KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

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 <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-ivpu b/Documentation/ABI/testing/sysfs-driver-ivpu
new file mode 100644
index 000000000..91685774e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-ivpu
@@ -0,0 +1,65 @@
+What:		/sys/bus/pci/drivers/intel_vpu/.../npu_busy_time_us
+Date:		May 2024
+KernelVersion:	6.11
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Time in microseconds that the device spent executing jobs. The time is
+		counted when and only when there are jobs submitted to firmware. This time
+		can be used to measure the utilization of NPU, either by calculating the
+		difference between two timepoints or monitoring utilization percentage by
+		reading periodically. Recommended read period is 1 second to avoid impact
+		on job submission performance. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../npu_memory_utilization
+Date:		Jan 2025
+KernelVersion:	6.15
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Current NPU memory utilization in bytes. Reports the total size of all
+		resident buffer objects allocated for NPU use. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_min_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Minimum frequency in MHz supported by the NPU hardware. This is a
+		hardware capability and cannot be changed. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_efficient_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Most efficient operating frequency in MHz for the NPU. This represents
+		the frequency at which the NPU operates most efficiently in terms of power
+		and performance. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_max_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Maximum frequency in MHz supported by the NPU hardware. This is a
+		hardware capability and cannot be changed. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/current_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Current operating frequency in MHz of the NPU. The value is valid only
+		when the device is active; returns 0 when idle. The actual frequency may
+		be lower than the requested range due to power or thermal constraints.
+		Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/set_min_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Configured minimum operating frequency in MHz (50XX devices and newer).
+		Values written are clamped to hardware limits (hw_min_freq to hw_max_freq).
+		If set_min_freq exceeds set_max_freq, the driver clamps set_min_freq to
+		set_max_freq when selecting the operating frequency. Read-write.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/set_max_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Configured maximum operating frequency in MHz (50XX devices and newer).
+		Values written are clamped to hardware limits (hw_min_freq to hw_max_freq).
+		Read-write.