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/crypto/poly1305.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 lib/crypto/poly1305.c (limited to 'lib/crypto/poly1305.c') diff --git a/lib/crypto/poly1305.c b/lib/crypto/poly1305.c new file mode 100644 index 000000000..f313ccc4b --- /dev/null +++ b/lib/crypto/poly1305.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Poly1305 authenticator algorithm, RFC7539 + * + * Copyright (C) 2015 Martin Willi + * + * Based on public domain code by Andrew Moon and Daniel J. Bernstein. + */ + +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_CRYPTO_LIB_POLY1305_ARCH +#include "poly1305.h" /* $(SRCARCH)/poly1305.h */ +#else +#define poly1305_block_init poly1305_block_init_generic +#define poly1305_blocks poly1305_blocks_generic +#define poly1305_emit poly1305_emit_generic +#endif + +void poly1305_init(struct poly1305_desc_ctx *desc, + const u8 key[POLY1305_KEY_SIZE]) +{ + desc->s[0] = get_unaligned_le32(key + 16); + desc->s[1] = get_unaligned_le32(key + 20); + desc->s[2] = get_unaligned_le32(key + 24); + desc->s[3] = get_unaligned_le32(key + 28); + desc->buflen = 0; + poly1305_block_init(&desc->state, key); +} +EXPORT_SYMBOL(poly1305_init); + +void poly1305_update(struct poly1305_desc_ctx *desc, + const u8 *src, unsigned int nbytes) +{ + if (desc->buflen + nbytes >= POLY1305_BLOCK_SIZE) { + unsigned int bulk_len; + + if (desc->buflen) { + unsigned int l = POLY1305_BLOCK_SIZE - desc->buflen; + + memcpy(&desc->buf[desc->buflen], src, l); + src += l; + nbytes -= l; + + poly1305_blocks(&desc->state, desc->buf, + POLY1305_BLOCK_SIZE, 1); + desc->buflen = 0; + } + + bulk_len = round_down(nbytes, POLY1305_BLOCK_SIZE); + nbytes %= POLY1305_BLOCK_SIZE; + + if (bulk_len) { + poly1305_blocks(&desc->state, src, bulk_len, 1); + src += bulk_len; + } + } + if (nbytes) { + memcpy(&desc->buf[desc->buflen], src, nbytes); + desc->buflen += nbytes; + } +} +EXPORT_SYMBOL(poly1305_update); + +void poly1305_final(struct poly1305_desc_ctx *desc, u8 *dst) +{ + if (unlikely(desc->buflen)) { + desc->buf[desc->buflen++] = 1; + memset(desc->buf + desc->buflen, 0, + POLY1305_BLOCK_SIZE - desc->buflen); + poly1305_blocks(&desc->state, desc->buf, POLY1305_BLOCK_SIZE, + 0); + } + + poly1305_emit(&desc->state.h, dst, desc->s); + *desc = (struct poly1305_desc_ctx){}; +} +EXPORT_SYMBOL(poly1305_final); + +#ifdef poly1305_mod_init_arch +static int __init poly1305_mod_init(void) +{ + poly1305_mod_init_arch(); + return 0; +} +subsys_initcall(poly1305_mod_init); + +static void __exit poly1305_mod_exit(void) +{ +} +module_exit(poly1305_mod_exit); +#endif + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Poly1305 authenticator algorithm, RFC7539"); -- cgit v1.3.1