Revision 32ffa4f71e10009498ae6b54da65ab316db967bd authored by Axel Rasmussen on 19 May 2021, 20:03:33 UTC, committed by Paolo Bonzini on 27 May 2021, 11:45:55 UTC
This is a preparatory commit needed before we can use different kinds of
backing pages for guest memory.

Previously, we used perf_test_args.host_page_size, which is the host's
native page size (commonly 4K). For VM_MEM_SRC_ANONYMOUS this turns out
to be okay, but in a follow-up commit we want to allow using different
kinds of backing memory.

Take VM_MEM_SRC_ANONYMOUS_HUGETLB for example. Without this change, if
we used that backing page type, when we issued a UFFDIO_COPY ioctl we'd
only do so with 4K, rather than the full 2M of a backing hugepage. In
this case, UFFDIO_COPY returns -EINVAL (__mcopy_atomic_hugetlb checks
the size).

Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Message-Id: <20210519200339.829146-5-axelrasmussen@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 25408e5
Raw File
crc32defs.h
/* SPDX-License-Identifier: GPL-2.0 */

/* Try to choose an implementation variant via Kconfig */
#ifdef CONFIG_CRC32_SLICEBY8
# define CRC_LE_BITS 64
# define CRC_BE_BITS 64
#endif
#ifdef CONFIG_CRC32_SLICEBY4
# define CRC_LE_BITS 32
# define CRC_BE_BITS 32
#endif
#ifdef CONFIG_CRC32_SARWATE
# define CRC_LE_BITS 8
# define CRC_BE_BITS 8
#endif
#ifdef CONFIG_CRC32_BIT
# define CRC_LE_BITS 1
# define CRC_BE_BITS 1
#endif

/*
 * How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64.
 * For less performance-sensitive, use 4 or 8 to save table size.
 * For larger systems choose same as CPU architecture as default.
 * This works well on X86_64, SPARC64 systems. This may require some
 * elaboration after experiments with other architectures.
 */
#ifndef CRC_LE_BITS
#  ifdef CONFIG_64BIT
#  define CRC_LE_BITS 64
#  else
#  define CRC_LE_BITS 32
#  endif
#endif
#ifndef CRC_BE_BITS
#  ifdef CONFIG_64BIT
#  define CRC_BE_BITS 64
#  else
#  define CRC_BE_BITS 32
#  endif
#endif

/*
 * Little-endian CRC computation.  Used with serial bit streams sent
 * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
 */
#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
	CRC_LE_BITS & CRC_LE_BITS-1
# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
#endif

/*
 * Big-endian CRC computation.  Used with serial bit streams sent
 * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
 */
#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
	CRC_BE_BITS & CRC_BE_BITS-1
# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
#endif
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