2008-11-18 11:44:41

by Joerg Roedel

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

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: [email protected]
Cc: [email protected]
Signed-off-by: Joerg Roedel <[email protected]>
---
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

2008-11-18 13:52:12

by Ingo Molnar

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

* Joerg Roedel <[email protected]> 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: [email protected]
> Cc: [email protected]
> Signed-off-by: Joerg Roedel <[email protected]>
> ---
> arch/x86/Kconfig | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)

applied to tip/x86/iommu, thanks Joerg!

Ingo

2008-11-19 05:44:18

by FUJITA Tomonori

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

On Tue, 18 Nov 2008 12:44:21 +0100
Joerg Roedel <[email protected]> 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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