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uhci: Verify queue has not been changed by guest

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According to the spec a guest can unlink a qh, and then as soon as frindex
has changed by 1 since the unlink, assume it is idle and re-use it. However
for various reasons, we cannot simply consider a qh as unlinked if we've not
seen it for 1 frame. This means that it is possible for a guest to re-use /
restart the queue while we still see its old state. This patch adds a safety
check for this, and "early" retires queues when they were changed by the guest.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Hans de Goede 2012-10-24 18:31:15 +02:00 committed by Gerd Hoffmann
parent 5ad23e873c
commit 66a08cbe6a
2 changed files with 46 additions and 18 deletions
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62
hw/usb/hcd-uhci.c
View File

@ -105,6 +105,7 @@ struct UHCIAsync {
};
struct UHCIQueue {
uint32_t qh_addr;
uint32_t token;
UHCIState *uhci;
USBEndpoint *ep;
@ -170,20 +171,15 @@ static inline int32_t uhci_queue_token(UHCI_TD *td)
return td->token & 0x7ffff;
}
static UHCIQueue *uhci_queue_get(UHCIState *s, UHCI_TD *td, USBEndpoint *ep)
static UHCIQueue *uhci_queue_new(UHCIState *s, uint32_t qh_addr, UHCI_TD *td,
USBEndpoint *ep)
{
uint32_t token = uhci_queue_token(td);
UHCIQueue *queue;
QTAILQ_FOREACH(queue, &s->queues, next) {
if (queue->token == token) {
return queue;
}
}
queue = g_new0(UHCIQueue, 1);
queue->uhci = s;
queue->token = token;
queue->qh_addr = qh_addr;
queue->token = uhci_queue_token(td);
queue->ep = ep;
QTAILQ_INIT(&queue->asyncs);
QTAILQ_INSERT_HEAD(&s->queues, queue, next);
@ -191,7 +187,7 @@ static UHCIQueue *uhci_queue_get(UHCIState *s, UHCI_TD *td, USBEndpoint *ep)
return queue;
}
static void uhci_queue_free(UHCIQueue *queue)
static void uhci_queue_free(UHCIQueue *queue, const char *reason)
{
UHCIState *s = queue->uhci;
UHCIAsync *async;
@ -201,11 +197,35 @@ static void uhci_queue_free(UHCIQueue *queue)
uhci_async_cancel(async);
}
trace_usb_uhci_queue_del(queue->token);
trace_usb_uhci_queue_del(queue->token, reason);
QTAILQ_REMOVE(&s->queues, queue, next);
g_free(queue);
}
static UHCIQueue *uhci_queue_find(UHCIState *s, UHCI_TD *td)
{
uint32_t token = uhci_queue_token(td);
UHCIQueue *queue;
QTAILQ_FOREACH(queue, &s->queues, next) {
if (queue->token == token) {
return queue;
}
}
return NULL;
}
static bool uhci_queue_verify(UHCIQueue *queue, uint32_t qh_addr, UHCI_TD *td,
uint32_t td_addr, bool queuing)
{
UHCIAsync *first = QTAILQ_FIRST(&queue->asyncs);
return queue->qh_addr == qh_addr &&
queue->token == uhci_queue_token(td) &&
(queuing || !(td->ctrl & TD_CTRL_ACTIVE) || first == NULL ||
first->td_addr == td_addr);
}
static UHCIAsync *uhci_async_alloc(UHCIQueue *queue, uint32_t td_addr)
{
UHCIAsync *async = g_new0(UHCIAsync, 1);
@ -274,7 +294,7 @@ static void uhci_async_validate_end(UHCIState *s)
QTAILQ_FOREACH_SAFE(queue, &s->queues, next, n) {
if (!queue->valid) {
uhci_queue_free(queue);
uhci_queue_free(queue, "validate-end");
}
}
}
@ -295,7 +315,7 @@ static void uhci_async_cancel_all(UHCIState *s)
UHCIQueue *queue, *nq;
QTAILQ_FOREACH_SAFE(queue, &s->queues, next, nq) {
uhci_queue_free(queue);
uhci_queue_free(queue, "cancel-all");
}
}
@ -782,7 +802,7 @@ out:
return err;
}
static int uhci_handle_td(UHCIState *s, UHCIQueue *q,
static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
UHCI_TD *td, uint32_t td_addr, uint32_t *int_mask)
{
UHCIAsync *async;
@ -791,6 +811,14 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q,
bool queuing = (q != NULL);
uint8_t pid = td->token & 0xff;
if (q == NULL) {
q = uhci_queue_find(s, td);
if (q && !uhci_queue_verify(q, qh_addr, td, td_addr, queuing)) {
uhci_queue_free(q, "guest re-used qh");
q = NULL;
}
}
/* Is active ? */
if (!(td->ctrl & TD_CTRL_ACTIVE)) {
/*
@ -825,7 +853,7 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q,
if (q == NULL) {
USBDevice *dev = uhci_find_device(s, (td->token >> 8) & 0x7f);
USBEndpoint *ep = usb_ep_get(dev, pid, (td->token >> 15) & 0xf);
q = uhci_queue_get(s, td, ep);
q = uhci_queue_new(s, qh_addr, td, ep);
}
async = uhci_async_alloc(q, td_addr);
@ -954,7 +982,7 @@ static void uhci_queue_fill(UHCIQueue *q, UHCI_TD *td)
break;
}
trace_usb_uhci_td_queue(plink & ~0xf, ptd.ctrl, ptd.token);
ret = uhci_handle_td(q->uhci, q, &ptd, plink, &int_mask);
ret = uhci_handle_td(q->uhci, q, q->qh_addr, &ptd, plink, &int_mask);
if (ret == TD_RESULT_ASYNC_CONT) {
break;
}
@ -1035,7 +1063,7 @@ static void uhci_process_frame(UHCIState *s)
trace_usb_uhci_td_load(curr_qh & ~0xf, link & ~0xf, td.ctrl, td.token);
old_td_ctrl = td.ctrl;
ret = uhci_handle_td(s, NULL, &td, link, &int_mask);
ret = uhci_handle_td(s, NULL, curr_qh, &td, link, &int_mask);
if (old_td_ctrl != td.ctrl) {
/* update the status bits of the TD */
val = cpu_to_le32(td.ctrl);

2
trace-events
View File

@ -287,7 +287,7 @@ usb_uhci_mmio_writew(uint32_t addr, uint32_t val) "addr 0x%04x, val 0x%04x"
usb_uhci_mmio_readl(uint32_t addr, uint32_t val) "addr 0x%04x, ret 0x%08x"
usb_uhci_mmio_writel(uint32_t addr, uint32_t val) "addr 0x%04x, val 0x%08x"
usb_uhci_queue_add(uint32_t token) "token 0x%x"
usb_uhci_queue_del(uint32_t token) "token 0x%x"
usb_uhci_queue_del(uint32_t token, const char *reason) "token 0x%x: %s"
usb_uhci_packet_add(uint32_t token, uint32_t addr) "token 0x%x, td 0x%x"
usb_uhci_packet_link_async(uint32_t token, uint32_t addr) "token 0x%x, td 0x%x"
usb_uhci_packet_unlink_async(uint32_t token, uint32_t addr) "token 0x%x, td 0x%x"