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, 27 insertions, 0 deletions

diff --git a/Documentation/admin-guide/lcd-panel-cgram.rst b/Documentation/admin-guide/lcd-panel-cgram.rst
new file mode 100644
index 000000000..a3eb00c62
--- /dev/null
+++ b/Documentation/admin-guide/lcd-panel-cgram.rst
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+======================================
+Parallel port LCD/Keypad Panel support
+======================================
+
+Some LCDs allow you to define up to 8 characters, mapped to ASCII
+characters 0 to 7. The escape code to define a new character is
+'\e[LG' followed by one digit from 0 to 7, representing the character
+number, and up to 8 couples of hex digits terminated by a semi-colon
+(';'). Each couple of digits represents a line, with 1-bits for each
+illuminated pixel with LSB on the right. Lines are numbered from the
+top of the character to the bottom. On a 5x7 matrix, only the 5 lower
+bits of the 7 first bytes are used for each character. If the string
+is incomplete, only complete lines will be redefined. Here are some
+examples::
+
+  printf "\e[LG0010101050D1F0C04;"  => 0 = [enter]
+  printf "\e[LG1040E1F0000000000;"  => 1 = [up]
+  printf "\e[LG2000000001F0E0400;"  => 2 = [down]
+  printf "\e[LG3040E1F001F0E0400;"  => 3 = [up-down]
+  printf "\e[LG40002060E1E0E0602;"  => 4 = [left]
+  printf "\e[LG500080C0E0F0E0C08;"  => 5 = [right]
+  printf "\e[LG60016051516141400;"  => 6 = "IP"
+
+  printf "\e[LG00103071F1F070301;"  => big speaker
+  printf "\e[LG00002061E1E060200;"  => small speaker
+
+Willy