From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc@google.com>
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 <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>
---
 scripts/atomic/kerneldoc/add                 | 13 +++++++++++++
 scripts/atomic/kerneldoc/add_negative        | 13 +++++++++++++
 scripts/atomic/kerneldoc/add_unless          | 19 +++++++++++++++++++
 scripts/atomic/kerneldoc/and                 | 13 +++++++++++++
 scripts/atomic/kerneldoc/andnot              | 13 +++++++++++++
 scripts/atomic/kerneldoc/cmpxchg             | 15 +++++++++++++++
 scripts/atomic/kerneldoc/dec                 | 12 ++++++++++++
 scripts/atomic/kerneldoc/dec_and_test        | 12 ++++++++++++
 scripts/atomic/kerneldoc/dec_if_positive     | 13 +++++++++++++
 scripts/atomic/kerneldoc/dec_unless_positive | 13 +++++++++++++
 scripts/atomic/kerneldoc/inc                 | 12 ++++++++++++
 scripts/atomic/kerneldoc/inc_and_test        | 12 ++++++++++++
 scripts/atomic/kerneldoc/inc_not_zero        | 13 +++++++++++++
 scripts/atomic/kerneldoc/inc_unless_negative | 13 +++++++++++++
 scripts/atomic/kerneldoc/or                  | 13 +++++++++++++
 scripts/atomic/kerneldoc/read                | 12 ++++++++++++
 scripts/atomic/kerneldoc/set                 | 13 +++++++++++++
 scripts/atomic/kerneldoc/sub                 | 13 +++++++++++++
 scripts/atomic/kerneldoc/sub_and_test        | 13 +++++++++++++
 scripts/atomic/kerneldoc/try_cmpxchg         | 16 ++++++++++++++++
 scripts/atomic/kerneldoc/xchg                | 13 +++++++++++++
 scripts/atomic/kerneldoc/xor                 | 13 +++++++++++++
 22 files changed, 292 insertions(+)
 create mode 100644 scripts/atomic/kerneldoc/add
 create mode 100644 scripts/atomic/kerneldoc/add_negative
 create mode 100644 scripts/atomic/kerneldoc/add_unless
 create mode 100644 scripts/atomic/kerneldoc/and
 create mode 100644 scripts/atomic/kerneldoc/andnot
 create mode 100644 scripts/atomic/kerneldoc/cmpxchg
 create mode 100644 scripts/atomic/kerneldoc/dec
 create mode 100644 scripts/atomic/kerneldoc/dec_and_test
 create mode 100644 scripts/atomic/kerneldoc/dec_if_positive
 create mode 100644 scripts/atomic/kerneldoc/dec_unless_positive
 create mode 100644 scripts/atomic/kerneldoc/inc
 create mode 100644 scripts/atomic/kerneldoc/inc_and_test
 create mode 100644 scripts/atomic/kerneldoc/inc_not_zero
 create mode 100644 scripts/atomic/kerneldoc/inc_unless_negative
 create mode 100644 scripts/atomic/kerneldoc/or
 create mode 100644 scripts/atomic/kerneldoc/read
 create mode 100644 scripts/atomic/kerneldoc/set
 create mode 100644 scripts/atomic/kerneldoc/sub
 create mode 100644 scripts/atomic/kerneldoc/sub_and_test
 create mode 100644 scripts/atomic/kerneldoc/try_cmpxchg
 create mode 100644 scripts/atomic/kerneldoc/xchg
 create mode 100644 scripts/atomic/kerneldoc/xor

(limited to 'scripts/atomic/kerneldoc')

diff --git a/scripts/atomic/kerneldoc/add b/scripts/atomic/kerneldoc/add
new file mode 100644
index 000000000..991f3dafc
--- /dev/null
+++ b/scripts/atomic/kerneldoc/add
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic add with ${desc_order} ordering
+ * @i: ${int} value to add
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v + @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/add_negative b/scripts/atomic/kerneldoc/add_negative
new file mode 100644
index 000000000..f4ca1f05d
--- /dev/null
+++ b/scripts/atomic/kerneldoc/add_negative
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic add and test if negative with ${desc_order} ordering
+ * @i: ${int} value to add
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v + @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if the resulting value of @v is negative, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/add_unless b/scripts/atomic/kerneldoc/add_unless
new file mode 100644
index 000000000..fbc2fadfb
--- /dev/null
+++ b/scripts/atomic/kerneldoc/add_unless
@@ -0,0 +1,19 @@
+if [ -z "${pfx}" ]; then
+	desc_return="Return: @true if @v was updated, @false otherwise."
+fi
+
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic add unless value with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ * @a: ${int} value to add
+ * @u: ${int} value to compare with
+ *
+ * If (@v != @u), atomically updates @v to (@v + @a) with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/and b/scripts/atomic/kerneldoc/and
new file mode 100644
index 000000000..a92357435
--- /dev/null
+++ b/scripts/atomic/kerneldoc/and
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic bitwise AND with ${desc_order} ordering
+ * @i: ${int} value
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v & @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/andnot b/scripts/atomic/kerneldoc/andnot
new file mode 100644
index 000000000..64bb509f8
--- /dev/null
+++ b/scripts/atomic/kerneldoc/andnot
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic bitwise AND NOT with ${desc_order} ordering
+ * @i: ${int} value
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v & ~@i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/cmpxchg b/scripts/atomic/kerneldoc/cmpxchg
new file mode 100644
index 000000000..02b24ee9d
--- /dev/null
+++ b/scripts/atomic/kerneldoc/cmpxchg
@@ -0,0 +1,15 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic compare and exchange with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ * @old: ${int} value to compare with
+ * @new: ${int} value to assign
+ *
+ * If (@v == @old), atomically updates @v to @new with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: The original value of @v.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/dec b/scripts/atomic/kerneldoc/dec
new file mode 100644
index 000000000..bbeecbc4c
--- /dev/null
+++ b/scripts/atomic/kerneldoc/dec
@@ -0,0 +1,12 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic decrement with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v - 1) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/dec_and_test b/scripts/atomic/kerneldoc/dec_and_test
new file mode 100644
index 000000000..71bbd23ce
--- /dev/null
+++ b/scripts/atomic/kerneldoc/dec_and_test
@@ -0,0 +1,12 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic decrement and test if zero with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v - 1) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if the resulting value of @v is zero, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/dec_if_positive b/scripts/atomic/kerneldoc/dec_if_positive
new file mode 100644
index 000000000..9468b4a69
--- /dev/null
+++ b/scripts/atomic/kerneldoc/dec_if_positive
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic decrement if positive with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * If (@v > 0), atomically updates @v to (@v - 1) with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: The old value of (@v - 1), regardless of whether @v was updated.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/dec_unless_positive b/scripts/atomic/kerneldoc/dec_unless_positive
new file mode 100644
index 000000000..06a678678
--- /dev/null
+++ b/scripts/atomic/kerneldoc/dec_unless_positive
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic decrement unless positive with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * If (@v <= 0), atomically updates @v to (@v - 1) with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if @v was updated, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/inc b/scripts/atomic/kerneldoc/inc
new file mode 100644
index 000000000..9f14f1b3d
--- /dev/null
+++ b/scripts/atomic/kerneldoc/inc
@@ -0,0 +1,12 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic increment with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v + 1) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/inc_and_test b/scripts/atomic/kerneldoc/inc_and_test
new file mode 100644
index 000000000..971694d59
--- /dev/null
+++ b/scripts/atomic/kerneldoc/inc_and_test
@@ -0,0 +1,12 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic increment and test if zero with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v + 1) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if the resulting value of @v is zero, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/inc_not_zero b/scripts/atomic/kerneldoc/inc_not_zero
new file mode 100644
index 000000000..c1a30fc66
--- /dev/null
+++ b/scripts/atomic/kerneldoc/inc_not_zero
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic increment unless zero with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * If (@v != 0), atomically updates @v to (@v + 1) with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if @v was updated, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/inc_unless_negative b/scripts/atomic/kerneldoc/inc_unless_negative
new file mode 100644
index 000000000..ece0d2c7b
--- /dev/null
+++ b/scripts/atomic/kerneldoc/inc_unless_negative
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic increment unless negative with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * If (@v >= 0), atomically updates @v to (@v + 1) with ${desc_order} ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if @v was updated, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/or b/scripts/atomic/kerneldoc/or
new file mode 100644
index 000000000..55b33de50
--- /dev/null
+++ b/scripts/atomic/kerneldoc/or
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic bitwise OR with ${desc_order} ordering
+ * @i: ${int} value
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v | @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/read b/scripts/atomic/kerneldoc/read
new file mode 100644
index 000000000..89fe6147c
--- /dev/null
+++ b/scripts/atomic/kerneldoc/read
@@ -0,0 +1,12 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic load with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically loads the value of @v with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: The value loaded from @v.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/set b/scripts/atomic/kerneldoc/set
new file mode 100644
index 000000000..e82cb9ebb
--- /dev/null
+++ b/scripts/atomic/kerneldoc/set
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic set with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ * @i: ${int} value to assign
+ *
+ * Atomically sets @v to @i with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: Nothing.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/sub b/scripts/atomic/kerneldoc/sub
new file mode 100644
index 000000000..3ba642d04
--- /dev/null
+++ b/scripts/atomic/kerneldoc/sub
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic subtract with ${desc_order} ordering
+ * @i: ${int} value to subtract
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v - @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/sub_and_test b/scripts/atomic/kerneldoc/sub_and_test
new file mode 100644
index 000000000..96615e508
--- /dev/null
+++ b/scripts/atomic/kerneldoc/sub_and_test
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic subtract and test if zero with ${desc_order} ordering
+ * @i: ${int} value to subtract
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v - @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if the resulting value of @v is zero, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/try_cmpxchg b/scripts/atomic/kerneldoc/try_cmpxchg
new file mode 100644
index 000000000..4dfc7a167
--- /dev/null
+++ b/scripts/atomic/kerneldoc/try_cmpxchg
@@ -0,0 +1,16 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic compare and exchange with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ * @old: pointer to ${int} value to compare with
+ * @new: ${int} value to assign
+ *
+ * If (@v == @old), atomically updates @v to @new with ${desc_order} ordering.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: @true if the exchange occurred, @false otherwise.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/xchg b/scripts/atomic/kerneldoc/xchg
new file mode 100644
index 000000000..75f04c085
--- /dev/null
+++ b/scripts/atomic/kerneldoc/xchg
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic exchange with ${desc_order} ordering
+ * @v: pointer to ${atomic}_t
+ * @new: ${int} value to assign
+ *
+ * Atomically updates @v to @new with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * Return: The original value of @v.
+ */
+EOF
diff --git a/scripts/atomic/kerneldoc/xor b/scripts/atomic/kerneldoc/xor
new file mode 100644
index 000000000..8837270f2
--- /dev/null
+++ b/scripts/atomic/kerneldoc/xor
@@ -0,0 +1,13 @@
+cat <<EOF
+/**
+ * ${class}${atomicname}() - atomic bitwise XOR with ${desc_order} ordering
+ * @i: ${int} value
+ * @v: pointer to ${atomic}_t
+ *
+ * Atomically updates @v to (@v ^ @i) with ${desc_order} ordering.
+ *
+ * ${desc_noinstr}
+ *
+ * ${desc_return}
+ */
+EOF
-- 
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