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-rnbd-server | 58 +++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rnbd-server (limited to 'Documentation/ABI/testing/sysfs-class-rnbd-server') diff --git a/Documentation/ABI/testing/sysfs-class-rnbd-server b/Documentation/ABI/testing/sysfs-class-rnbd-server new file mode 100644 index 000000000..6c5996cd7 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rnbd-server @@ -0,0 +1,58 @@ +What: /sys/class/rnbd-server +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: provide information about RNBD-server. + +What: /sys/class/rnbd-server/ctl/ +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: When a client maps a device, a directory entry with the name of the + block device is created under /sys/class/rnbd-server/ctl/devices/. + +What: /sys/class/rnbd-server/ctl/devices//block_dev +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Is a symlink to the sysfs entry of the exported device. + + Example: + block_dev -> ../../../../class/block/ram0 + +What: /sys/class/rnbd-server/ctl/devices//sessions/ +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: For each client a particular device is exported to, following directory will be + created: + + /sys/class/rnbd-server/ctl/devices//sessions// + + When the device is unmapped by that client, the directory will be removed. + +What: /sys/class/rnbd-server/ctl/devices//sessions//read_only +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Contains '1' if device is mapped read-only, otherwise '0'. + +What: /sys/class/rnbd-server/ctl/devices//sessions//mapping_path +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Contains the relative device path provided by the user during mapping. + +What: /sys/class/rnbd-server/ctl/devices//sessions//access_mode +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Contains the device access mode: ro, rw or migration. + +What: /sys/class/rnbd-server/ctl/devices//sessions//force_close +Date: Nov 2020 +KernelVersion: 5.10 +Contact: Jack Wang Danil Kipnis +Description: Write "1" to the file to close the device on server side. Please + note that the client side device will not be closed, read or + write to the device will get -ENOTCONN. -- cgit v1.3.1