cc05c43ad9
Define an API so that devices can register MemoryRegionOps whose read and write callback functions are passed an arbitrary pointer to some transaction attributes and can return a success-or-failure status code. This will allow us to model devices which: * behave differently for ARM Secure/NonSecure memory accesses * behave differently for privileged/unprivileged accesses * may return a transaction failure (causing a guest exception) for erroneous accesses This patch defines the new API and plumbs the attributes parameter through to the memory.c public level functions io_mem_read() and io_mem_write(), where it is currently dummied out. The success/failure response indication is also propagated out to io_mem_read() and io_mem_write(), which retain the old-style boolean true-for-error return. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/*
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* Memory transaction attributes
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*
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* Copyright (c) 2015 Linaro Limited.
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*
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* Authors:
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* Peter Maydell <peter.maydell@linaro.org>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#ifndef MEMATTRS_H
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#define MEMATTRS_H
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/* Every memory transaction has associated with it a set of
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* attributes. Some of these are generic (such as the ID of
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* the bus master); some are specific to a particular kind of
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* bus (such as the ARM Secure/NonSecure bit). We define them
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* all as non-overlapping bitfields in a single struct to avoid
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* confusion if different parts of QEMU used the same bit for
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* different semantics.
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*/
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typedef struct MemTxAttrs {
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/* Bus masters which don't specify any attributes will get this
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* (via the MEMTXATTRS_UNSPECIFIED constant), so that we can
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* distinguish "all attributes deliberately clear" from
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* "didn't specify" if necessary.
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*/
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unsigned int unspecified:1;
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} MemTxAttrs;
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/* Bus masters which don't specify any attributes will get this,
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* which has all attribute bits clear except the topmost one
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* (so that we can distinguish "all attributes deliberately clear"
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* from "didn't specify" if necessary).
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*/
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#define MEMTXATTRS_UNSPECIFIED ((MemTxAttrs) { .unspecified = 1 })
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#endif
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