With the IOMMU infrastructure introduced before 1.2, we need to use dma_memory_map() to obtain a qemu pointer to memory from an IO bus address. However, dma_memory_map() alters the given length to reflect the length over which the used DMA translation is valid - which could be either more or less than the requested length. usb_packet_map() does not correctly handle these cases, simply failing if dma_memory_map() alters the requested length. If dma_memory_map() increased the length, we just need to use the requested length for the qemu_iovec_add(). However, if it decreased the length, it means that a single DMA translation is not valid for the whole sglist element, and so we need to loop, splitting it up into multiple iovec entries for each piece with a DMA translation (in practice >2 pieces is unlikely). This patch implements the correct behaviour Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
71 lines
2.3 KiB
C
71 lines
2.3 KiB
C
/*
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* QEMU USB emulation, libhw bits.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "cpu-common.h"
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#include "hw/usb.h"
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#include "dma.h"
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int usb_packet_map(USBPacket *p, QEMUSGList *sgl)
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{
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DMADirection dir = (p->pid == USB_TOKEN_IN) ?
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DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE;
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void *mem;
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int i;
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for (i = 0; i < sgl->nsg; i++) {
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dma_addr_t base = sgl->sg[i].base;
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dma_addr_t len = sgl->sg[i].len;
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while (len) {
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dma_addr_t xlen = len;
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mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &xlen, dir);
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if (!mem) {
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goto err;
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}
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if (xlen > len) {
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xlen = len;
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}
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qemu_iovec_add(&p->iov, mem, xlen);
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len -= xlen;
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base += xlen;
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}
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}
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return 0;
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err:
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usb_packet_unmap(p, sgl);
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return -1;
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}
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void usb_packet_unmap(USBPacket *p, QEMUSGList *sgl)
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{
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DMADirection dir = (p->pid == USB_TOKEN_IN) ?
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DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE;
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int i;
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for (i = 0; i < p->iov.niov; i++) {
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dma_memory_unmap(sgl->dma, p->iov.iov[i].iov_base,
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p->iov.iov[i].iov_len, dir,
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p->iov.iov[i].iov_len);
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}
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}
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