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[Qemu-devel] [PATCH 8/8] usb: Fix usb_packet_map() in the presence of IO
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PATCH 8/8] usb: Fix usb_packet_map() in the presence of IOMMUs |
Date: |
Wed, 26 Sep 2012 09:36:11 +0200 |
From: David Gibson <address@hidden>
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 <address@hidden>
Signed-off-by: Gerd Hoffmann <address@hidden>
---
hw/usb/libhw.c | 24 +++++++++++++++---------
1 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/hw/usb/libhw.c b/hw/usb/libhw.c
index c0de30e..703e2d2 100644
--- a/hw/usb/libhw.c
+++ b/hw/usb/libhw.c
@@ -28,19 +28,25 @@ int usb_packet_map(USBPacket *p, QEMUSGList *sgl)
{
DMADirection dir = (p->pid == USB_TOKEN_IN) ?
DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE;
- dma_addr_t len;
void *mem;
int i;
for (i = 0; i < sgl->nsg; i++) {
- len = sgl->sg[i].len;
- mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &len, dir);
- if (!mem) {
- goto err;
- }
- qemu_iovec_add(&p->iov, mem, len);
- if (len != sgl->sg[i].len) {
- goto err;
+ dma_addr_t base = sgl->sg[i].base;
+ dma_addr_t len = sgl->sg[i].len;
+
+ while (len) {
+ dma_addr_t xlen = len;
+ mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &xlen, dir);
+ if (!mem) {
+ goto err;
+ }
+ if (xlen > len) {
+ xlen = len;
+ }
+ qemu_iovec_add(&p->iov, mem, xlen);
+ len -= xlen;
+ base += xlen;
}
}
return 0;
--
1.7.1
- [Qemu-devel] [PULL 0/8] usb patch queue, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 7/8] usb-redir: Adjust pkg-config check for usbredirparser .pc file rename (v2), Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 3/8] xhci: tweak limits, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 1/8] add pc-1.3 machine type, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 5/8] xhci: create a memory region for each port, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 6/8] ehci: Fix interrupt packet MULT handling, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 8/8] usb: Fix usb_packet_map() in the presence of IOMMUs,
Gerd Hoffmann <=
- [Qemu-devel] [PATCH 2/8] compat: turn off msi/msix on xhci for old machine types, Gerd Hoffmann, 2012/09/26
- [Qemu-devel] [PATCH 4/8] xhci: route string & usb hub support, Gerd Hoffmann, 2012/09/26