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/md/dm-vdo/numeric.h | 78 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/md/dm-vdo/numeric.h (limited to 'drivers/md/dm-vdo/numeric.h') diff --git a/drivers/md/dm-vdo/numeric.h b/drivers/md/dm-vdo/numeric.h new file mode 100644 index 000000000..f568dc59e --- /dev/null +++ b/drivers/md/dm-vdo/numeric.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef UDS_NUMERIC_H +#define UDS_NUMERIC_H + +#include +#include +#include + +/* + * These utilities encode or decode a number from an offset in a larger data buffer and then + * advance the offset pointer to the next field in the buffer. + */ + +static inline void decode_s64_le(const u8 *buffer, size_t *offset, s64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(s64); +} + +static inline void encode_s64_le(u8 *data, size_t *offset, s64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(s64); +} + +static inline void decode_u64_le(const u8 *buffer, size_t *offset, u64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(u64); +} + +static inline void encode_u64_le(u8 *data, size_t *offset, u64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(u64); +} + +static inline void decode_s32_le(const u8 *buffer, size_t *offset, s32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(s32); +} + +static inline void encode_s32_le(u8 *data, size_t *offset, s32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(s32); +} + +static inline void decode_u32_le(const u8 *buffer, size_t *offset, u32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(u32); +} + +static inline void encode_u32_le(u8 *data, size_t *offset, u32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(u32); +} + +static inline void decode_u16_le(const u8 *buffer, size_t *offset, u16 *decoded) +{ + *decoded = get_unaligned_le16(buffer + *offset); + *offset += sizeof(u16); +} + +static inline void encode_u16_le(u8 *data, size_t *offset, u16 to_encode) +{ + put_unaligned_le16(to_encode, data + *offset); + *offset += sizeof(u16); +} + +#endif /* UDS_NUMERIC_H */ -- cgit v1.3.1