Re: [Qemu-devel] [PATCH] xhci: Fix some DMA host endian bugs

[David Gibson <dwg@au1.ibm.com>]

On Fri, Nov 02, 2012 at 08:31:23AM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> > +static inline void xhci_dma_write_u32s(XHCIState *xhci, dma_addr_t addr,
> > +                                       uint32_t *buf, size_t len)
> > +{
> > +    int i;
> > +
> > +    for (i = 0; i < (len / sizeof(uint32_t)); i++) {
> > +        buf[i] = cpu_to_le32(buf[i]);
> > +    }
> > +    pci_dma_write(&xhci->pci_dev, addr, buf, len);
> > +}
> 
> I think we should use a temporary buffer here, otherwise you leave the
> values byteswapped in buf which likely has unwanted side effects.

Here's an updated version that uses a temporary buffer.

>From 588a8f874c8d5a658ef95e35164e182a915091db Mon Sep 17 00:00:00 2001
From: David Gibson <david@gibson.dropbear.id.au>
Date: Mon, 5 Nov 2012 14:29:01 +1100
Subject: [PATCH] xhci: Fix some DMA host endian bugs

The xhci device does correct endian switches on the results of some DMAs
but not all.  In particular, there are many DMAs of what are essentially
arrays of 32-bit integers which never get byteswapped.  This causes them
to be interpreted incorrectly on big-endian hosts, since (as per the xhci
spec) these arrays are always little-endian in guest memory.

This patch adds some helper functions to fix these bugs.  This may not be
all the endian bugs in the xhci code, but it's certainly some of them and
the Linux guest xhci driver certainly gets further with these fixes.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

---
v2:
 * Change xhci_dma_write_u32s to use a temporary buffer rather than
altering the given data in place.
---
 hw/usb/hcd-xhci.c |   81 +++++++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 27 deletions(-)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 7b65741..1465685 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -607,6 +607,34 @@ static inline dma_addr_t xhci_mask64(uint64_t addr)
     }
 }
 
+static inline void xhci_dma_read_u32s(XHCIState *xhci, dma_addr_t addr,
+                                      uint32_t *buf, size_t len)
+{
+    int i;
+
+    assert((len % sizeof(uint32_t)) == 0);
+
+    pci_dma_read(&xhci->pci_dev, addr, buf, len);
+
+    for (i = 0; i < (len / sizeof(uint32_t)); i++) {
+        buf[i] = le32_to_cpu(buf[i]);
+    }
+}
+
+static inline void xhci_dma_write_u32s(XHCIState *xhci, dma_addr_t addr,
+                                       uint32_t *buf, size_t len)
+{
+    int i;
+    uint32_t tmp[len / sizeof(uint32_t)];
+
+    assert((len % sizeof(uint32_t)) == 0);
+
+    for (i = 0; i < (len / sizeof(uint32_t)); i++) {
+        tmp[i] = cpu_to_le32(buf[i]);
+    }
+    pci_dma_write(&xhci->pci_dev, addr, tmp, len);
+}
+
 static XHCIPort *xhci_lookup_port(XHCIState *xhci, struct USBPort *uport)
 {
     int index;
@@ -1018,14 +1046,14 @@ static void xhci_set_ep_state(XHCIState *xhci, XHCIEPContext *epctx,
 {
     uint32_t ctx[5];
 
-    pci_dma_read(&xhci->pci_dev, epctx->pctx, ctx, sizeof(ctx));
+    xhci_dma_read_u32s(xhci, epctx->pctx, ctx, sizeof(ctx));
     ctx[0] &= ~EP_STATE_MASK;
     ctx[0] |= state;
     ctx[2] = epctx->ring.dequeue | epctx->ring.ccs;
     ctx[3] = (epctx->ring.dequeue >> 16) >> 16;
     DPRINTF("xhci: set epctx: " DMA_ADDR_FMT " state=%d dequeue=%08x%08x\n",
             epctx->pctx, state, ctx[3], ctx[2]);
-    pci_dma_write(&xhci->pci_dev, epctx->pctx, ctx, sizeof(ctx));
+    xhci_dma_write_u32s(xhci, epctx->pctx, ctx, sizeof(ctx));
     epctx->state = state;
 }
 
@@ -1857,14 +1885,14 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
     assert(slotid >= 1 && slotid <= xhci->numslots);
 
     dcbaap = xhci_addr64(xhci->dcbaap_low, xhci->dcbaap_high);
-    pci_dma_read(&xhci->pci_dev, dcbaap + 8*slotid, &poctx, sizeof(poctx));
+    poctx = ldq_le_pci_dma(&xhci->pci_dev, dcbaap + 8*slotid);
     ictx = xhci_mask64(pictx);
-    octx = xhci_mask64(le64_to_cpu(poctx));
+    octx = xhci_mask64(poctx);
 
