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/mtd/tests/speedtest.c | 418 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 418 insertions(+) create mode 100644 drivers/mtd/tests/speedtest.c (limited to 'drivers/mtd/tests/speedtest.c') diff --git a/drivers/mtd/tests/speedtest.c b/drivers/mtd/tests/speedtest.c new file mode 100644 index 000000000..075bce32c --- /dev/null +++ b/drivers/mtd/tests/speedtest.c @@ -0,0 +1,418 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2007 Nokia Corporation + * + * Test read and write speed of a MTD device. + * + * Author: Adrian Hunter + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "mtd_test.h" + +static int dev = -EINVAL; +module_param(dev, int, S_IRUGO); +MODULE_PARM_DESC(dev, "MTD device number to use"); + +static int count; +module_param(count, int, S_IRUGO); +MODULE_PARM_DESC(count, "Maximum number of eraseblocks to use " + "(0 means use all)"); + +static struct mtd_info *mtd; +static unsigned char *iobuf; +static unsigned char *bbt; + +static int pgsize; +static int ebcnt; +static int pgcnt; +static int goodebcnt; +static ktime_t start, finish; + +static int multiblock_erase(int ebnum, int blocks) +{ + int err; + struct erase_info ei; + loff_t addr = (loff_t)ebnum * mtd->erasesize; + + memset(&ei, 0, sizeof(struct erase_info)); + ei.addr = addr; + ei.len = mtd->erasesize * blocks; + + err = mtd_erase(mtd, &ei); + if (err) { + pr_err("error %d while erasing EB %d, blocks %d\n", + err, ebnum, blocks); + return err; + } + + return 0; +} + +static int write_eraseblock(int ebnum) +{ + loff_t addr = (loff_t)ebnum * mtd->erasesize; + + return mtdtest_write(mtd, addr, mtd->erasesize, iobuf); +} + +static int write_eraseblock_by_page(int ebnum) +{ + int i, err = 0; + loff_t addr = (loff_t)ebnum * mtd->erasesize; + void *buf = iobuf; + + for (i = 0; i < pgcnt; i++) { + err = mtdtest_write(mtd, addr, pgsize, buf); + if (err) + break; + addr += pgsize; + buf += pgsize; + } + + return err; +} + +static int write_eraseblock_by_2pages(int ebnum) +{ + size_t sz = pgsize * 2; + int i, n = pgcnt / 2, err = 0; + loff_t addr = (loff_t)ebnum * mtd->erasesize; + void *buf = iobuf; + + for (i = 0; i < n; i++) { + err = mtdtest_write(mtd, addr, sz, buf); + if (err) + return err; + addr += sz; + buf += sz; + } + if (pgcnt % 2) + err = mtdtest_write(mtd, addr, pgsize, buf); + + return err; +} + +static int read_eraseblock(int ebnum) +{ + loff_t addr = (loff_t)ebnum * mtd->erasesize; + + return mtdtest_read(mtd, addr, mtd->erasesize, iobuf); +} + +static int read_eraseblock_by_page(int ebnum) +{ + int i, err = 0; + loff_t addr = (loff_t)ebnum * mtd->erasesize; + void *buf = iobuf; + + for (i = 0; i < pgcnt; i++) { + err = mtdtest_read(mtd, addr, pgsize, buf); + if (err) + break; + addr += pgsize; + buf += pgsize; + } + + return err; +} + +static int read_eraseblock_by_2pages(int ebnum) +{ + size_t sz = pgsize * 2; + int i, n = pgcnt / 2, err = 0; + loff_t addr = (loff_t)ebnum * mtd->erasesize; + void *buf = iobuf; + + for (i = 0; i < n; i++) { + err = mtdtest_read(mtd, addr, sz, buf); + if (err) + return err; + addr += sz; + buf += sz; + } + if (pgcnt % 2) + err = mtdtest_read(mtd, addr, pgsize, buf); + + return err; +} + +static inline void start_timing(void) +{ + start = ktime_get(); +} + +static inline void stop_timing(void) +{ + finish = ktime_get(); +} + +static long calc_speed(void) +{ + uint64_t k, us; + + us = ktime_us_delta(finish, start); + if (us == 0) + return 0; + k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000000; + do_div(k, us); + return k; +} + +static int __init mtd_speedtest_init(void) +{ + int err, i, blocks, j, k; + long speed; + uint64_t tmp; + + printk(KERN_INFO "\n"); + printk(KERN_INFO "=================================================\n"); + + if (dev < 0) { + pr_info("Please specify a valid mtd-device via module parameter\n"); + pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n"); + return -EINVAL; + } + + if (count) + pr_info("MTD device: %d count: %d\n", dev, count); + else + pr_info("MTD device: %d\n", dev); + + mtd = get_mtd_device(NULL, dev); + if (IS_ERR(mtd)) { + err = PTR_ERR(mtd); + pr_err("error: cannot get MTD device\n"); + return err; + } + + if (mtd->writesize == 1) { + pr_info("not NAND flash, assume page size is 512 " + "bytes.