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/usb/serial/empeg.c | 122 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 drivers/usb/serial/empeg.c (limited to 'drivers/usb/serial/empeg.c') diff --git a/drivers/usb/serial/empeg.c b/drivers/usb/serial/empeg.c new file mode 100644 index 000000000..4937575ca --- /dev/null +++ b/drivers/usb/serial/empeg.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * USB Empeg empeg-car player driver + * + * Copyright (C) 2000, 2001 + * Gary Brubaker (xavyer@ix.netcom.com) + * + * Copyright (C) 1999 - 2001 + * Greg Kroah-Hartman (greg@kroah.com) + * + * See Documentation/usb/usb-serial.rst for more information on using this + * driver + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_AUTHOR "Greg Kroah-Hartman , Gary Brubaker " +#define DRIVER_DESC "USB Empeg Mark I/II Driver" + +#define EMPEG_VENDOR_ID 0x084f +#define EMPEG_PRODUCT_ID 0x0001 + +/* function prototypes for an empeg-car player */ +static int empeg_startup(struct usb_serial *serial); +static void empeg_init_termios(struct tty_struct *tty); + +static const struct usb_device_id id_table[] = { + { USB_DEVICE(EMPEG_VENDOR_ID, EMPEG_PRODUCT_ID) }, + { } /* Terminating entry */ +}; + +MODULE_DEVICE_TABLE(usb, id_table); + +static struct usb_serial_driver empeg_device = { + .driver = { + .name = "empeg", + }, + .id_table = id_table, + .num_ports = 1, + .bulk_out_size = 256, + .throttle = usb_serial_generic_throttle, + .unthrottle = usb_serial_generic_unthrottle, + .attach = empeg_startup, + .init_termios = empeg_init_termios, +}; + +static struct usb_serial_driver * const serial_drivers[] = { + &empeg_device, NULL +}; + +static int empeg_startup(struct usb_serial *serial) +{ + int r; + + if (serial->dev->actconfig->desc.bConfigurationValue != 1) { + dev_err(&serial->dev->dev, "active config #%d != 1 ??\n", + serial->dev->actconfig->desc.bConfigurationValue); + return -ENODEV; + } + + r = usb_reset_configuration(serial->dev); + + /* continue on with initialization */ + return r; +} + +static void empeg_init_termios(struct tty_struct *tty) +{ + struct ktermios *termios = &tty->termios; + + /* + * The empeg-car player wants these particular tty settings. + * You could, for example, change the baud rate, however the + * player only supports 115200 (currently), so there is really + * no point in support for changes to the tty settings. + * (at least for now) + * + * The default requirements for this device are: + */ + termios->c_iflag + &= ~(IGNBRK /* disable ignore break */ + | BRKINT /* disable break causes interrupt */ + | PARMRK /* disable mark parity errors */ + | ISTRIP /* disable clear high bit of input characters */ + | INLCR /* disable translate NL to CR */ + | IGNCR /* disable ignore CR */ + | ICRNL /* disable translate CR to NL */ + | IXON); /* disable enable XON/XOFF flow control */ + + termios->c_oflag + &= ~OPOST; /* disable postprocess output characters */ + + termios->c_lflag + &= ~(ECHO /* disable echo input characters */ + | ECHONL /* disable echo new line */ + | ICANON /* disable erase, kill, werase, and rprnt special characters */ + | ISIG /* disable interrupt, quit, and suspend special characters */ + | IEXTEN); /* disable non-POSIX special characters */ + + termios->c_cflag + &= ~(CSIZE /* no size */ + | PARENB /* disable parity bit */ + | CBAUD); /* clear current baud rate */ + + termios->c_cflag + |= CS8; /* character size 8 bits */ + + tty_encode_baud_rate(tty, 115200, 115200); +} + +module_usb_serial_driver(serial_drivers, id_table); + +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1