[PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled

[PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled

[Alexandru Elisei]

Recent changes to KVM for arm64 has made it impossible for the host to
hibernate or use kexec when protected mode is enabled via the kernel
command line.

There are people who rely on kexec (for example, developers who use kexec
as a quick way to test a new kernel), let's document this change in
behaviour, so it doesn't catch them by surprise and we have a place to
point people to if it does.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
Based on the tip of the pkvm/restrict-hypercalls series [1]

[1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/pkvm/restrict-hypercalls

 Documentation/admin-guide/kernel-parameters.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 91ba391f9b32..741e33fd444a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2372,7 +2372,9 @@
 				   state is kept private from the host.
 				   Not valid if the kernel is running in EL2.
 
-			Defaults to VHE/nVHE based on hardware support.
+			Defaults to VHE/nVHE based on hardware support. Setting
+			mode to "protected" will disable kexec and hibernation
+			for the host.
 
 	kvm-arm.vgic_v3_group0_trap=
 			[KVM,ARM] Trap guest accesses to GICv3 group-0
-- 
2.33.0


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Re: [PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled

[Marc Zyngier]

On Mon, 11 Oct 2021 16:38:35 +0100, Alexandru Elisei wrote:
> Recent changes to KVM for arm64 has made it impossible for the host to
> hibernate or use kexec when protected mode is enabled via the kernel
> command line.
> 
> There are people who rely on kexec (for example, developers who use kexec
> as a quick way to test a new kernel), let's document this change in
> behaviour, so it doesn't catch them by surprise and we have a place to
> point people to if it does.

Applied to next, thanks!

[1/1] Documentation: admin-guide: Document side effects when pKVM is enabled
      commit: 53e8ce137f7b34bd7a54429d18e0d0e5f56f54e8

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.



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