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-thermal | 259 ++++++++++++++++++++++++++ 1 file changed, 259 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-thermal (limited to 'Documentation/ABI/testing/sysfs-class-thermal') diff --git a/Documentation/ABI/testing/sysfs-class-thermal b/Documentation/ABI/testing/sysfs-class-thermal new file mode 100644 index 000000000..968d89e15 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-thermal @@ -0,0 +1,259 @@ +What: /sys/class/thermal/thermal_zoneX/type +Description: + Strings which represent the thermal zone type. + This is given by thermal zone driver as part of registration. + E.g: "acpitz" indicates it's an ACPI thermal device. + In order to keep it consistent with hwmon sys attribute; this + should be a short, lowercase string, not containing spaces nor + dashes. + + RO, Required + +What: /sys/class/thermal/thermal_zoneX/temp +Description: + Current temperature as reported by thermal zone (sensor). + + Unit: millidegree Celsius + + RO, Required + +What: /sys/class/thermal/thermal_zoneX/mode +Description: + One of the predefined values in [enabled, disabled]. + This file gives information about the algorithm that is + currently managing the thermal zone. It can be either default + kernel based algorithm or user space application. + + enabled + enable Kernel Thermal management. + disabled + Preventing kernel thermal zone driver actions upon + trip points so that user application can take full + charge of the thermal management. + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/policy +Description: + One of the various thermal governors used for a particular zone. + + RW, Required + +What: /sys/class/thermal/thermal_zoneX/available_policies +Description: + Available thermal governors which can be used for a + particular zone. + + RO, Required + +What: /sys/class/thermal/thermal_zoneX/trip_point_Y_temp +Description: + The temperature above which trip point will be fired. + + Unit: millidegree Celsius + + RO, Optional + +What: /sys/class/thermal/thermal_zoneX/trip_point_Y_type +Description: + Strings which indicate the type of the trip point. + + E.g. it can be one of critical, hot, passive, `active[0-*]` + for ACPI thermal zone. + + RO, Optional + +What: /sys/class/thermal/thermal_zoneX/trip_point_Y_hyst +Description: + The hysteresis value for a trip point, represented as an + integer. + + Unit: Celsius + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/cdevY +Description: + Sysfs link to the thermal cooling device node where the sys I/F + for cooling device throttling control represents. + + RO, Optional + +What: /sys/class/thermal/thermal_zoneX/cdevY_trip_point +Description: + The trip point in this thermal zone which `cdev[0-*]` is + associated with; -1 means the cooling device is not + associated with any trip point. + + RO, Optional + +What: /sys/class/thermal/thermal_zoneX/cdevY_weight +Description: + The influence of `cdev[0-*]` in this thermal zone. This value + is relative to the rest of cooling devices in the thermal + zone. For example, if a cooling device has a weight double + than that of other, it's twice as effective in cooling the + thermal zone. + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/emul_temp +Description: + Interface to set the emulated temperature method in thermal zone + (sensor). After setting this temperature, the thermal zone may + pass this temperature to platform emulation function if + registered or cache it locally. This is useful in debugging + different temperature threshold and its associated cooling + action. This is write only node and writing 0 on this node + should disable emulation. + + Unit: millidegree Celsius + + WO, Optional + + WARNING: + Be careful while enabling this option on production systems, + because userland can easily disable the thermal policy by simply + flooding this sysfs node with low temperature values. + + +What: /sys/class/thermal/thermal_zoneX/k_d +Description: + The derivative term of the power allocator governor's PID + controller. For more information see + Documentation/driver-api/thermal/power_allocator.rst + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/k_i +Description: + The integral term of the power allocator governor's PID + controller. This term allows the PID controller to compensate + for long term drift. For more information see + Documentation/driver-api/thermal/power_allocator.rst + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/k_po +Description: + The proportional term of the power allocator governor's PID + controller during temperature overshoot. Temperature overshoot + is when the current temperature is above the "desired + temperature" trip point. For more information see + Documentation/driver-api/thermal/power_allocator.rst + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/k_pu +Description: + The proportional term of the power allocator governor's PID + controller during temperature undershoot. Temperature undershoot + is when the current temperature is below the "desired + temperature" trip point. For more information see + Documentation/driver-api/thermal/power_allocator.rst + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/integral_cutoff +Description: + Temperature offset from the desired temperature trip point + above which the integral term of the power allocator + governor's PID controller starts accumulating errors. For + example, if integral_cutoff is 0, then the integral term only + accumulates error when temperature is above the desired + temperature trip point. For more information see + Documentation/driver-api/thermal/power_allocator.rst + + Unit: millidegree Celsius + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/slope +Description: + The slope constant used in a linear extrapolation model + to determine a hotspot temperature based off the sensor's + raw readings. It is up to the device driver to determine + the usage of these values. + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/offset +Description: + The offset constant used in a linear extrapolation model + to determine a hotspot temperature based off the sensor's + raw readings. It is up to the device driver to determine + the usage of these values. + + RW, Optional + +What: /sys/class/thermal/thermal_zoneX/sustainable_power +Description: + An estimate of the sustained power that can be dissipated by + the thermal zone. Used by the power allocator governor. For + more information see + Documentation/driver-api/thermal/power_allocator.rst + + Unit: milliwatts + + RW, Optional + +What: /sys/class/thermal/cooling_deviceX/type +Description: + String which represents the type of device, e.g: + + - for generic ACPI: should be "Fan", "Processor" or "LCD" + - for memory controller device on intel_menlow platform: + should be "Memory controller". + + RO, Required + +What: /sys/class/thermal/cooling_deviceX/max_state +Description: + The maximum permissible cooling state of this cooling device. + + RO, Required + +What: /sys/class/thermal/cooling_deviceX/cur_state +Description: + The current cooling state of this cooling device. + The value can any integer numbers between 0 and max_state: + + - cur_state == 0 means no cooling + - cur_state == max_state means the maximum cooling. + + RW, Required + +What: /sys/class/thermal/cooling_deviceX/stats/reset +Description: + Writing any value resets the cooling device's statistics. + + WO, Required + +What: /sys/class/thermal/cooling_deviceX/stats/time_in_state_ms: +Description: + The amount of time spent by the cooling device in various + cooling states. The output will have "