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>

6 files changed, 82 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arc/axs101.txt b/Documentation/devicetree/bindings/arc/axs101.txt
new file mode 100644
index 000000000..48290d517
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/axs101.txt
@@ -0,0 +1,7 @@
+Synopsys DesignWare ARC Software Development Platforms Device Tree Bindings
+---------------------------------------------------------------------------
+
+SDP Main Board with an AXC001 CPU Card hoisting ARC700 core in silicon
+
+Required root node properties:
+    - compatible = "snps,axs101", "snps,arc-sdp";
diff --git a/Documentation/devicetree/bindings/arc/axs103.txt b/Documentation/devicetree/bindings/arc/axs103.txt
new file mode 100644
index 000000000..6eea862e7
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/axs103.txt
@@ -0,0 +1,8 @@
+Synopsys DesignWare ARC Software Development Platforms Device Tree Bindings
+---------------------------------------------------------------------------
+
+SDP Main Board with an AXC003 FPGA Card which can contain various flavours of
+HS38x cores.
+
+Required root node properties:
+    - compatible = "snps,axs103", "snps,arc-sdp";
diff --git a/Documentation/devicetree/bindings/arc/eznps.txt b/Documentation/devicetree/bindings/arc/eznps.txt
new file mode 100644
index 000000000..1aa50c640
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/eznps.txt
@@ -0,0 +1,7 @@
+EZchip NPS Network Processor Platforms Device Tree Bindings
+---------------------------------------------------------------------------
+
+Appliance main board with NPS400 ASIC.
+
+Required root node properties:
+    - compatible = "ezchip,arc-nps";
diff --git a/Documentation/devicetree/bindings/arc/hsdk.txt b/Documentation/devicetree/bindings/arc/hsdk.txt
new file mode 100644
index 000000000..be50654bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/hsdk.txt
@@ -0,0 +1,7 @@
+Synopsys DesignWare ARC HS Development Kit Device Tree Bindings
+---------------------------------------------------------------------------
+
+ARC HSDK Board with quad-core ARC HS38x4 in silicon.
+
+Required root node properties:
+    - compatible = "snps,hsdk";
diff --git a/Documentation/devicetree/bindings/arc/pct.txt b/Documentation/devicetree/bindings/arc/pct.txt
new file mode 100644
index 000000000..4e874d9a3
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/pct.txt
@@ -0,0 +1,20 @@
+* ARC Performance Counters
+
+The ARC700 can be configured with a pipeline performance monitor for counting
+CPU and cache events like cache misses and hits. Like conventional PCT there
+are 100+ hardware conditions dynamically mapped to up to 32 counters
+
+Note that:
+ * The ARC 700 PCT does not support interrupts; although HW events may be
+   counted, the HW events themselves cannot serve as a trigger for a sample.
+
+Required properties:
+
+- compatible : should contain
+	"snps,arc700-pct"
+
+Example:
+
+pmu {
+        compatible = "snps,arc700-pct";
+};
diff --git a/Documentation/devicetree/bindings/arc/snps,archs-pct.yaml b/Documentation/devicetree/bindings/arc/snps,archs-pct.yaml
new file mode 100644
index 000000000..532f7584f
--- /dev/null
+++ b/Documentation/devicetree/bindings/arc/snps,archs-pct.yaml
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arc/snps,archs-pct.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARC HS Performance Counters
+
+maintainers:
+  - Aryabhatta Dey <aryabhattadey35@gmail.com>
+
+description:
+  The ARC HS can be configured with a pipeline performance monitor for counting
+  CPU and cache events like cache misses and hits. Like conventional PCT there
+  are 100+ hardware conditions dynamically mapped to up to 32 counters.
+  It also supports overflow interrupts.
+
+properties:
+  compatible:
+    const: snps,archs-pct
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+additionalProperties: false