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 --- lib/math/test_div64.c | 330 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 330 insertions(+) create mode 100644 lib/math/test_div64.c (limited to 'lib/math/test_div64.c') diff --git a/lib/math/test_div64.c b/lib/math/test_div64.c new file mode 100644 index 000000000..3cd699b65 --- /dev/null +++ b/lib/math/test_div64.c @@ -0,0 +1,330 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Maciej W. Rozycki + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include + +#include + +#define TEST_DIV64_N_ITER 1024 + +static const u64 test_div64_dividends[] = { + 0x00000000ab275080, + 0x0000000fe73c1959, + 0x000000e54c0a74b1, + 0x00000d4398ff1ef9, + 0x0000a18c2ee1c097, + 0x00079fb80b072e4a, + 0x0072db27380dd689, + 0x0842f488162e2284, + 0xf66745411d8ab063, + 0xfffffffffffffffb, + 0xfffffffffffffffc, + 0xffffffffffffffff, +}; +#define SIZE_DIV64_DIVIDENDS ARRAY_SIZE(test_div64_dividends) + +#define TEST_DIV64_DIVISOR_0 0x00000009 +#define TEST_DIV64_DIVISOR_1 0x0000007c +#define TEST_DIV64_DIVISOR_2 0x00000204 +#define TEST_DIV64_DIVISOR_3 0x0000cb5b +#define TEST_DIV64_DIVISOR_4 0x00010000 +#define TEST_DIV64_DIVISOR_5 0x0008a880 +#define TEST_DIV64_DIVISOR_6 0x003fd3ae +#define TEST_DIV64_DIVISOR_7 0x0b658fac +#define TEST_DIV64_DIVISOR_8 0x80000001 +#define TEST_DIV64_DIVISOR_9 0xdc08b349 +#define TEST_DIV64_DIVISOR_A 0xfffffffe +#define TEST_DIV64_DIVISOR_B 0xffffffff + +static const u32 test_div64_divisors[] = { + TEST_DIV64_DIVISOR_0, + TEST_DIV64_DIVISOR_1, + TEST_DIV64_DIVISOR_2, + TEST_DIV64_DIVISOR_3, + TEST_DIV64_DIVISOR_4, + TEST_DIV64_DIVISOR_5, + TEST_DIV64_DIVISOR_6, + TEST_DIV64_DIVISOR_7, + TEST_DIV64_DIVISOR_8, + TEST_DIV64_DIVISOR_9, + TEST_DIV64_DIVISOR_A, + TEST_DIV64_DIVISOR_B, +}; +#define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors) + +static const struct { + u64 quotient; + u32 remainder; +} test_div64_results[SIZE_DIV64_DIVIDENDS][SIZE_DIV64_DIVISORS] = { + { + { 0x0000000013045e47, 0x00000001 }, + { 0x000000000161596c, 0x00000030 }, + { 0x000000000054e9d4, 0x00000130 }, + { 0x000000000000d776, 0x0000278e }, + { 0x000000000000ab27, 0x00005080 }, + { 0x00000000000013c4, 0x0004ce80 }, + { 0x00000000000002ae, 0x001e143c }, + { 0x000000000000000f, 0x0033e56c }, + { 0x0000000000000001, 0x2b27507f }, + { 0x0000000000000000, 0xab275080 }, + { 0x0000000000000000, 0xab275080 }, + { 0x0000000000000000, 0xab275080 }, + }, { + { 0x00000001c45c02d1, 0x00000000 }, + { 0x0000000020d5213c, 0x00000049 }, + { 0x0000000007e3d65f, 0x000001dd }, + { 0x0000000000140531, 0x000065ee }, + { 0x00000000000fe73c, 0x00001959 }, + { 0x000000000001d637, 0x0004e5d9 }, + { 0x0000000000003fc9, 0x000713bb }, + { 0x0000000000000165, 0x029abe7d }, + { 0x000000000000001f, 0x673c193a }, + { 0x0000000000000012, 0x6e9f7e37 }, + { 0x000000000000000f, 0xe73c1977 }, + { 0x000000000000000f, 0xe73c1968 }, + }, { + { 0x000000197a3a0cf7, 0x00000002 }, + { 0x00000001d9632e5c, 0x00000021 }, + { 0x0000000071c28039, 0x000001cd }, + { 0x000000000120a844, 0x0000b885 }, + { 0x0000000000e54c0a, 0x000074b1 }, + { 0x00000000001a7bb3, 0x00072331 }, + { 0x00000000000397ad, 0x0002c61b }, + { 0x000000000000141e, 0x06ea2e89 }, + { 0x00000000000001ca, 0x4c0a72e7 }, + { 0x000000000000010a, 0xab002ad7 }, + { 0x00000000000000e5, 0x4c0a767b }, + { 0x00000000000000e5, 0x4c0a7596 }, + }, { + { 0x0000017949e37538, 0x00000001 }, + { 0x0000001b62441f37, 0x00000055 }, + { 0x0000000694a3391d, 0x00000085 }, + { 