[PATCH v2 2/2] xen/mmu: enable SMMU subsystem only in MMU

Ayan Kumar Halder posted 2 patches 4 weeks, 1 day ago
There is a newer version of this series
[PATCH v2 2/2] xen/mmu: enable SMMU subsystem only in MMU
Posted by Ayan Kumar Halder 4 weeks, 1 day ago
From: Penny Zheng <Penny.Zheng@arm.com>

In Xen, SMMU subsystem is supported for MMU system only. The reason being SMMU
driver uses the same page tables as MMU.
Thus, we make it dependent on CONFIG_MMU.

Signed-off-by: Penny Zheng <Penny.Zheng@arm.com>
Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
---
Changes from 

v1 - 1. HAS_PASSTHROUGH is now enclosed within "config MMU".
There was a pending response on
"[PATCH v1 2/2] xen/mmu: enable SMMU subsystem only in MMU"
that it might introduce a bunch of #if-defs in arm specific common code.
However, there are alternative implementations possible to reduce
#if-defs. So, that can be decided at a later point in time and should
not block the current patch.

 xen/arch/arm/Kconfig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 15b2e4a227..adebf8d5ca 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -14,9 +14,7 @@ config ARM
 	select FUNCTION_ALIGNMENT_4B
 	select HAS_ALTERNATIVE if HAS_VMAP
 	select HAS_DEVICE_TREE
-	select HAS_PASSTHROUGH
 	select HAS_UBSAN
-	select IOMMU_FORCE_PT_SHARE
 
 config ARCH_DEFCONFIG
 	string
@@ -78,6 +76,8 @@ config MMU
 	bool "MMU"
 	select HAS_PMAP
 	select HAS_VMAP
+	select HAS_PASSTHROUGH
+	select IOMMU_FORCE_PT_SHARE
 	help
 	  Select it if you plan to run Xen on A-profile Armv7+
 
-- 
2.25.1
Re: [PATCH v2 2/2] xen/mmu: enable SMMU subsystem only in MMU
Posted by Julien Grall 3 weeks, 3 days ago
Hi Ayan,

On 27/11/2024 18:39, Ayan Kumar Halder wrote:
> From: Penny Zheng <Penny.Zheng@arm.com>
> 
> In Xen, SMMU subsystem is supported for MMU system only. The reason being SMMU
> driver uses the same page tables as MMU.
> Thus, we make it dependent on CONFIG_MMU.
> 
> Signed-off-by: Penny Zheng <Penny.Zheng@arm.com>
> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall