include/exec/memattrs.h

   1 /*
   2  * Memory transaction attributes
   3  *
   4  * Copyright (c) 2015 Linaro Limited.
   5  *
   6  * Authors:
   7  *  Peter Maydell <peter.maydell@linaro.org>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #ifndef MEMATTRS_H
  15 #define MEMATTRS_H
  16
  17 /* Every memory transaction has associated with it a set of
  18  * attributes. Some of these are generic (such as the ID of
  19  * the bus master); some are specific to a particular kind of
  20  * bus (such as the ARM Secure/NonSecure bit). We define them
  21  * all as non-overlapping bitfields in a single struct to avoid
  22  * confusion if different parts of QEMU used the same bit for
  23  * different semantics.
  24  */
  25 typedef struct MemTxAttrs {
  26     /* Bus masters which don't specify any attributes will get this
  27      * (via the MEMTXATTRS_UNSPECIFIED constant), so that we can
  28      * distinguish "all attributes deliberately clear" from
  29      * "didn't specify" if necessary.
  30      */
  31     unsigned int unspecified:1;
  32     /* ARM/AMBA: TrustZone Secure access
  33      * x86: System Management Mode access
  34      */
  35     unsigned int secure:1;
  36     /* Memory access is usermode (unprivileged) */
  37     unsigned int user:1;
  38     /* Requester ID (for MSI for example) */
  39     unsigned int requester_id:16;
  40     /* Invert endianness for this page */
  41     unsigned int byte_swap:1;
  42     /*
  43      * The following are target-specific page-table bits.  These are not
  44      * related to actual memory transactions at all.  However, this structure
  45      * is part of the tlb_fill interface, cached in the cputlb structure,
  46      * and has unused bits.  These fields will be read by target-specific
  47      * helpers using env->iotlb[mmu_idx][tlb_index()].attrs.target_tlb_bitN.
  48      */
  49     unsigned int target_tlb_bit0 : 1;
  50     unsigned int target_tlb_bit1 : 1;
  51     unsigned int target_tlb_bit2 : 1;
  52 } MemTxAttrs;
  53
  54 /* Bus masters which don't specify any attributes will get this,
  55  * which has all attribute bits clear except the topmost one
  56  * (so that we can distinguish "all attributes deliberately clear"
  57  * from "didn't specify" if necessary).
  58  */
  59 #define MEMTXATTRS_UNSPECIFIED ((MemTxAttrs) { .unspecified = 1 })
  60
  61 /* New-style MMIO accessors can indicate that the transaction failed.
  62  * A zero (MEMTX_OK) response means success; anything else is a failure
  63  * of some kind. The memory subsystem will bitwise-OR together results
  64  * if it is synthesizing an operation from multiple smaller accesses.
  65  */
  66 #define MEMTX_OK 0
  67 #define MEMTX_ERROR             (1U << 0) /* device returned an error */
  68 #define MEMTX_DECODE_ERROR      (1U << 1) /* nothing at that address */
  69 typedef uint32_t MemTxResult;
  70
  71 #endif