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[Qemu-devel] [PATCH] Improve detection of invalid entries in the async s
From: |
David Ahern |
Subject: |
[Qemu-devel] [PATCH] Improve detection of invalid entries in the async schedule |
Date: |
Sun, 25 Apr 2010 11:48:30 -0600 |
Signed-off-by: David Ahern <address@hidden>
---
hw/usb-ehci.c | 41 +++++++++++++++++++++++++++++------------
1 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
index 29baf74..e2f8e54 100644
--- a/hw/usb-ehci.c
+++ b/hw/usb-ehci.c
@@ -144,7 +144,7 @@
#define NB_MAXINTRATE 8 // Max rate at which controller issues ints
#define NB_PORTS 4 // Number of downstream ports
#define BUFF_SIZE 5*4096 // Max bytes to transfer per transaction
-#define MAX_ITERATIONS 50 // Max number of states before we abort
+#define MAX_ITERATIONS 20 // Max number of QH before we break the loop
#define MAX_QH 100 // Max allowable queue heads in a chain
/* Internal periodic / asynchronous schedule state machine states
@@ -1319,6 +1319,11 @@ static int ehci_state_fetchentry(EHCIState *ehci, int
async, int *state)
}
}
#endif
+ if (entry < 0x1000) {
+ DPRINTF("fetchentry: entry invalid (0x%08x)\n", entry);
+ *state = EST_ACTIVE;
+ goto out;
+ }
/* section 4.8, only QH in async schedule */
if (async && (NLPTR_TYPE_GET(entry) != NLPTR_TYPE_QH)) {
@@ -1348,6 +1353,7 @@ static int ehci_state_fetchentry(EHCIState *ehci, int
async, int *state)
return -1;
}
+out:
return again;
}
@@ -1394,7 +1400,7 @@ static int ehci_state_fetchqh(EHCIState *ehci, int async,
int *state)
*state = EST_HORIZONTALQH;
again = 1;
- } else if (qh->token & QTD_TOKEN_ACTIVE) {
+ } else if ((qh->token & QTD_TOKEN_ACTIVE) && (qh->current_qtd > 0x1000)) {
DPRINTF_ST("FETCHQH: Active, !Halt, execute - fetch qTD\n");
ehci->qtdaddr = qh->current_qtd;
*state = EST_FETCHQTD;
@@ -1499,10 +1505,17 @@ static int ehci_state_fetchqtd(EHCIState *ehci, int
async, int *state)
static int ehci_state_horizqh(EHCIState *ehci, int async, int *state)
{
- ehci->fetch_addr = ehci->qh.next;
- *state = EST_FETCHENTRY;
+ int again = 0;
- return 1;
+ if (ehci->fetch_addr != ehci->qh.next) {
+ ehci->fetch_addr = ehci->qh.next;
+ *state = EST_FETCHENTRY;
+ again = 1;
+ } else {
+ *state = EST_ACTIVE;
+ }
+
+ return again;
}
static int ehci_state_execute(EHCIState *ehci, int async, int *state)
@@ -1682,11 +1695,17 @@ static int ehci_advance_state(EHCIState *ehci,
int iter = 0;
do {
- iter++;
- if (iter > MAX_ITERATIONS) {
- DPRINTF("\n*** advance_state: bailing on MAX ITERATIONS***\n\n");
- state = EST_ACTIVE;
- break;
+ if (state == EST_FETCHQH) {
+ iter++;
+ /* if we are roaming a lot of QH without executing a qTD
+ * something is wrong with the linked list. TO-DO: why is
+ * this hack needed?
+ */
+ if (iter > MAX_ITERATIONS) {
+ DPRINTF("\n*** advance_state: bailing on MAX
ITERATIONS***\n");
+ state = EST_ACTIVE;
+ break;
+ }
}
switch(state) {
case EST_WAITLISTHEAD:
@@ -1723,12 +1742,10 @@ static int ehci_advance_state(EHCIState *ehci,
break;
case EST_EXECUTING:
- iter = 0;
again = ehci_state_executing(ehci, async, &state);
break;
case EST_WRITEBACK:
- iter = 0;
again = ehci_state_writeback(ehci, async, &state);
break;
--
1.6.6.1