Re: [PATCH v2 1/8] drivers/virt: Drop VIRT_DRIVERS build dependency

[Nathan Chancellor <nathan@kernel.org>]

Hi Dan,

On Wed, Nov 12, 2025 at 06:14:39PM -0800, Dan Williams wrote:
> All of the objects in drivers/virt/ have their own configuration symbols to
> gate compilation. I.e. nothing gets added to the kernel with
> CONFIG_VIRT_DRIVERS=y in isolation.
> 
> Unconditionally descend into drivers/virt/ so that consumers do not need to
> add an additional CONFIG_VIRT_DRIVERS dependency.
> 
> Fix warnings of the form:
> 
>     Kconfig warnings: (for reference only)
>        WARNING: unmet direct dependencies detected for TSM
>        Depends on [n]: VIRT_DRIVERS [=n]
>        Selected by [y]:
>        - PCI_TSM [=y] && PCI [=y]

I can still trigger this warning on next-20251202, which contains this
change as commit 110c155e8a68 ("drivers/virt: Drop VIRT_DRIVERS build
dependency").

  $ git merge-base --is-ancestor 110c155e8a684d8b2423a72cfde147903881f765 HEAD
    echo $status
  0

  $ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux- clean defconfig

  $ scripts/config -e PCI_TSM

  $ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux- olddefconfig
  WARNING: unmet direct dependencies detected for TSM
    Depends on [n]: VIRT_DRIVERS [=n]
    Selected by [y]:
    - PCI_TSM [=y] && PCI [=y]

I would think you would need something like this avoid the problem but I
am not sure if it would be acceptable, hence just the report.

Cheers,
Nathan

diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index d8c848cf09a6..52eb7e4ba71f 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -47,6 +47,6 @@ source "drivers/virt/nitro_enclaves/Kconfig"
 
 source "drivers/virt/acrn/Kconfig"
 
-source "drivers/virt/coco/Kconfig"
-
 endif
+
+source "drivers/virt/coco/Kconfig"
diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig
index bb0c6d6ddcc8..df1cfaf26c65 100644
--- a/drivers/virt/coco/Kconfig
+++ b/drivers/virt/coco/Kconfig
@@ -3,6 +3,7 @@
 # Confidential computing related collateral
 #
 
+if VIRT_DRIVERS
 source "drivers/virt/coco/efi_secret/Kconfig"
 
 source "drivers/virt/coco/pkvm-guest/Kconfig"
@@ -14,6 +15,7 @@ source "drivers/virt/coco/tdx-guest/Kconfig"
 source "drivers/virt/coco/arm-cca-guest/Kconfig"
 
 source "drivers/virt/coco/guest/Kconfig"
+endif
 
 config TSM
 	bool