From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- Documentation/ABI/testing/debugfs-ec | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-ec (limited to 'Documentation/ABI/testing/debugfs-ec') diff --git a/Documentation/ABI/testing/debugfs-ec b/Documentation/ABI/testing/debugfs-ec new file mode 100644 index 000000000..ab6099daa --- /dev/null +++ b/Documentation/ABI/testing/debugfs-ec @@ -0,0 +1,21 @@ +What: /sys/kernel/debug/ec/*/{gpe,use_global_lock,io} +Date: July 2010 +Contact: Thomas Renninger +Description: + +General information like which GPE is assigned to the EC and whether +the global lock should get used. +Knowing the EC GPE one can watch the amount of HW events related to +the EC here (XY -> GPE number from `/sys/kernel/debug/ec/*/gpe`): +/sys/firmware/acpi/interrupts/gpeXY + +The io file is binary and a userspace tool located here: +ftp://ftp.suse.com/pub/people/trenn/sources/ec/ +should get used to read out the 256 Embedded Controller registers +or writing to them. + +CAUTION: + Do not write to the Embedded Controller if you don't know + what you are doing! Rebooting afterwards also is a good idea. + This can influence the way your machine is cooled and fans may + not get switched on again after you did a wrong write. -- cgit v1.3.1