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/video/fbdev/q40fb.c | 151 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 drivers/video/fbdev/q40fb.c (limited to 'drivers/video/fbdev/q40fb.c') diff --git a/drivers/video/fbdev/q40fb.c b/drivers/video/fbdev/q40fb.c new file mode 100644 index 000000000..1ff8fa176 --- /dev/null +++ b/drivers/video/fbdev/q40fb.c @@ -0,0 +1,151 @@ +/* + * linux/drivers/video/q40fb.c -- Q40 frame buffer device + * + * Copyright (C) 2001 + * + * Richard Zidlicky + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive for + * more details. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#define Q40_PHYS_SCREEN_ADDR 0xFE800000 + +static struct fb_fix_screeninfo q40fb_fix = { + .id = "Q40", + .smem_len = 1024*1024, + .type = FB_TYPE_PACKED_PIXELS, + .visual = FB_VISUAL_TRUECOLOR, + .line_length = 1024*2, + .accel = FB_ACCEL_NONE, +}; + +static const struct fb_var_screeninfo q40fb_var = { + .xres = 1024, + .yres = 512, + .xres_virtual = 1024, + .yres_virtual = 512, + .bits_per_pixel = 16, + .red = {6, 5, 0}, + .green = {11, 5, 0}, + .blue = {0, 6, 0}, + .activate = FB_ACTIVATE_NOW, + .height = 230, + .width = 300, + .vmode = FB_VMODE_NONINTERLACED, +}; + +static int q40fb_setcolreg(unsigned regno, unsigned red, unsigned green, + unsigned blue, unsigned transp, + struct fb_info *info) +{ + /* + * Set a single color register. The values supplied have a 16 bit + * magnitude. + * Return != 0 for invalid regno. + */ + + if (regno > 255) + return 1; + red>>=11; + green>>=11; + blue>>=10; + + if (regno < 16) { + ((u32 *)info->pseudo_palette)[regno] = ((red & 31) <<6) | + ((green & 31) << 11) | + (blue & 63); + } + return 0; +} + +static const struct fb_ops q40fb_ops = { + .owner = THIS_MODULE, + FB_DEFAULT_IOMEM_OPS, + .fb_setcolreg = q40fb_setcolreg, +}; + +static int q40fb_probe(struct platform_device *dev) +{ + struct fb_info *info; + + if (!MACH_IS_Q40) + return -ENXIO; + + /* mapped in q40/config.c */ + q40fb_fix.smem_start = Q40_PHYS_SCREEN_ADDR; + + info = framebuffer_alloc(sizeof(u32) * 16, &dev->dev); + if (!info) + return -ENOMEM; + + info->var = q40fb_var; + info->fix = q40fb_fix; + info->fbops = &q40fb_ops; + info->pseudo_palette = info->par; + info->par = NULL; + info->screen_base = (char *) q40fb_fix.smem_start; + + if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) { + framebuffer_release(info); + return -ENOMEM; + } + + master_outb(3, DISPLAY_CONTROL_REG); + + if (register_framebuffer(info) < 0) { + printk(KERN_ERR "Unable to register Q40 frame buffer\n"); + fb_dealloc_cmap(&info->cmap); + framebuffer_release(info); + return -EINVAL; + } + + fb_info(info, "Q40 frame buffer alive and kicking !\n"); + return 0; +} + +static struct platform_driver q40fb_driver = { + .probe = q40fb_probe, + .driver = { + .name = "q40fb", + }, +}; + +static struct platform_device q40fb_device = { + .name = "q40fb", +}; + +static int __init q40fb_init(void) +{ + int ret = 0; + + if (fb_get_options("q40fb", NULL)) + return -ENODEV; + + ret = platform_driver_register(&q40fb_driver); + + if (!ret) { + ret = platform_device_register(&q40fb_device); + if (ret) + platform_driver_unregister(&q40fb_driver); + } + return ret; +} + +module_init(q40fb_init); +MODULE_LICENSE("GPL"); -- cgit v1.3.1