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, 92 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/trace.h b/drivers/usb/chipidea/trace.h
new file mode 100644
index 000000000..1875419cd
--- /dev/null
+++ b/drivers/usb/chipidea/trace.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Trace support header file for device mode
+ *
+ * Copyright (C) 2020 NXP
+ *
+ * Author: Peter Chen <peter.chen@nxp.com>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM chipidea
+
+#if !defined(__LINUX_CHIPIDEA_TRACE) || defined(TRACE_HEADER_MULTI_READ)
+#define __LINUX_CHIPIDEA_TRACE
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <linux/usb/chipidea.h>
+#include "ci.h"
+#include "udc.h"
+
+#define CHIPIDEA_MSG_MAX	500
+
+void ci_log(struct ci_hdrc *ci, const char *fmt, ...);
+
+TRACE_EVENT(ci_log,
+	TP_PROTO(struct ci_hdrc *ci, struct va_format *vaf),
+	TP_ARGS(ci, vaf),
+	TP_STRUCT__entry(
+		__string(name, dev_name(ci->dev))
+		__vstring(msg, vaf->fmt, vaf->va)
+	),
+	TP_fast_assign(
+		__assign_str(name);
+		__assign_vstr(msg, vaf->fmt, vaf->va);
+	),
+	TP_printk("%s: %s", __get_str(name), __get_str(msg))
+);
+
+DECLARE_EVENT_CLASS(ci_log_trb,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td),
+	TP_STRUCT__entry(
+		__string(name, hwep->name)
+		__field(struct td_node *, td)
+		__field(struct usb_request *, req)
+		__field(dma_addr_t, dma)
+		__field(s32, td_remaining_size)
+		__field(u32, next)
+		__field(u32, token)
+		__field(u32, type)
+	),
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->req = &hwreq->req;
+		__entry->td = td;
+		__entry->dma = td->dma;
+		__entry->td_remaining_size = td->td_remaining_size;
+		__entry->next = le32_to_cpu(td->ptr->next);
+		__entry->token = le32_to_cpu(td->ptr->token);
+		__entry->type = usb_endpoint_type(hwep->ep.desc);
+	),
+	TP_printk("%s: req: %p, td: %p, td_dma_address: %pad, remaining_size: %d, "
+	       "next: %x, total bytes: %d, status: %lx",
+		__get_str(name), __entry->req, __entry->td, &__entry->dma,
+		__entry->td_remaining_size, __entry->next,
+		(int)((__entry->token & TD_TOTAL_BYTES) >> __ffs(TD_TOTAL_BYTES)),
+		__entry->token & TD_STATUS
+	)
+);
+
+DEFINE_EVENT(ci_log_trb, ci_prepare_td,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td)
+);
+
+DEFINE_EVENT(ci_log_trb, ci_complete_td,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td)
+);
+
+#endif /* __LINUX_CHIPIDEA_TRACE */
+
+/* this part must be outside header guard */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>