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, 313 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c
new file mode 100644
index 000000000..e72c43615
--- /dev/null
+++ b/drivers/usb/chipidea/debug.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/phy.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/otg-fsm.h>
+#include <linux/usb/chipidea.h>
+
+#include "ci.h"
+#include "udc.h"
+#include "bits.h"
+#include "otg.h"
+
+/*
+ * ci_device_show: prints information about device capabilities and status
+ */
+static int ci_device_show(struct seq_file *s, void *data)
+{
+	struct ci_hdrc *ci = s->private;
+	struct usb_gadget *gadget = &ci->gadget;
+
+	seq_printf(s, "speed             = %d\n", gadget->speed);
+	seq_printf(s, "max_speed         = %d\n", gadget->max_speed);
+	seq_printf(s, "is_otg            = %d\n", gadget->is_otg);
+	seq_printf(s, "is_a_peripheral   = %d\n", gadget->is_a_peripheral);
+	seq_printf(s, "b_hnp_enable      = %d\n", gadget->b_hnp_enable);
+	seq_printf(s, "a_hnp_support     = %d\n", gadget->a_hnp_support);
+	seq_printf(s, "a_alt_hnp_support = %d\n", gadget->a_alt_hnp_support);
+	seq_printf(s, "name              = %s\n",
+		   (gadget->name ? gadget->name : ""));
+
+	if (!ci->driver)
+		return 0;
+
+	seq_printf(s, "gadget function   = %s\n",
+		       (ci->driver->function ? ci->driver->function : ""));
+	seq_printf(s, "gadget max speed  = %d\n", ci->driver->max_speed);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ci_device);
+
+/*
+ * ci_port_test_show: reads port test mode
+ */
+static int ci_port_test_show(struct seq_file *s, void *data)
+{
+	struct ci_hdrc *ci = s->private;
+	unsigned long flags;
+	unsigned mode;
+
+	pm_runtime_get_sync(ci->dev);
+	spin_lock_irqsave(&ci->lock, flags);
+	mode = hw_port_test_get(ci);
+	spin_unlock_irqrestore(&ci->lock, flags);
+	pm_runtime_put_sync(ci->dev);
+
+	seq_printf(s, "mode = %u\n", mode);
+
+	return 0;
+}
+
+/*
+ * ci_port_test_write: writes port test mode
+ */
+static ssize_t ci_port_test_write(struct file *file, const char __user *ubuf,
+				  size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct ci_hdrc *ci = s->private;
+	unsigned long flags;
+	unsigned mode;
+	char buf[32];
+	int ret;
+
+	count = min_t(size_t, sizeof(buf) - 1, count);
+	if (copy_from_user(buf, ubuf, count))
+		return -EFAULT;
+
+	/* sscanf requires a zero terminated string */
+	buf[count] = '\0';
+
+	if (sscanf(buf, "%u", &mode) != 1)
+		return -EINVAL;
+
+	if (mode > 255)
+		return -EBADRQC;
+
+	pm_runtime_get_sync(ci->dev);
+	spin_lock_irqsave(&ci->lock, flags);
+	ret = hw_port_test_set(ci, mode);
+	spin_unlock_irqrestore(&ci->lock, flags);
+	pm_runtime_put_sync(ci->dev);
+
+	return ret ? ret : count;
+}
+
+static int ci_port_test_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ci_port_test_show, inode->i_private);
+}
+
+static const struct file_operations ci_port_test_fops = {
+	.open		= ci_port_test_open,
+	.write		= ci_port_test_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+/*
+ * ci_qheads_show: DMA contents of all queue heads
+ */
+static int ci_qheads_show(struct seq_file *s, void *data)
+{
+	struct ci_hdrc *ci = s->private;
+	unsigned long flags;
+	unsigned i, j;
+
+	if (ci->role != CI_ROLE_GADGET) {
+		seq_printf(s, "not in gadget mode\n");
+		return 0;
+	}
+
+	spin_lock_irqsave(&ci->lock, flags);
+	for (i = 0; i < ci->hw_ep_max/2; i++) {
+		struct ci_hw_ep *hweprx = &ci->ci_hw_ep[i];
+		struct ci_hw_ep *hweptx =
+			&ci->ci_hw_ep[i + ci->hw_ep_max/2];
+		seq_printf(s, "EP=%02i: RX=%08X TX=%08X\n",
+			   i, (u32)hweprx->qh.dma, (u32)hweptx->qh.dma);
+		for (j = 0; j < (sizeof(struct ci_hw_qh)/sizeof(u32)); j++)
+			seq_printf(s, " %04X:    %08X    %08X\n", j,
+				   *((u32 *)hweprx->qh.ptr + j),
+				   *((u32 *)hweptx->qh.ptr + j));
+	}
+	spin_unlock_irqrestore(&ci->lock, flags);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ci_qheads);
+
+/*
+ * ci_requests_show: DMA contents of all requests currently queued (all endpts)
+ */
+static int ci_requests_show(struct seq_file *s, void *data)
+{
+	struct ci_hdrc *ci = s->private;
+	unsigned long flags;
+	struct ci_hw_req *req = NULL;
+	struct td_node *node, *tmpnode;
+	unsigned i, j, qsize = sizeof(struct ci_hw_td)/sizeof(u32);
+
+	if (ci->role != CI_ROLE_GADGET) {
+		seq_printf(s, "not in gadget mode\n");
+		return 0;
+	}
+
+	spin_lock_irqsave(&ci->lock, flags);
+	for (i = 0; i < ci->hw_ep_max; i++)
+		list_for_each_entry(req, &ci->ci_hw_ep[i].qh.queue, queue) {
+			list_for_each_entry_safe(node, tmpnode, &req->tds, td) {
+				seq_printf(s, "EP=%02i: TD=%08X %s\n",
+					   i % (ci->hw_ep_max / 2),
+					   (u32)node->dma,
+					   ((i < ci->hw_ep_max/2) ?
