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-wilco-ec | 45 ++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-wilco-ec (limited to 'Documentation/ABI/testing/debugfs-wilco-ec') diff --git a/Documentation/ABI/testing/debugfs-wilco-ec b/Documentation/ABI/testing/debugfs-wilco-ec new file mode 100644 index 000000000..682e3c09e --- /dev/null +++ b/Documentation/ABI/testing/debugfs-wilco-ec @@ -0,0 +1,45 @@ +What: /sys/kernel/debug/wilco_ec/h1_gpio +Date: April 2019 +KernelVersion: 5.2 +Description: + As part of Chrome OS's FAFT (Fully Automated Firmware Testing) + tests, we need to ensure that the H1 chip is properly setting + some GPIO lines. The h1_gpio attribute exposes the state + of the lines: + - ENTRY_TO_FACT_MODE in BIT(0) + - SPI_CHROME_SEL in BIT(1) + + Output will formatted with "0x%02x\n". + +What: /sys/kernel/debug/wilco_ec/raw +Date: January 2019 +KernelVersion: 5.1 +Description: + Write and read raw mailbox commands to the EC. + + You can write a hexadecimal sentence to raw, and that series of + bytes will be sent to the EC. Then, you can read the bytes of + response by reading from raw. + + For writing, bytes 0-1 indicate the message type, one of enum + wilco_ec_msg_type. Byte 2+ consist of the data passed in the + request, starting at MBOX[0]. At least three bytes are required + for writing, two for the type and at least a single byte of + data. + + Example:: + + // Request EC info type 3 (EC firmware build date) + // Corresponds with sending type 0x00f0 with + // MBOX = [38, 00, 03, 00] + $ echo 00 f0 38 00 03 00 > /sys/kernel/debug/wilco_ec/raw + // View the result. The decoded ASCII result "12/21/18" is + // included after the raw hex. + // Corresponds with MBOX = [00, 00, 31, 32, 2f, 32, 31, 38, ...] + $ cat /sys/kernel/debug/wilco_ec/raw + 00 00 31 32 2f 32 31 2f 31 38 00 38 00 01 00 2f 00 ..12/21/18.8... + + Note that the first 16 bytes of the received MBOX[] will be + printed, even if some of the data is junk, and skipping bytes + 17 to 32. It is up to you to know how many of the first bytes of + data are the actual response. -- cgit v1.3.1