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authorSean Christopherson <seanjc@google.com>2026-09-23 09:37:21 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2026-09-26 00:39:55 -0400
commit93de2a6a4b91b72607136dd656edf03fb399d27f (patch)
tree9220c76eb23cb39a146fac9692ee69afa4aa3135 /Documentation/ABI/testing/sysfs-class-bsr
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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>
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+What: /sys/class/bsr/bsr*/bsr_size
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) Size of the barrier-synchronization register (BSR)
+ register in bytes.
+
+What: /sys/class/bsr/bsr*/bsr_length
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) The length of memory region that can be mapped in bytes.
+
+What: /sys/class/bsr/bsr*/bsr_stride
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) The stride or the interval at which the allocated BSR bytes
+ repeat within the mapping.