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/dio/dio.c | 288 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 288 insertions(+) create mode 100644 drivers/dio/dio.c (limited to 'drivers/dio/dio.c') diff --git a/drivers/dio/dio.c b/drivers/dio/dio.c new file mode 100644 index 000000000..7722d9eae --- /dev/null +++ b/drivers/dio/dio.c @@ -0,0 +1,288 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Code to support devices on the DIO and DIO-II bus + * Copyright (C) 05/1998 Peter Maydell + * Copyright (C) 2004 Jochen Friedrich + * + * This code has basically these routines at the moment: + * int dio_find(u_int deviceid) + * Search the list of DIO devices and return the select code + * of the next unconfigured device found that matches the given device ID. + * Note that the deviceid parameter should be the encoded ID. + * This means that framebuffers should pass it as + * DIO_ENCODE_ID(DIO_ID_FBUFFER,DIO_ID2_TOPCAT) + * (or whatever); everybody else just uses DIO_ID_FOOBAR. + * unsigned long dio_scodetophysaddr(int scode) + * Return the physical address corresponding to the given select code. + * int dio_scodetoipl(int scode) + * Every DIO card has a fixed interrupt priority level. This function + * returns it, whatever it is. + * const char *dio_scodetoname(int scode) + * Return a character string describing this board [might be "" if + * not CONFIG_DIO_CONSTANTS] + * void dio_config_board(int scode) mark board as configured in the list + * void dio_unconfig_board(int scode) mark board as no longer configured + * + * This file is based on the way the Amiga port handles Zorro II cards, + * although we aren't so complicated... + */ +#include +#include +#include +#include +#include +#include +#include /* kmalloc() */ +#include +#include /* readb() */ + +struct dio_bus dio_bus = { + .resources = { + /* DIO range */ + { .name = "DIO mem", .start = 0x00600000, .end = 0x007fffff }, + /* DIO-II range */ + { .name = "DIO-II mem", .start = 0x01000000, .end = 0x1fffffff } + }, + .name = "DIO bus" +}; + +/* not a real config option yet! */ +#define CONFIG_DIO_CONSTANTS + +#ifdef CONFIG_DIO_CONSTANTS +/* We associate each numeric ID with an appropriate descriptive string + * using a constant array of these structs. + * FIXME: we should be able to arrange to throw away most of the strings + * using the initdata stuff. Then we wouldn't need to worry about + * carrying them around... + * I think we do this by copying them into newly kmalloc()ed memory and + * marking the names[] array as .initdata ? + */ +struct dioname { + int id; + const char *name; +}; + +/* useful macro */ +#define DIONAME(x) { DIO_ID_##x, DIO_DESC_##x } +#define DIOFBNAME(x) { DIO_ENCODE_ID(DIO_ID_FBUFFER, DIO_ID2_##x), DIO_DESC2_##x } + +static struct dioname names[] = { + DIONAME(DCA0), DIONAME(DCA0REM), DIONAME(DCA1), DIONAME(DCA1REM), + DIONAME(DCM), DIONAME(DCMREM), + DIONAME(LAN), + DIONAME(FHPIB), DIONAME(NHPIB), + DIONAME(SCSI0), DIONAME(SCSI1), DIONAME(SCSI2), DIONAME(SCSI3), + DIONAME(FBUFFER), + DIONAME(PARALLEL), DIONAME(VME), DIONAME(DCL), DIONAME(DCLREM), + DIONAME(MISC0), DIONAME(MISC1), DIONAME(MISC2), DIONAME(MISC3), + DIONAME(MISC4), DIONAME(MISC5), DIONAME(MISC6), DIONAME(MISC7), + DIONAME(MISC8), DIONAME(MISC9), DIONAME(MISC10), DIONAME(MISC11), + DIONAME(MISC12), DIONAME(MISC13), + DIOFBNAME(GATORBOX), DIOFBNAME(TOPCAT), DIOFBNAME(RENAISSANCE), + DIOFBNAME(LRCATSEYE), DIOFBNAME(HRCCATSEYE), DIOFBNAME(HRMCATSEYE), + DIOFBNAME(DAVINCI), DIOFBNAME(XXXCATSEYE), DIOFBNAME(HYPERION), + DIOFBNAME(XGENESIS), DIOFBNAME(TIGER), DIOFBNAME(YGENESIS) +}; + +#undef DIONAME +#undef DIOFBNAME + +static const char unknowndioname[] + = "unknown DIO board, please email linux-m68k@lists.linux-m68k.org"; + +static const char *dio_getname(int id) +{ + /* return pointer to a constant string describing the board with given ID */ + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(names); i++) + if (names[i].id == id) + return names[i].name; + + return unknowndioname; +} + +#else + +static char dio_no_name[] = { 0 }; +#define dio_getname(_id) (dio_no_name) + +#endif /* CONFIG_DIO_CONSTANTS */ + +static void dio_dev_release(struct device *dev) +{ + struct dio_dev *ddev = container_of(dev, typeof(struct dio_dev), dev); + kfree(ddev); +} + +int __init dio_find(int deviceid) +{ + /* Called to find a DIO device before the full bus scan has run. + * Only used by the console driver. + */ + int scode, id; + u_char prid, secid, i; + + for (scode = 0; scode < DIO_SCMAX; scode++) { + void *va; + unsigned long pa; + + if (DIO_SCINHOLE(scode)) + continue; + + pa = dio_scodetophysaddr(scode); + + if (!pa) + continue; + + if (scode < DIOII_SCBASE) + va = (void *)(pa + DIO_VIRADDRBASE); + else + va = ioremap(pa, PAGE_SIZE); + + if (copy_from_kernel_nofault(&i, + (unsigned char *)va + DIO_IDOFF, 1)) { + if (scode >= DIOII_SCBASE) + iounmap(va); + continue; /* no board present at that select code */ + } + + prid = DIO_ID(va); + + if (DIO_NEEDSSECID(prid)) { + secid = DIO_SECID(va); + id = DIO_ENCODE_ID(prid, secid); + } else + id = prid; + + if (id == deviceid) { + if (scode >= DIOII_SCBASE) + iounmap(va); + return scode; + } + } + + return -1; +} + +/* This is the function that scans the DIO space and works out what + * hardware is actually present. + */ +static int __init dio_init(void) +{ + int scode; + int i; + struct dio_dev *dev; + int error; + + if (!MACH_IS_HP300) + return 0; + + pr_info("Scanning for DIO devices...\n"); + + /* Initialize the DIO bus */ + INIT_LIST_HEAD(&dio_bus.devices); + dev_set_name(&dio_bus.dev, "dio"); + error = device_register(&dio_bus.dev); + if (error) { + pr_err("DIO: Error registering dio_bus\n"); + return error; + } + + /* Request all resources */ + dio_bus.num_resources = (hp300_model == HP_320 ? 1 : 2); + for (i = 0; i < dio_bus.num_resources; i++) + request_resource(&iomem_resource, &dio_bus.resources[i]); + + /* Register all devices */ + for (scode = 0; scode < DIO_SCMAX; ++scode) { + u_char prid, secid = 0; /* primary, secondary ID bytes */ + u_char *va; + unsigned long pa; + + if (DIO_SCINHOLE(scode)) + continue; + + pa = dio_scodetophysaddr(scode); + + if (!pa) + continue; + + if (scode < DIOII_SCBASE) + va = (void *)(pa + DIO_VIRADDRBASE); + else + va = ioremap(pa, PAGE_SIZE); + + if (copy_from_kernel_nofault(&i, + (unsigned char *)va + DIO_IDOFF, 1)) { + if (scode >= DIOII_SCBASE) + iounmap(va); + continue; /* no board present at that select code */ + } + + /* Found a board, allocate it an entry in the list */ + dev = kzalloc_obj(struct dio_dev); + if (!dev) { + if (scode >= DIOII_SCBASE) + iounmap(va); + return -ENOMEM; + } + + dev->bus = &dio_bus; + dev->dev.parent = &dio_bus.dev; + dev->dev.bus = &dio_bus_type; + dev->dev.release = dio_dev_release; + dev->scode = scode; + dev->resource.start = pa; + dev->resource.end = pa + DIO_SIZE(scode, va); + dev_set_name(&dev->dev, "%02x", scode); + + /* read the ID byte(s) and encode if necessary. */ + prid = DIO_ID(va); + + if (DIO_NEEDSSECID(prid)) { + secid = DIO_SECID(va); + dev->id = DIO_ENCODE_ID(prid, secid); + } else + dev->id = prid; + + dev->ipl = DIO_IPL(va); + strscpy(dev->name, dio_getname(dev->id)); + if (DIO_NEEDSSECID(prid)) + pr_info("select code %3d: ipl %u: ID %02X:%02X: %s\n", + dev->scode, dev->ipl, prid, secid, dev->name); + else + pr_info("select code %3d: ipl %u: ID %02X: %s\n", + dev->scode, dev->ipl, prid, dev->name); + + if (scode >= DIOII_SCBASE) + iounmap(va); + error = device_register(&dev->dev); + if (error) { + pr_err("DIO: Error registering device %s\n", dev->name); + put_device(&dev->dev); + continue; + } + error = dio_create_sysfs_dev_files(dev); + if (error) + dev_err(&dev->dev, "Error creating sysfs files\n"); + } + return 0; +} + +subsys_initcall(dio_init); + +/* Bear in mind that this is called in the very early stages of initialisation + * in order to get the address of the serial port for the console... + */ +unsigned long dio_scodetophysaddr(int scode) +{ + if (scode >= DIOII_SCBASE) + return (DIOII_BASE + (scode - 132) * DIOII_DEVSIZE); + else if (scode > DIO_SCMAX || scode < 0) + return 0; + else if (DIO_SCINHOLE(scode)) + return 0; + + return (DIO_BASE + scode * DIO_DEVSIZE); +} -- cgit v1.3.1