qemu/include/exec/memattrs.h

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/*
* Memory transaction attributes
*
* Copyright (c) 2015 Linaro Limited.
*
* Authors:
* Peter Maydell <peter.maydell@linaro.org>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#ifndef MEMATTRS_H
#define MEMATTRS_H
/* Every memory transaction has associated with it a set of
* attributes. Some of these are generic (such as the ID of
* the bus master); some are specific to a particular kind of
* bus (such as the ARM Secure/NonSecure bit). We define them
* all as non-overlapping bitfields in a single struct to avoid
* confusion if different parts of QEMU used the same bit for
* different semantics.
*/
typedef struct MemTxAttrs {
/* Bus masters which don't specify any attributes will get this
* (via the MEMTXATTRS_UNSPECIFIED constant), so that we can
* distinguish "all attributes deliberately clear" from
* "didn't specify" if necessary.
*/
unsigned int unspecified:1;
/* ARM/AMBA: TrustZone Secure access
* x86: System Management Mode access
*/
unsigned int secure:1;
/* Memory access is usermode (unprivileged) */
unsigned int user:1;
/* Stream ID (for MSI for example) */
unsigned int stream_id:16;
} MemTxAttrs;
/* Bus masters which don't specify any attributes will get this,
* which has all attribute bits clear except the topmost one
* (so that we can distinguish "all attributes deliberately clear"
* from "didn't specify" if necessary).
*/
#define MEMTXATTRS_UNSPECIFIED ((MemTxAttrs) { .unspecified = 1 })
#endif