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-vfio | 57 ++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-vfio (limited to 'Documentation/ABI/testing/debugfs-vfio') diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio new file mode 100644 index 000000000..ed2f29c3a --- /dev/null +++ b/Documentation/ABI/testing/debugfs-vfio @@ -0,0 +1,57 @@ +What: /sys/kernel/debug/vfio +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: This debugfs file directory is used for debugging + of vfio devices, it's a common directory for all vfio devices. + Vfio core will create a device subdirectory under this + directory. + +What: /sys/kernel/debug/vfio//migration +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: This debugfs file directory is used for debugging + of vfio devices that support live migration. + The debugfs of each vfio device that supports live migration + could be created under this directory. + +What: /sys/kernel/debug/vfio//migration/state +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: Read the live migration status of the vfio device. + The contents of the state file reflects the migration state + relative to those defined in the vfio_device_mig_state enum + +What: /sys/kernel/debug/vfio//migration/features +Date: Oct 2025 +KernelVersion: 6.18 +Contact: Cédric Le Goater +Description: Read the migration features of the vfio device. + +What: /sys/kernel/debug/vfio//pci +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: This debugfs file directory is used for debugging + VFIO PCI devices. + +What: /sys/kernel/debug/vfio//pci/nointxmask +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: Read the nointxmask policy latched for this device. This + policy governs whether the device may use PCI 2.3 style + INTx masking when supported, reporting a value of "N", or + requires APIC level INTx masking, reporting a value of "Y". + +What: /sys/kernel/debug/vfio//pci/disable_idle_d3 +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: Read the disable_idle_d3 policy latched for this device. This + policy governs whether the device PM runtime usage count is + kept elevated while the device is bound to the driver and + unused, reporting a value of "Y", or decremented to allow the + device to enter a low power state, reporting a value of "N". -- cgit v1.3.1