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![Philippe Mathieu-Daudé](/assets/img/avatar_default.png)
Since commit 292e13142d
, dma_buf_rw() returns a MemTxResult type.
Do not discard it, return it to the caller. Pass the previously
returned value (the QEMUSGList residual size, which was rarely used)
as an optional argument.
With this new API, SCSIRequest::residual might now be accessed via
a pointer. Since the size_t type does not have the same size on
32 and 64-bit host architectures, convert it to a uint64_t, which
is big enough to hold the residual size, and the type is constant
on both 32/64-bit hosts.
Update the few dma_buf_read() / dma_buf_write() callers to the new
API.
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220117125130.131828-1-f4bug@amsat.org>
325 lines
12 KiB
C
325 lines
12 KiB
C
/*
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* DMA helper functions
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*
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* Copyright (c) 2009, 2020 Red Hat
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*
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* This work is licensed under the terms of the GNU General Public License
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* (GNU GPL), version 2 or later.
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*/
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#ifndef DMA_H
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#define DMA_H
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#include "exec/memory.h"
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#include "exec/address-spaces.h"
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#include "block/block.h"
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#include "block/accounting.h"
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typedef enum {
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DMA_DIRECTION_TO_DEVICE = 0,
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DMA_DIRECTION_FROM_DEVICE = 1,
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} DMADirection;
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/*
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* When an IOMMU is present, bus addresses become distinct from
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* CPU/memory physical addresses and may be a different size. Because
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* the IOVA size depends more on the bus than on the platform, we more
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* or less have to treat these as 64-bit always to cover all (or at
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* least most) cases.
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*/
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typedef uint64_t dma_addr_t;
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#define DMA_ADDR_BITS 64
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#define DMA_ADDR_FMT "%" PRIx64
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typedef struct ScatterGatherEntry ScatterGatherEntry;
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struct QEMUSGList {
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ScatterGatherEntry *sg;
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int nsg;
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int nalloc;
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dma_addr_t size;
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DeviceState *dev;
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AddressSpace *as;
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};
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static inline void dma_barrier(AddressSpace *as, DMADirection dir)
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{
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/*
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* This is called before DMA read and write operations
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* unless the _relaxed form is used and is responsible
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* for providing some sane ordering of accesses vs
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* concurrently running VCPUs.
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*
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* Users of map(), unmap() or lower level st/ld_*
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* operations are responsible for providing their own
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* ordering via barriers.
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*
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* This primitive implementation does a simple smp_mb()
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* before each operation which provides pretty much full
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* ordering.
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*
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* A smarter implementation can be devised if needed to
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* use lighter barriers based on the direction of the
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* transfer, the DMA context, etc...
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*/
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smp_mb();
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}
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/* Checks that the given range of addresses is valid for DMA. This is
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* useful for certain cases, but usually you should just use
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* dma_memory_{read,write}() and check for errors */
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static inline bool dma_memory_valid(AddressSpace *as,
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dma_addr_t addr, dma_addr_t len,
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DMADirection dir, MemTxAttrs attrs)
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{
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return address_space_access_valid(as, addr, len,
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dir == DMA_DIRECTION_FROM_DEVICE,
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attrs);
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}
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static inline MemTxResult dma_memory_rw_relaxed(AddressSpace *as,
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dma_addr_t addr,
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void *buf, dma_addr_t len,
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DMADirection dir,
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MemTxAttrs attrs)
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{
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return address_space_rw(as, addr, attrs,
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buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
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}
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static inline MemTxResult dma_memory_read_relaxed(AddressSpace *as,
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dma_addr_t addr,
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void *buf, dma_addr_t len)
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{
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return dma_memory_rw_relaxed(as, addr, buf, len,
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DMA_DIRECTION_TO_DEVICE,
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MEMTXATTRS_UNSPECIFIED);
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}
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static inline MemTxResult dma_memory_write_relaxed(AddressSpace *as,
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dma_addr_t addr,
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const void *buf,
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dma_addr_t len)
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{
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return dma_memory_rw_relaxed(as, addr, (void *)buf, len,
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DMA_DIRECTION_FROM_DEVICE,
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MEMTXATTRS_UNSPECIFIED);
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}
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/**
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* dma_memory_rw: Read from or write to an address space from DMA controller.
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*
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* Return a MemTxResult indicating whether the operation succeeded
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* or failed (eg unassigned memory, device rejected the transaction,
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* IOMMU fault).
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*
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* @as: #AddressSpace to be accessed
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* @addr: address within that address space
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* @buf: buffer with the data transferred
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* @len: the number of bytes to read or write
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* @dir: indicates the transfer direction
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* @attrs: memory transaction attributes
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*/
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static inline MemTxResult dma_memory_rw(AddressSpace *as, dma_addr_t addr,
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void *buf, dma_addr_t len,
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DMADirection dir, MemTxAttrs attrs)
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{
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dma_barrier(as, dir);
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return dma_memory_rw_relaxed(as, addr, buf, len, dir, attrs);
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}
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/**
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* dma_memory_read: Read from an address space from DMA controller.
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*
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* Return a MemTxResult indicating whether the operation succeeded
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* or failed (eg unassigned memory, device rejected the transaction,
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* IOMMU fault). Called within RCU critical section.
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*
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* @as: #AddressSpace to be accessed
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* @addr: address within that address space
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* @buf: buffer with the data transferred
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* @len: length of the data transferred
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* @attrs: memory transaction attributes
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*/
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static inline MemTxResult dma_memory_read(AddressSpace *as, dma_addr_t addr,
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void *buf, dma_addr_t len,
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MemTxAttrs attrs)
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{
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return dma_memory_rw(as, addr, buf, len,
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DMA_DIRECTION_TO_DEVICE, attrs);
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}
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/**
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* address_space_write: Write to address space from DMA controller.
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*
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* Return a MemTxResult indicating whether the operation succeeded
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* or failed (eg unassigned memory, device rejected the transaction,
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* IOMMU fault).
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*
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* @as: #AddressSpace to be accessed
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* @addr: address within that address space
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* @buf: buffer with the data transferred
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* @len: the number of bytes to write
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* @attrs: memory transaction attributes
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*/
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static inline MemTxResult dma_memory_write(AddressSpace *as, dma_addr_t addr,
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const void *buf, dma_addr_t len,
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MemTxAttrs attrs)
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{
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return dma_memory_rw(as, addr, (void *)buf, len,
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DMA_DIRECTION_FROM_DEVICE, attrs);
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}
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/**
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* dma_memory_set: Fill memory with a constant byte from DMA controller.
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*
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* Return a MemTxResult indicating whether the operation succeeded
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* or failed (eg unassigned memory, device rejected the transaction,
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* IOMMU fault).
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*
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* @as: #AddressSpace to be accessed
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* @addr: address within that address space
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* @c: constant byte to fill the memory
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* @len: the number of bytes to fill with the constant byte
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* @attrs: memory transaction attributes
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*/
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MemTxResult dma_memory_set(AddressSpace *as, dma_addr_t addr,
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uint8_t c, dma_addr_t len, MemTxAttrs attrs);
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/**
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* address_space_map: Map a physical memory region into a host virtual address.
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*
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* May map a subset of the requested range, given by and returned in @plen.
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* May return %NULL and set *@plen to zero(0), if resources needed to perform
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* the mapping are exhausted.
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* Use only for reads OR writes - not for read-modify-write operations.
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*
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* @as: #AddressSpace to be accessed
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* @addr: address within that address space
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* @len: pointer to length of buffer; updated on return
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* @dir: indicates the transfer direction
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* @attrs: memory attributes
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*/
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static inline void *dma_memory_map(AddressSpace *as,
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dma_addr_t addr, dma_addr_t *len,
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DMADirection dir, MemTxAttrs attrs)
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{
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hwaddr xlen = *len;
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void *p;
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p = address_space_map(as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE,
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attrs);
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*len = xlen;
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return p;
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}
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/**
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* address_space_unmap: Unmaps a memory region previously mapped
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* by dma_memory_map()
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*
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* Will also mark the memory as dirty if @dir == %DMA_DIRECTION_FROM_DEVICE.
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* @access_len gives the amount of memory that was actually read or written
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* by the caller.
