWIOTLB on x86_64

[Joerg Roedel]

Impact: fixes korg bugzilla 11980

A kernel for a 64bit x86 system should always contain the swiotlb code
in case it is booted on a machine without any hardware IOMMU supported
by the kernel and more than 4GB of RAM. This patch changes Kconfig to
always compile swiotlb into the kernel for x86_64.

Cc: hawk@pld-linux.org
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 93224b5..669c6d5 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -566,7 +566,7 @@ config AMD_IOMMU
 
 # need this always selected by IOMMU for the VIA workaround
 config SWIOTLB
-	bool
+	def_bool y if X86_64
 	help
 	  Support for software bounce buffers used on x86-64 systems
 	  which don't have a hardware IOMMU (e.g. the current generation
-- 
1.5.6.4

Re: [PATCH] x86: always select SWIOTLB on x86_64

[Ingo Molnar]

* Joerg Roedel <joerg.roedel@amd.com> wrote:

> Impact: fixes korg bugzilla 11980
> 
> A kernel for a 64bit x86 system should always contain the swiotlb code
> in case it is booted on a machine without any hardware IOMMU supported
> by the kernel and more than 4GB of RAM. This patch changes Kconfig to
> always compile swiotlb into the kernel for x86_64.
> 
> Cc: hawk@pld-linux.org
> Cc: stable@kernel.org
> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> ---
>  arch/x86/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

applied to tip/x86/iommu, thanks Joerg!

	Ingo

Re: [PATCH] x86: always select SWIOTLB on x86_64

[FUJITA Tomonori]

On Tue, 18 Nov 2008 12:44:21 +0100
Joerg Roedel <joerg.roedel@amd.com> wrote:

> Impact: fixes korg bugzilla 11980
> 
> A kernel for a 64bit x86 system should always contain the swiotlb code
> in case it is booted on a machine without any hardware IOMMU supported
> by the kernel and more than 4GB of RAM. This patch changes Kconfig to
> always compile swiotlb into the kernel for x86_64.

Yeah, as I wrote in a different thread, I think that it makes sense to
enable SWIOTLB at all times:

http://marc.info/?l=linux-kernel&m=122593287501949&w=2

An option asking an user if he has more than 4GB RAM or not, doesn't
make sense much.

BTW, you can also remove the help description, right?
 
> ---
>  arch/x86/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 93224b5..669c6d5 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -566,7 +566,7 @@ config AMD_IOMMU
>  
>  # need this always selected by IOMMU for the VIA workaround
>  config SWIOTLB
> -	bool
> +	def_bool y if X86_64
>  	help
>  	  Support for software bounce buffers used on x86-64 systems
>  	  which don't have a hardware IOMMU (e.g. the current generation
> -- 
> 1.5.6.4
> 
> 
> --
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