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-scmi | 70 ++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-scmi (limited to 'Documentation/ABI/testing/debugfs-scmi') diff --git a/Documentation/ABI/testing/debugfs-scmi b/Documentation/ABI/testing/debugfs-scmi new file mode 100644 index 000000000..ee7179ab2 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-scmi @@ -0,0 +1,70 @@ +What: /sys/kernel/debug/scmi//instance_name +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: The name of the underlying SCMI instance described by + all the debugfs accessors rooted at /sys/kernel/debug/scmi/, + expressed as the full name of the top DT SCMI node under which + this SCMI instance is rooted. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//atomic_threshold_us +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: An optional time value, expressed in microseconds, representing, + on this SCMI instance , the threshold above which any SCMI + command, advertised to have an higher-than-threshold execution + latency, should not be considered for atomic mode of operation, + even if requested. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/type +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: A string representing the type of transport configured for this + SCMI instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/is_atomic +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: A boolean stating if the transport configured on the underlying + SCMI instance is capable of atomic mode of operation. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/max_rx_timeout_ms +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Timeout in milliseconds allowed for SCMI synchronous replies + for the currently configured SCMI transport for instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/max_msg_size +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max message size of allowed SCMI messages for the currently + configured SCMI transport for instance . +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/tx_max_msg +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max number of concurrently allowed in-flight SCMI messages for + the currently configured SCMI transport for instance on the + TX channels. +Users: Debugging, any userspace test suite + +What: /sys/kernel/debug/scmi//transport/rx_max_msg +Date: March 2023 +KernelVersion: 6.3 +Contact: cristian.marussi@arm.com +Description: Max number of concurrently allowed in-flight SCMI messages for + the currently configured SCMI transport for instance on the + RX channels. +Users: Debugging, any userspace test suite -- cgit v1.3.1