0x0000000010b2a5d2, 0x0000a753 }, + { 0x000000000d4398ff, 0x00001ef9 }, + { 0x0000000001882ec6, 0x0005cbf9 }, + { 0x000000000035333b, 0x0017abdf }, + { 0x00000000000129f1, 0x0ab4520d }, + { 0x0000000000001a87, 0x18ff0472 }, + { 0x0000000000000f6e, 0x8ac0ce9b }, + { 0x0000000000000d43, 0x98ff397f }, + { 0x0000000000000d43, 0x98ff2c3c }, + }, { + { 0x000011f321a74e49, 0x00000006 }, + { 0x0000014d8481d211, 0x0000005b }, + { 0x0000005025cbd92d, 0x000001e3 }, + { 0x00000000cb5e71e3, 0x000043e6 }, + { 0x00000000a18c2ee1, 0x0000c097 }, + { 0x0000000012a88828, 0x00036c97 }, + { 0x000000000287f16f, 0x002c2a25 }, + { 0x00000000000e2cc7, 0x02d581e3 }, + { 0x0000000000014318, 0x2ee07d7f }, + { 0x000000000000bbf4, 0x1ba08c03 }, + { 0x000000000000a18c, 0x2ee303af }, + { 0x000000000000a18c, 0x2ee26223 }, + }, { + { 0x0000d8db8f72935d, 0x00000005 }, + { 0x00000fbd5aed7a2e, 0x00000002 }, + { 0x000003c84b6ea64a, 0x00000122 }, + { 0x0000000998fa8829, 0x000044b7 }, + { 0x000000079fb80b07, 0x00002e4a }, + { 0x00000000e16b20fa, 0x0002a14a }, + { 0x000000001e940d22, 0x00353b2e }, + { 0x0000000000ab40ac, 0x06fba6ba }, + { 0x00000000000f3f70, 0x0af7eeda }, + { 0x000000000008debd, 0x72d98365 }, + { 0x0000000000079fb8, 0x0b166dba }, + { 0x0000000000079fb8, 0x0b0ece02 }, + }, { + { 0x000cc3045b8fc281, 0x00000000 }, + { 0x0000ed1f48b5c9fc, 0x00000079 }, + { 0x000038fb9c63406a, 0x000000e1 }, + { 0x000000909705b825, 0x00000a62 }, + { 0x00000072db27380d, 0x0000d689 }, + { 0x0000000d43fce827, 0x00082b09 }, + { 0x00000001ccaba11a, 0x0037e8dd }, + { 0x000000000a13f729, 0x0566dffd }, + { 0x0000000000e5b64e, 0x3728203b }, + { 0x000000000085a14b, 0x23d36726 }, + { 0x000000000072db27, 0x38f38cd7 }, + { 0x000000000072db27, 0x3880b1b0 }, + }, { + { 0x00eafeb9c993592b, 0x00000001 }, + { 0x00110e5befa9a991, 0x00000048 }, + { 0x00041947b4a1d36a, 0x000000dc }, + { 0x00000a6679327311, 0x0000c079 }, + { 0x00000842f488162e, 0x00002284 }, + { 0x000000f4459740fc, 0x00084484 }, + { 0x0000002122c47bf9, 0x002ca446 }, + { 0x00000000b9936290, 0x004979c4 }, + { 0x000000001085e910, 0x05a83974 }, + { 0x00000000099ca89d, 0x9db446bf }, + { 0x000000000842f488, 0x26b40b94 }, + { 0x000000000842f488, 0x1e71170c }, + }, { + { 0x1b60cece589da1d2, 0x00000001 }, + { 0x01fcb42be1453f5b, 0x0000004f }, + { 0x007a3f2457df0749, 0x0000013f }, + { 0x0001363130e3ec7b, 0x000017aa }, + { 0x0000f66745411d8a, 0x0000b063 }, + { 0x00001c757dfab350, 0x00048863 }, + { 0x000003dc4979c652, 0x00224ea7 }, + { 0x000000159edc3144, 0x06409ab3 }, + { 0x00000001ecce8a7e, 0x30bc25e5 }, + { 0x000000011eadfee3, 0xa99c48a8 }, + { 0x00000000f6674543, 0x0a593ae9 }, + { 0x00000000f6674542, 0x13f1f5a5 }, + }, { + { 0x1c71c71c71c71c71, 0x00000002 }, + { 0x0210842108421084, 0x0000000b }, + { 0x007f01fc07f01fc0, 0x000000fb }, + { 0x00014245eabf1f9a, 0x0000a63d }, + { 0x0000ffffffffffff, 0x0000fffb }, + { 0x00001d913cecc509, 0x0007937b }, + { 0x00000402c70c678f, 0x0005bfc9 }, + { 0x00000016766cb70b, 0x045edf97 }, + { 0x00000001fffffffb, 0x80000000 }, + { 0x0000000129d84b3a, 0xa2e8fe71 }, + { 0x0000000100000001, 0xfffffffd }, + { 0x0000000100000000, 0xfffffffb }, + }, { + { 0x1c71c71c71c71c71, 0x00000003 }, + { 0x0210842108421084, 0x0000000c }, + { 0x007f01fc07f01fc0, 0x000000fc }, + { 0x00014245eabf1f9a, 0x0000a63e }, + { 0x0000ffffffffffff, 0x0000fffc }, + { 0x00001d913cecc509, 0x0007937c }, + { 0x00000402c70c678f, 0x0005bfca }, + { 0x00000016766cb70b, 0x045edf98 }, + { 0x00000001fffffffc, 0x00000000 }, + { 0x0000000129d84b3a, 0xa2e8fe72 }, + { 0x0000000100000002, 0x00000000 }, + { 0x0000000100000000, 0xfffffffc }, + }, { + { 0x1c71c71c71c71c71, 0x00000006 }, + { 0x0210842108421084, 0x0000000f }, + { 0x007f01fc07f01fc0, 0x000000ff }, + { 0x00014245eabf1f9a, 0x0000a641 }, + { 0x0000ffffffffffff, 0x0000ffff }, + { 0x00001d913cecc509, 0x0007937f }, + { 0x00000402c70c678f, 0x0005bfcd }, + { 0x00000016766cb70b, 0x045edf9b }, + { 0x00000001fffffffc, 0x00000003 }, + { 0x0000000129d84b3a, 0xa2e8fe75 }, + { 0x0000000100000002, 0x00000003 }, + { 0x0000000100000001, 0x00000000 }, + }, +}; + +static inline bool test_div64_verify(u64 quotient, u32 remainder, int i, int j) +{ + return (quotient == test_div64_results[i][j].quotient && + remainder == test_div64_results[i][j].remainder); +} + +/* + * This needs to be a macro, because we don't want to rely on the compiler + * to do constant propagation, and `do_div' may take a different path for + * constants, so we do want to verify that as well. + */ +#define test_div64_one(dividend, divisor, i, j) ({ \ + bool result = true; \ + u64 quotient; \ + u32 remainder; \ + \ + quotient = dividend; \ + remainder = do_div(quotient, divisor); \ + if (!test_div64_verify(quotient, remainder, i, j)) { \ + pr_err("ERROR: %016llx / %08x => %016llx,%08x\n", \ + dividend, divisor, quotient, remainder); \ + pr_err("ERROR: expected value => %016llx,%08x\n",\ + test_div64_results[i][j].quotient, \ + test_div64_results[i][j].remainder); \ + result = false; \ + } \ + result; \ +}) + +/* + * Run calculation for the same divisor value expressed as a constant + * and as a variable, so as to verify the implementation for both cases + * should they be handled by different code execution paths. + */ +static bool __init test_div64(void) +{ + u64 dividend; + int i, j; + + for (i = 0; i < SIZE_DIV64_DIVIDENDS; i++) { + dividend = test_div64_dividends[i]; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_0, i, 0)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_1, i, 1)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_2, i, 2)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_3, i, 3)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_4, i, 4)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_5, i, 5)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_6, i, 6)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_7, i, 7)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_8, i, 8)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_9, i, 9)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_A, i, 10)) + return false; + if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_B, i, 11)) + return false; + for (j = 0; j < SIZE_DIV64_DIVISORS; j++) { + if (!test_div64_one(dividend, test_div64_divisors[j], + i, j)) + return false; + } + } + return true; +} + +static int __init test_div64_init(void) +{ + struct timespec64 ts, ts0, ts1; + int i; + + pr_info("Starting 64bit/32bit division and modulo test\n"); + ktime_get_ts64(&ts0); + + for (i = 0; i < TEST_DIV64_N_ITER; i++) + if (!test_div64()) + break; + + ktime_get_ts64(&ts1); + ts = timespec64_sub(ts1, ts0); + pr_info("Completed 64bit/32bit division and modulo test, " + "%llu.%09lus elapsed\n", ts.tv_sec, ts.tv_nsec); + + return 0; +} + +static void __exit test_div64_exit(void) +{ +} + +module_init(test_div64_init); +module_exit(test_div64_exit); + +MODULE_AUTHOR("Maciej W. Rozycki "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("64bit/32bit division and modulo test module"); -- cgit v1.3.1