From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson 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 Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/input/misc/ibm-panel.c | 196 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 196 insertions(+) create mode 100644 drivers/input/misc/ibm-panel.c (limited to 'drivers/input/misc/ibm-panel.c') diff --git a/drivers/input/misc/ibm-panel.c b/drivers/input/misc/ibm-panel.c new file mode 100644 index 000000000..aa48f62d7 --- /dev/null +++ b/drivers/input/misc/ibm-panel.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) IBM Corporation 2020 + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define DEVICE_NAME "ibm-panel" +#define PANEL_KEYCODES_COUNT 3 + +struct ibm_panel { + u8 idx; + u8 command[11]; + u32 keycodes[PANEL_KEYCODES_COUNT]; + spinlock_t lock; /* protects writes to idx and command */ + struct input_dev *input; +}; + +static u8 ibm_panel_calculate_checksum(struct ibm_panel *panel) +{ + u8 chksum; + u16 sum = 0; + unsigned int i; + + for (i = 0; i < sizeof(panel->command) - 1; ++i) { + sum += panel->command[i]; + if (sum & 0xff00) { + sum &= 0xff; + sum++; + } + } + + chksum = sum & 0xff; + chksum = ~chksum; + chksum++; + + return chksum; +} + +static void ibm_panel_process_command(struct ibm_panel *panel) +{ + u8 button; + u8 chksum; + + if (panel->command[0] != 0xff && panel->command[1] != 0xf0) { + dev_dbg(&panel->input->dev, "command invalid: %02x %02x\n", + panel->command[0], panel->command[1]); + return; + } + + chksum = ibm_panel_calculate_checksum(panel); + if (chksum != panel->command[sizeof(panel->command) - 1]) { + dev_dbg(&panel->input->dev, + "command failed checksum: %u != %u\n", chksum, + panel->command[sizeof(panel->command) - 1]); + return; + } + + button = panel->command[2] & 0xf; + if (button < PANEL_KEYCODES_COUNT) { + input_report_key(panel->input, panel->keycodes[button], + !(panel->command[2] & 0x80)); + input_sync(panel->input); + } else { + dev_dbg(&panel->input->dev, "unknown button %u\n", + button); + } +} + +static int ibm_panel_i2c_slave_cb(struct i2c_client *client, + enum i2c_slave_event event, u8 *val) +{ + struct ibm_panel *panel = i2c_get_clientdata(client); + + dev_dbg(&panel->input->dev, "event: %u data: %02x\n", event, *val); + + guard(spinlock_irqsave)(&panel->lock); + + switch (event) { + case I2C_SLAVE_STOP: + if (panel->idx == sizeof(panel->command)) + ibm_panel_process_command(panel); + else + dev_dbg(&panel->input->dev, + "command incorrect size %u\n", panel->idx); + fallthrough; + case I2C_SLAVE_WRITE_REQUESTED: + panel->idx = 0; + break; + case I2C_SLAVE_WRITE_RECEIVED: + if (panel->idx < sizeof(panel->command)) + panel->command[panel->idx++] = *val; + else + /* + * The command is too long and therefore invalid, so set the index + * to it's largest possible value. When a STOP is finally received, + * the command will be rejected upon processing. + */ + panel->idx = U8_MAX; + break; + case I2C_SLAVE_READ_REQUESTED: + case I2C_SLAVE_READ_PROCESSED: + *val = 0xff; + break; + default: + break; + } + + return 0; +} + +static int ibm_panel_probe(struct i2c_client *client) +{ + struct ibm_panel *panel; + int i; + int error; + + panel = devm_kzalloc(&client->dev, sizeof(*panel), GFP_KERNEL); + if (!panel) + return -ENOMEM; + + spin_lock_init(&panel->lock); + + panel->input = devm_input_allocate_device(&client->dev); + if (!panel->input) + return -ENOMEM; + + panel->input->name = client->name; + panel->input->id.bustype = BUS_I2C; + + error = device_property_read_u32_array(&client->dev, + "linux,keycodes", + panel->keycodes, + PANEL_KEYCODES_COUNT); + if (error) { + /* + * Use gamepad buttons as defaults for compatibility with + * existing applications. + */ + panel->keycodes[0] = BTN_NORTH; + panel->keycodes[1] = BTN_SOUTH; + panel->keycodes[2] = BTN_SELECT; + } + + for (i = 0; i < PANEL_KEYCODES_COUNT; ++i) + input_set_capability(panel->input, EV_KEY, panel->keycodes[i]); + + error = input_register_device(panel->input); + if (error) { + dev_err(&client->dev, + "Failed to register input device: %d\n", error); + return error; + } + + i2c_set_clientdata(client, panel); + error = i2c_slave_register(client, ibm_panel_i2c_slave_cb); + if (error) { + dev_err(&client->dev, + "Failed to register as i2c slave: %d\n", error); + return error; + } + + return 0; +} + +static void ibm_panel_remove(struct i2c_client *client) +{ + i2c_slave_unregister(client); +} + +static const struct of_device_id ibm_panel_match[] = { + { .compatible = "ibm,op-panel" }, + { } +}; +MODULE_DEVICE_TABLE(of, ibm_panel_match); + +static struct i2c_driver ibm_panel_driver = { + .driver = { + .name = DEVICE_NAME, + .of_match_table = ibm_panel_match, + }, + .probe = ibm_panel_probe, + .remove = ibm_panel_remove, +}; +module_i2c_driver(ibm_panel_driver); + +MODULE_AUTHOR("Eddie James "); +MODULE_DESCRIPTION("IBM Operation Panel Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1