\n"); + pgsize = 512; + } else + pgsize = mtd->writesize; + + tmp = mtd->size; + do_div(tmp, mtd->erasesize); + ebcnt = tmp; + pgcnt = mtd->erasesize / pgsize; + + pr_info("MTD device size %llu, eraseblock size %u, " + "page size %u, count of eraseblocks %u, pages per " + "eraseblock %u, OOB size %u\n", + (unsigned long long)mtd->size, mtd->erasesize, + pgsize, ebcnt, pgcnt, mtd->oobsize); + + if (count > 0 && count < ebcnt) + ebcnt = count; + + err = -ENOMEM; + iobuf = kmalloc(mtd->erasesize, GFP_KERNEL); + if (!iobuf) + goto out; + + get_random_bytes(iobuf, mtd->erasesize); + + bbt = kzalloc(ebcnt, GFP_KERNEL); + if (!bbt) + goto out; + err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt); + if (err) + goto out; + for (i = 0; i < ebcnt; i++) { + if (!bbt[i]) + goodebcnt++; + } + + err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt); + if (err) + goto out; + + /* Write all eraseblocks, 1 eraseblock at a time */ + pr_info("testing eraseblock write speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = write_eraseblock(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("eraseblock write speed is %ld KiB/s\n", speed); + + /* Read all eraseblocks, 1 eraseblock at a time */ + pr_info("testing eraseblock read speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = read_eraseblock(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("eraseblock read speed is %ld KiB/s\n", speed); + + err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt); + if (err) + goto out; + + /* Write all eraseblocks, 1 page at a time */ + pr_info("testing page write speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = write_eraseblock_by_page(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("page write speed is %ld KiB/s\n", speed); + + /* Read all eraseblocks, 1 page at a time */ + pr_info("testing page read speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = read_eraseblock_by_page(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("page read speed is %ld KiB/s\n", speed); + + err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt); + if (err) + goto out; + + /* Write all eraseblocks, 2 pages at a time */ + pr_info("testing 2 page write speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = write_eraseblock_by_2pages(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("2 page write speed is %ld KiB/s\n", speed); + + /* Read all eraseblocks, 2 pages at a time */ + pr_info("testing 2 page read speed\n"); + start_timing(); + for (i = 0; i < ebcnt; ++i) { + if (bbt[i]) + continue; + err = read_eraseblock_by_2pages(i); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + } + stop_timing(); + speed = calc_speed(); + pr_info("2 page read speed is %ld KiB/s\n", speed); + + /* Erase all eraseblocks */ + pr_info("Testing erase speed\n"); + start_timing(); + err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt); + if (err) + goto out; + stop_timing(); + speed = calc_speed(); + pr_info("erase speed is %ld KiB/s\n", speed); + + /* Multi-block erase all eraseblocks */ + for (k = 1; k < 7; k++) { + blocks = 1 << k; + pr_info("Testing %dx multi-block erase speed\n", + blocks); + start_timing(); + for (i = 0; i < ebcnt; ) { + for (j = 0; j < blocks && (i + j) < ebcnt; j++) + if (bbt[i + j]) + break; + if (j < 1) { + i++; + continue; + } + err = multiblock_erase(i, j); + if (err) + goto out; + + err = mtdtest_relax(); + if (err) + goto out; + + i += j; + } + stop_timing(); + speed = calc_speed(); + pr_info("%dx multi-block erase speed is %ld KiB/s\n", + blocks, speed); + } + pr_info("finished\n"); +out: + kfree(iobuf); + kfree(bbt); + put_mtd_device(mtd); + if (err) + pr_info("error %d occurred\n", err); + printk(KERN_INFO "=================================================\n"); + return err; +} +module_init(mtd_speedtest_init); + +static void __exit mtd_speedtest_exit(void) +{ + return; +} +module_exit(mtd_speedtest_exit); + +MODULE_DESCRIPTION("Speed test module"); +MODULE_AUTHOR("Adrian Hunter"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1