Re: [PATCH v7 10/11] virt: arm-cca-guest: TSM_REPORT support for realms

On Wed, Dec 04, 2024 at 01:16:05PM -0800, Dan Williams wrote:

Steven Price wrote:

quoted

diff --git a/drivers/virt/coco/arm-cca-guest/Kconfig b/drivers/virt/coco/arm-cca-guest/Kconfig
new file mode 100644
index 000000000000..9dd27c3ee215
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-guest/Kconfig

@@ -0,0 +1,11 @@
+config ARM_CCA_GUEST
+	tristate "Arm CCA Guest driver"
+	depends on ARM64
+	default m

I am working on some updates to the TSM_REPORTS interface, rebased them
to test the changes with this driver, and discovered that this driver is
enabled by default.

Just a reminder to please do not mark new drivers as "default m" [1]. In
this case it is difficult to imagine that every arm64 kernel on the
planet needs this functionality enabled by default. In general, someone
should be able to run olddefconfig with a new kernel and not be exposed
to brand new drivers that they have not considered previously.

[1]: http://lore.kernel.org/CA+55aFzxL6-Xp=-mnBwMisZsuKhRZ6zRDJoAmH8W5LDHU2oJuw@mail.gmail.com/ (local)

Fair point, the pKVM driver is also default off. At least with the arm64
defconfig, VIRT_DRIVERS is default off, so this wouldn't be built. But
an olddefconfig will indeed enable it (this reminds me to add the coco
drivers to my test configs).

-- 
Catalin