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>

1 files changed, 61 insertions, 0 deletions

diff --git a/Documentation/filesystems/hfsplus.rst b/Documentation/filesystems/hfsplus.rst
new file mode 100644
index 000000000..f02f4f5fc
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+++ b/Documentation/filesystems/hfsplus.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+======================================
+Macintosh HFSPlus Filesystem for Linux
+======================================
+
+HFSPlus is a filesystem first introduced in MacOS 8.1.
+HFSPlus has several extensions to HFS, including 32-bit allocation
+blocks, 255-character unicode filenames, and file sizes of 2^63 bytes.
+
+
+Mount options
+=============
+
+When mounting an HFSPlus filesystem, the following options are accepted:
+
+  creator=cccc, type=cccc
+	Specifies the creator/type values as shown by the MacOS finder
+	used for creating new files.  Default values: '????'.
+
+  uid=n, gid=n
+	Specifies the user/group that owns all files on the filesystem
+	that have uninitialized permissions structures.
+	Default:  user/group id of the mounting process.
+
+  umask=n
+	Specifies the umask (in octal) used for files and directories
+	that have uninitialized permissions structures.
+	Default:  umask of the mounting process.
+
+  session=n
+	Select the CDROM session to mount as HFSPlus filesystem.  Defaults to
+	leaving that decision to the CDROM driver.  This option will fail
+	with anything but a CDROM as underlying devices.
+
+  part=n
+	Select partition number n from the devices.  This option only makes
+	sense for CDROMs because they can't be partitioned under Linux.
+	For disk devices the generic partition parsing code does this
+	for us.  Defaults to not parsing the partition table at all.
+
+  decompose
+	Decompose file name characters.
+
+  nodecompose
+	Do not decompose file name characters.
+
+  force
+	Used to force write access to volumes that are marked as journalled
+	or locked.  Use at your own risk.
+
+  nls=cccc
+	Encoding to use when presenting file names.
+
+
+References
+==========
+
+kernel source:		<file:fs/hfsplus>
+
+Apple Technote 1150	https://developer.apple.com/legacy/library/technotes/tn/tn1150.html