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*
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* @as: #AddressSpace used
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* @buffer: host pointer as returned by address_space_map()
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* @len: buffer length as returned by address_space_map()
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* @dir: indicates the transfer direction
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* @access_len: amount of data actually transferred
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*/
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static inline void dma_memory_unmap(AddressSpace *as,
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void *buffer, dma_addr_t len,
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DMADirection dir, dma_addr_t access_len)
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{
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address_space_unmap(as, buffer, (hwaddr)len,
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dir == DMA_DIRECTION_FROM_DEVICE, access_len);
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}
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#define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
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static inline MemTxResult ld##_lname##_##_end##_dma(AddressSpace *as, \
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dma_addr_t addr, \
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uint##_bits##_t *pval, \
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MemTxAttrs attrs) \
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{ \
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MemTxResult res = dma_memory_read(as, addr, pval, (_bits) / 8, attrs); \
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_end##_bits##_to_cpus(pval); \
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return res; \
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} \
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static inline MemTxResult st##_sname##_##_end##_dma(AddressSpace *as, \
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dma_addr_t addr, \
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uint##_bits##_t val, \
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MemTxAttrs attrs) \
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{ \
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val = cpu_to_##_end##_bits(val); \
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return dma_memory_write(as, addr, &val, (_bits) / 8, attrs); \
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}
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static inline MemTxResult ldub_dma(AddressSpace *as, dma_addr_t addr,
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uint8_t *val, MemTxAttrs attrs)
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{
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return dma_memory_read(as, addr, val, 1, attrs);
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}
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static inline MemTxResult stb_dma(AddressSpace *as, dma_addr_t addr,
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uint8_t val, MemTxAttrs attrs)
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{
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return dma_memory_write(as, addr, &val, 1, attrs);
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}
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DEFINE_LDST_DMA(uw, w, 16, le);
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DEFINE_LDST_DMA(l, l, 32, le);
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DEFINE_LDST_DMA(q, q, 64, le);
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DEFINE_LDST_DMA(uw, w, 16, be);
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DEFINE_LDST_DMA(l, l, 32, be);
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DEFINE_LDST_DMA(q, q, 64, be);
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#undef DEFINE_LDST_DMA
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struct ScatterGatherEntry {
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dma_addr_t base;
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dma_addr_t len;
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};
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void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
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AddressSpace *as);
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void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
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void qemu_sglist_destroy(QEMUSGList *qsg);
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typedef BlockAIOCB *DMAIOFunc(int64_t offset, QEMUIOVector *iov,
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BlockCompletionFunc *cb, void *cb_opaque,
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void *opaque);
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BlockAIOCB *dma_blk_io(AioContext *ctx,
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QEMUSGList *sg, uint64_t offset, uint32_t align,
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DMAIOFunc *io_func, void *io_func_opaque,
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BlockCompletionFunc *cb, void *opaque, DMADirection dir);
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BlockAIOCB *dma_blk_read(BlockBackend *blk,
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QEMUSGList *sg, uint64_t offset, uint32_t align,
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BlockCompletionFunc *cb, void *opaque);
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BlockAIOCB *dma_blk_write(BlockBackend *blk,
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QEMUSGList *sg, uint64_t offset, uint32_t align,
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BlockCompletionFunc *cb, void *opaque);
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MemTxResult dma_buf_read(void *ptr, dma_addr_t len, dma_addr_t *residual,
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QEMUSGList *sg, MemTxAttrs attrs);
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MemTxResult dma_buf_write(void *ptr, dma_addr_t len, dma_addr_t *residual,
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QEMUSGList *sg, MemTxAttrs attrs);
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void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
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QEMUSGList *sg, enum BlockAcctType type);
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/**
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* dma_aligned_pow2_mask: Return the address bit mask of the largest
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* power of 2 size less or equal than @end - @start + 1, aligned with @start,
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* and bounded by 1 << @max_addr_bits bits.
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*
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* @start: range start address
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* @end: range end address (greater than @start)
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* @max_addr_bits: max address bits (<= 64)
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*/
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uint64_t dma_aligned_pow2_mask(uint64_t start, uint64_t end,
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int max_addr_bits);
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#endif
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