linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Alexandru Elisei <alexandru.elisei@arm.com>
To: corbet@lwn.net, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
	will@kernel.org, maz@kernel.org, james.morse@arm.com,
	suzuki.poulose@arm.com, kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled
Date: Mon, 11 Oct 2021 16:38:35 +0100	[thread overview]
Message-ID: <20211011153835.291147-1-alexandru.elisei@arm.com> (raw)

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


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2021-10-11 15:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-11 15:38 Alexandru Elisei [this message]
2021-10-11 15:55 ` [PATCH] Documentation: admin-guide: Document side effects when pKVM is enabled Marc Zyngier

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20211011153835.291147-1-alexandru.elisei@arm.com \
    --to=alexandru.elisei@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=corbet@lwn.net \
    --cc=james.morse@arm.com \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=suzuki.poulose@arm.com \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).