On Mon, Apr 30, 2018 at 04:37:48PM +0200, Christoffer Dall wrote:
On Sun, Apr 29, 2018 at 02:34:45PM +0200, gregkh@linuxfoundation.org wrote:
The patch below was submitted to be applied to the 4.16-stable tree.
I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.
I could be totally wrong, and if so, please respond to stable@vger.kernel.org and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.
This patch ensures that current userspace drivers of KVM VMs will fail migration to targets that do not support spectre/meltdown mitigations. Without this patch, VMs can be migrated to hosts that do not have mitigation support without any warning to the system admin. We considered this a real security issue as per the stable kernel rules.
If you disagree, feel free to drop this patch without further discussion.
Thanks, -Christoffer
------------------ original commit in Linus's tree ------------------
From 85bd0ba1ff9875798fad94218b627ea9f768f3c3 Mon Sep 17 00:00:00 2001 From: Marc Zyngier marc.zyngier@arm.com Date: Sun, 21 Jan 2018 16:42:56 +0000 Subject: [PATCH] arm/arm64: KVM: Add PSCI version selection API
Although we've implemented PSCI 0.1, 0.2 and 1.0, we expose either 0.1 or 1.0 to a guest, defaulting to the latest version of the PSCI implementation that is compatible with the requested version. This is no different from doing a firmware upgrade on KVM.
But in order to give a chance to hypothetical badly implemented guests that would have a fit by discovering something other than PSCI 0.2, let's provide a new API that allows userspace to pick one particular version of the API.
This is implemented as a new class of "firmware" registers, where we expose the PSCI version. This allows the PSCI version to be save/restored as part of a guest migration, and also set to any supported version if the guest requires it.
Cc: stable@vger.kernel.org #4.16 Reviewed-by: Christoffer Dall cdall@kernel.org Signed-off-by: Marc Zyngier marc.zyngier@arm.com
Also, it looks like this applies cleanly to 4.14.y, do you want it there as well?
thanks,
greg k-h