+					   "RX" : "TX"));
+
+				for (j = 0; j < qsize; j++)
+					seq_printf(s, " %04X:    %08X\n", j,
+						   *((u32 *)node->ptr + j));
+			}
+		}
+	spin_unlock_irqrestore(&ci->lock, flags);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ci_requests);
+
+static int ci_otg_show(struct seq_file *s, void *unused)
+{
+	struct ci_hdrc *ci = s->private;
+	struct otg_fsm *fsm;
+
+	if (!ci || !ci_otg_is_fsm_mode(ci))
+		return 0;
+
+	fsm = &ci->fsm;
+
+	/* ------ State ----- */
+	seq_printf(s, "OTG state: %s\n\n",
+			usb_otg_state_string(ci->otg.state));
+
+	/* ------ State Machine Variables ----- */
+	seq_printf(s, "a_bus_drop: %d\n", fsm->a_bus_drop);
+
+	seq_printf(s, "a_bus_req: %d\n", fsm->a_bus_req);
+
+	seq_printf(s, "a_srp_det: %d\n", fsm->a_srp_det);
+
+	seq_printf(s, "a_vbus_vld: %d\n", fsm->a_vbus_vld);
+
+	seq_printf(s, "b_conn: %d\n", fsm->b_conn);
+
+	seq_printf(s, "adp_change: %d\n", fsm->adp_change);
+
+	seq_printf(s, "power_up: %d\n", fsm->power_up);
+
+	seq_printf(s, "a_bus_resume: %d\n", fsm->a_bus_resume);
+
+	seq_printf(s, "a_bus_suspend: %d\n", fsm->a_bus_suspend);
+
+	seq_printf(s, "a_conn: %d\n", fsm->a_conn);
+
+	seq_printf(s, "b_bus_req: %d\n", fsm->b_bus_req);
+
+	seq_printf(s, "b_bus_suspend: %d\n", fsm->b_bus_suspend);
+
+	seq_printf(s, "b_se0_srp: %d\n", fsm->b_se0_srp);
+
+	seq_printf(s, "b_ssend_srp: %d\n", fsm->b_ssend_srp);
+
+	seq_printf(s, "b_sess_vld: %d\n", fsm->b_sess_vld);
+
+	seq_printf(s, "b_srp_done: %d\n", fsm->b_srp_done);
+
+	seq_printf(s, "drv_vbus: %d\n", fsm->drv_vbus);
+
+	seq_printf(s, "loc_conn: %d\n", fsm->loc_conn);
+
+	seq_printf(s, "loc_sof: %d\n", fsm->loc_sof);
+
+	seq_printf(s, "adp_prb: %d\n", fsm->adp_prb);
+
+	seq_printf(s, "id: %d\n", fsm->id);
+
+	seq_printf(s, "protocol: %d\n", fsm->protocol);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ci_otg);
+
+static int ci_registers_show(struct seq_file *s, void *unused)
+{
+	struct ci_hdrc *ci = s->private;
+	u32 tmp_reg;
+
+	if (!ci || ci->in_lpm)
+		return -EPERM;
+
+	/* ------ Registers ----- */
+	tmp_reg = hw_read_intr_enable(ci);
+	seq_printf(s, "USBINTR reg: %08x\n", tmp_reg);
+
+	tmp_reg = hw_read_intr_status(ci);
+	seq_printf(s, "USBSTS reg: %08x\n", tmp_reg);
+
+	tmp_reg = hw_read(ci, OP_USBMODE, ~0);
+	seq_printf(s, "USBMODE reg: %08x\n", tmp_reg);
+
+	tmp_reg = hw_read(ci, OP_USBCMD, ~0);
+	seq_printf(s, "USBCMD reg: %08x\n", tmp_reg);
+
+	tmp_reg = hw_read(ci, OP_PORTSC, ~0);
+	seq_printf(s, "PORTSC reg: %08x\n", tmp_reg);
+
+	if (ci->is_otg) {
+		tmp_reg = hw_read_otgsc(ci, ~0);
+		seq_printf(s, "OTGSC reg: %08x\n", tmp_reg);
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ci_registers);
+
+/**
+ * dbg_create_files: initializes the attribute interface
+ * @ci: device
+ *
+ * This function returns an error code
+ */
+void dbg_create_files(struct ci_hdrc *ci)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir(dev_name(ci->dev), usb_debug_root);
+
+	debugfs_create_file("device", S_IRUGO, dir, ci, &ci_device_fops);
+	debugfs_create_file("port_test", S_IRUGO | S_IWUSR, dir, ci, &ci_port_test_fops);
+	debugfs_create_file("qheads", S_IRUGO, dir, ci, &ci_qheads_fops);
+	debugfs_create_file("requests", S_IRUGO, dir, ci, &ci_requests_fops);
+
+	if (ci_otg_is_fsm_mode(ci))
+		debugfs_create_file("otg", S_IRUGO, dir, ci, &ci_otg_fops);
+
+	debugfs_create_file("registers", S_IRUGO, dir, ci, &ci_registers_fops);
+}
+
+/**
+ * dbg_remove_files: destroys the attribute interface
+ * @ci: device
+ */
+void dbg_remove_files(struct ci_hdrc *ci)
+{
+	debugfs_lookup_and_remove(dev_name(ci->dev), usb_debug_root);
+}