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, 65 insertions, 0 deletions

diff --git a/drivers/video/fbdev/carminefb.h b/drivers/video/fbdev/carminefb.h
new file mode 100644
index 000000000..c9825481d
--- /dev/null
+++ b/drivers/video/fbdev/carminefb.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CARMINE_CARMINE_H
+#define CARMINE_CARMINE_H
+
+#define CARMINE_MEMORY_BAR	2
+#define CARMINE_CONFIG_BAR	3
+
+#define MAX_DISPLAY	2
+#define CARMINE_DISPLAY_MEM	(800 * 600 * 4)
+#define CARMINE_TOTAL_DISPLAY_MEM	(CARMINE_DISPLAY_MEM * MAX_DISPLAY)
+
+#define CARMINE_USE_DISPLAY0	(1 << 0)
+#define CARMINE_USE_DISPLAY1	(1 << 1)
+
+/*
+ * This values work on the eval card. Custom boards may use different timings,
+ * here an example :)
+ */
+
+/* DRAM initialization values */
+#ifdef CONFIG_FB_CARMINE_DRAM_EVAL
+
+#define CARMINE_DFLT_IP_CLOCK_ENABLE		(0x03ff)
+#define CARMINE_DFLT_IP_DCTL_ADD		(0x05c3)
+#define CARMINE_DFLT_IP_DCTL_MODE		(0x0121)
+#define CARMINE_DFLT_IP_DCTL_EMODE		(0x8000)
+#define CARMINE_DFLT_IP_DCTL_SET_TIME1		(0x4749)
+#define CARMINE_DFLT_IP_DCTL_SET_TIME2		(0x2a22)
+#define CARMINE_DFLT_IP_DCTL_REFRESH		(0x0042)
+#define CARMINE_DFLT_IP_DCTL_STATES		(0x0003)
+#define CARMINE_DFLT_IP_DCTL_RESERVE0		(0x0020)
+#define CARMINE_DFLT_IP_DCTL_FIFO_DEPTH		(0x000f)
+#define CARMINE_DFLT_IP_DCTL_RESERVE2		(0x0000)
+#define CARMINE_DFLT_IP_DCTL_DDRIF1		(0x6646)
+#define CARMINE_DFLT_IP_DCTL_DDRIF2		(0x0055)
+#define CARMINE_DFLT_IP_DCTL_MODE_AFT_RST	(0x0021)
+#define CARMINE_DFLT_IP_DCTL_STATES_AFT_RST	(0x0002)
+#define CARMINE_DFLT_IP_DCTL_IO_CONT0		(0x0555)
+#define CARMINE_DFLT_IP_DCTL_IO_CONT1		(0x0555)
+#define CARMINE_DCTL_DLL_RESET			(1)
+#endif
+
+#ifdef CONFIG_CARMINE_DRAM_CUSTOM
+
+#define CARMINE_DFLT_IP_CLOCK_ENABLE		(0x03ff)
+#define CARMINE_DFLT_IP_DCTL_ADD		(0x03b2)
+#define CARMINE_DFLT_IP_DCTL_MODE		(0x0161)
+#define CARMINE_DFLT_IP_DCTL_EMODE		(0x8000)
+#define CARMINE_DFLT_IP_DCTL_SET_TIME1		(0x2628)
+#define CARMINE_DFLT_IP_DCTL_SET_TIME2		(0x1a09)
+#define CARMINE_DFLT_IP_DCTL_REFRESH		(0x00fe)
+#define CARMINE_DFLT_IP_DCTL_STATES		(0x0003)
+#define CARMINE_DFLT_IP_DCTL_RESERVE0		(0x0020)
+#define CARMINE_DFLT_IP_DCTL_FIFO_DEPTH		(0x000f)
+#define CARMINE_DFLT_IP_DCTL_RESERVE2		(0x0000)
+#define CARMINE_DFLT_IP_DCTL_DDRIF1		(0x0646)
+#define CARMINE_DFLT_IP_DCTL_DDRIF2		(0x55aa)
+#define CARMINE_DFLT_IP_DCTL_MODE_AFT_RST	(0x0061)
+#define CARMINE_DFLT_IP_DCTL_STATES_AFT_RST	(0x0002)
+#define CARMINE_DFLT_IP_DCTL_IO_CONT0		(0x0555)
+#define CARMINE_DFLT_IP_DCTL_IO_CONT1		(0x0555)
+#define CARMINE_DCTL_DLL_RESET			(1)
+#endif
+
+#endif