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/macintosh/ans-lcd.c | 205 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) create mode 100644 drivers/macintosh/ans-lcd.c (limited to 'drivers/macintosh/ans-lcd.c') diff --git a/drivers/macintosh/ans-lcd.c b/drivers/macintosh/ans-lcd.c new file mode 100644 index 000000000..fa904b24a --- /dev/null +++ b/drivers/macintosh/ans-lcd.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * /dev/lcd driver for Apple Network Servers. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include "ans-lcd.h" + +#define ANSLCD_ADDR 0xf301c000 +#define ANSLCD_CTRL_IX 0x00 +#define ANSLCD_DATA_IX 0x10 + +static unsigned long anslcd_short_delay = 80; +static unsigned long anslcd_long_delay = 3280; +static volatile unsigned char __iomem *anslcd_ptr; +static DEFINE_MUTEX(anslcd_mutex); + +#undef DEBUG + +static void +anslcd_write_byte_ctrl ( unsigned char c ) +{ +#ifdef DEBUG + printk(KERN_DEBUG "LCD: CTRL byte: %02x\n",c); +#endif + out_8(anslcd_ptr + ANSLCD_CTRL_IX, c); + switch(c) { + case 1: + case 2: + case 3: + udelay(anslcd_long_delay); break; + default: udelay(anslcd_short_delay); + } +} + +static void +anslcd_write_byte_data ( unsigned char c ) +{ + out_8(anslcd_ptr + ANSLCD_DATA_IX, c); + udelay(anslcd_short_delay); +} + +static ssize_t +anslcd_write( struct file * file, const char __user * buf, + size_t count, loff_t *ppos ) +{ + const char __user *p = buf; + int i; + +#ifdef DEBUG + printk(KERN_DEBUG "LCD: write\n"); +#endif + + if (!access_ok(buf, count)) + return -EFAULT; + + mutex_lock(&anslcd_mutex); + for ( i = *ppos; count > 0; ++i, ++p, --count ) + { + char c; + __get_user(c, p); + anslcd_write_byte_data( c ); + } + mutex_unlock(&anslcd_mutex); + *ppos = i; + return p - buf; +} + +static long +anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + char ch, __user *temp; + long ret = 0; + +#ifdef DEBUG + printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg); +#endif + + mutex_lock(&anslcd_mutex); + + switch ( cmd ) + { + case ANSLCD_CLEAR: + anslcd_write_byte_ctrl ( 0x38 ); + anslcd_write_byte_ctrl ( 0x0f ); + anslcd_write_byte_ctrl ( 0x06 ); + anslcd_write_byte_ctrl ( 0x01 ); + anslcd_write_byte_ctrl ( 0x02 ); + break; + case ANSLCD_SENDCTRL: + temp = (char __user *) arg; + __get_user(ch, temp); + for (; ch; temp++) { /* FIXME: This is ugly, but should work, as a \0 byte is not a valid command code */ + anslcd_write_byte_ctrl ( ch ); + __get_user(ch, temp); + } + break; + case ANSLCD_SETSHORTDELAY: + if (!capable(CAP_SYS_ADMIN)) + ret =-EACCES; + else + anslcd_short_delay=arg; + break; + case ANSLCD_SETLONGDELAY: + if (!capable(CAP_SYS_ADMIN)) + ret = -EACCES; + else + anslcd_long_delay=arg; + break; + default: + ret = -EINVAL; + } + + mutex_unlock(&anslcd_mutex); + return ret; +} + +static int +anslcd_open( struct inode * inode, struct file * file ) +{ + return 0; +} + +const struct file_operations anslcd_fops = { + .write = anslcd_write, + .unlocked_ioctl = anslcd_ioctl, + .open = anslcd_open, + .llseek = default_llseek, +}; + +static struct miscdevice anslcd_dev = { + LCD_MINOR, + "anslcd", + &anslcd_fops +}; + +static const char anslcd_logo[] __initconst = + "********************" /* Line #1 */ + "* LINUX! *" /* Line #3 */ + "* Welcome to *" /* Line #2 */ + "********************"; /* Line #4 */ + +static int __init +anslcd_init(void) +{ + int a; + int retval; + struct device_node* node; + + node = of_find_node_by_name(NULL, "lcd"); + if (!node || !of_node_name_eq(node->parent, "gc")) { + of_node_put(node); + return -ENODEV; + } + of_node_put(node); + + anslcd_ptr = ioremap(ANSLCD_ADDR, 0x20); + + retval = misc_register(&anslcd_dev); + if(retval < 0){ + printk(KERN_INFO "LCD: misc_register failed\n"); + iounmap(anslcd_ptr); + return retval; + } + +#ifdef DEBUG + printk(KERN_DEBUG "LCD: init\n"); +#endif + + mutex_lock(&anslcd_mutex); + anslcd_write_byte_ctrl ( 0x38 ); + anslcd_write_byte_ctrl ( 0x0c ); + anslcd_write_byte_ctrl ( 0x06 ); + anslcd_write_byte_ctrl ( 0x01 ); + anslcd_write_byte_ctrl ( 0x02 ); + for(a=0;a<80;a++) { + anslcd_write_byte_data(anslcd_logo[a]); + } + mutex_unlock(&anslcd_mutex); + return 0; +} + +static void __exit +anslcd_exit(void) +{ + misc_deregister(&anslcd_dev); + iounmap(anslcd_ptr); +} + +module_init(anslcd_init); +module_exit(anslcd_exit); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1