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/sysfs-class-powercap | 152 +++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-powercap (limited to 'Documentation/ABI/testing/sysfs-class-powercap') diff --git a/Documentation/ABI/testing/sysfs-class-powercap b/Documentation/ABI/testing/sysfs-class-powercap new file mode 100644 index 000000000..ca491ec4e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-powercap @@ -0,0 +1,152 @@ +What: /sys/class/powercap/ +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + The powercap/ class sub directory belongs to the power cap + subsystem. Refer to + Documentation/power/powercap/powercap.rst for details. + +What: /sys/class/powercap/ +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + A is a unique name under /sys/class/powercap. + Here determines how the power is going to be + controlled. A can contain multiple power zones. + +What: /sys/class/powercap//enabled +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + This allows to enable/disable power capping for a "control type". + This status affects every power zone using this "control_type. + +What: /sys/class/powercap// +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + A power zone is a single or a collection of devices, which can + be independently monitored and controlled. A power zone sysfs + entry is qualified with the name of the . + E.g. intel-rapl:0:1:1. + +What: /sys/class/powercap/// +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Power zones may be organized in a hierarchy in which child + power zones provide monitoring and control for a subset of + devices under the parent. For example, if there is a parent + power zone for a whole CPU package, each CPU core in it can + be a child power zone. + +What: /sys/class/powercap/...//name +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Specifies the name of this power zone. + +What: /sys/class/powercap/...//energy_uj +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Current energy counter in micro-joules. Write "0" to reset. + If the counter can not be reset, then this attribute is + read-only. + +What: /sys/class/powercap/...//max_energy_range_uj +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Range of the above energy counter in micro-joules. + + +What: /sys/class/powercap/...//power_uw +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Current power in micro-watts. + +What: /sys/class/powercap/...//max_power_range_uw +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Range of the above power value in micro-watts. + +What: /sys/class/powercap/...//constraint_X_name +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Each power zone can define one or more constraints. Each + constraint can have an optional name. Here "X" can have values + from 0 to max integer. + +What: /sys/class/powercap/...//constraint_X_power_limit_uw +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Power limit in micro-watts should be applicable for + the time window specified by "constraint_X_time_window_us". + Here "X" can have values from 0 to max integer. + +What: /sys/class/powercap/...//constraint_X_time_window_us +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Time window in micro seconds. This is used along with + constraint_X_power_limit_uw to define a power constraint. + Here "X" can have values from 0 to max integer. + + +What: /sys/class/powercap//.../constraint_X_max_power_uw +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Maximum allowed power in micro watts for this constraint. + Here "X" can have values from 0 to max integer. + +What: /sys/class/powercap//.../constraint_X_min_power_uw +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Minimum allowed power in micro watts for this constraint. + Here "X" can have values from 0 to max integer. + +What: /sys/class/powercap/...//constraint_X_max_time_window_us +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Maximum allowed time window in micro seconds for this + constraint. Here "X" can have values from 0 to max integer. + +What: /sys/class/powercap/...//constraint_X_min_time_window_us +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + Minimum allowed time window in micro seconds for this + constraint. Here "X" can have values from 0 to max integer. + +What: /sys/class/powercap/...//enabled +Date: September 2013 +KernelVersion: 3.13 +Contact: linux-pm@vger.kernel.org +Description: + This allows to enable/disable power capping at power zone level. + This applies to current power zone and its children. -- cgit v1.3.1