     DPRINTF("xhci: input context at "DMA_ADDR_FMT"\n", ictx);
     DPRINTF("xhci: output context at "DMA_ADDR_FMT"\n", octx);
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if (ictl_ctx[0] != 0x0 || ictl_ctx[1] != 0x3) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -1872,8 +1900,8 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
         return CC_TRB_ERROR;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx+32, slot_ctx, sizeof(slot_ctx));
-    pci_dma_read(&xhci->pci_dev, ictx+64, ep0_ctx, sizeof(ep0_ctx));
+    xhci_dma_read_u32s(xhci, ictx+32, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, ictx+64, ep0_ctx, sizeof(ep0_ctx));
 
     DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
@@ -1923,8 +1951,8 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
             ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
 
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
-    pci_dma_write(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
 
     return res;
 }
@@ -1957,17 +1985,17 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             }
         }
 
-        pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
         slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
         slot_ctx[3] |= SLOT_ADDRESSED << SLOT_STATE_SHIFT;
         DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
                 slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
-        pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
         return CC_SUCCESS;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if ((ictl_ctx[0] & 0x3) != 0x0 || (ictl_ctx[1] & 0x3) != 0x1) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -1975,8 +2003,8 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
         return CC_TRB_ERROR;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx+32, islot_ctx, sizeof(islot_ctx));
-    pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, ictx+32, islot_ctx, sizeof(islot_ctx));
+    xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     if (SLOT_STATE(slot_ctx[3]) < SLOT_ADDRESSED) {
         fprintf(stderr, "xhci: invalid slot state %08x\n", slot_ctx[3]);
@@ -1988,8 +2016,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             xhci_disable_ep(xhci, slotid, i);
         }
         if (ictl_ctx[1] & (1<<i)) {
-            pci_dma_read(&xhci->pci_dev, ictx+32+(32*i), ep_ctx,
-                         sizeof(ep_ctx));
+            xhci_dma_read_u32s(xhci, ictx+32+(32*i), ep_ctx, sizeof(ep_ctx));
             DPRINTF("xhci: input ep%d.%d context: %08x %08x %08x %08x %08x\n",
                     i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
                     ep_ctx[3], ep_ctx[4]);
@@ -2001,7 +2028,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             DPRINTF("xhci: output ep%d.%d context: %08x %08x %08x %08x %08x\n",
                     i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
                     ep_ctx[3], ep_ctx[4]);
-            pci_dma_write(&xhci->pci_dev, octx+(32*i), ep_ctx, sizeof(ep_ctx));
+            xhci_dma_write_u32s(xhci, octx+(32*i), ep_ctx, sizeof(ep_ctx));
         }
     }
 
@@ -2013,7 +2040,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
 
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     return CC_SUCCESS;
 }
@@ -2038,7 +2065,7 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: input context at "DMA_ADDR_FMT"\n", ictx);
     DPRINTF("xhci: output context at "DMA_ADDR_FMT"\n", octx);
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if (ictl_ctx[0] != 0x0 || ictl_ctx[1] & ~0x3) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -2047,12 +2074,12 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
     }
 
     if (ictl_ctx[1] & 0x1) {
-        pci_dma_read(&xhci->pci_dev, ictx+32, islot_ctx, sizeof(islot_ctx));
+        xhci_dma_read_u32s(xhci, ictx+32, islot_ctx, sizeof(islot_ctx));
 
         DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
                 islot_ctx[0], islot_ctx[1], islot_ctx[2], islot_ctx[3]);
 
-        pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
         slot_ctx[1] &= ~0xFFFF; /* max exit latency */
         slot_ctx[1] |= islot_ctx[1] & 0xFFFF;
@@ -2062,17 +2089,17 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
         DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
                 slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
 
-        pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
     }
 
     if (ictl_ctx[1] & 0x2) {
-        pci_dma_read(&xhci->pci_dev, ictx+64, iep0_ctx, sizeof(iep0_ctx));
+        xhci_dma_read_u32s(xhci, ictx+64, iep0_ctx, sizeof(iep0_ctx));
 
         DPRINTF("xhci: input ep0 context: %08x %08x %08x %08x %08x\n",
                 iep0_ctx[0], iep0_ctx[1], iep0_ctx[2],
                 iep0_ctx[3], iep0_ctx[4]);
 
-        pci_dma_read(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+        xhci_dma_read_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
 
         ep0_ctx[1] &= ~0xFFFF0000; /* max packet size*/
         ep0_ctx[1] |= iep0_ctx[1] & 0xFFFF0000;
@@ -2080,7 +2107,7 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
         DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
                 ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
 
-        pci_dma_write(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+        xhci_dma_write_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
     }
 
     return CC_SUCCESS;
@@ -2105,12 +2132,12 @@ static TRBCCode xhci_reset_slot(XHCIState *xhci, unsigned int slotid)
         }
     }
 
-    pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
     slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
     slot_ctx[3] |= SLOT_DEFAULT << SLOT_STATE_SHIFT;
     DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     return CC_SUCCESS;
 }
-- 
1.7.10.4



-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson