From 66a08cbe6ad1aebec8eecf58b3ba042e19dd1649 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 24 Oct 2012 18:31:15 +0200 Subject: uhci: Verify queue has not been changed by guest 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 Signed-off-by: Gerd Hoffmann --- hw/usb/hcd-uhci.c | 62 ++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 45 insertions(+), 17 deletions(-) (limited to 'hw/usb/hcd-uhci.c') diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c index a8b74bdb66..0984bee4f3 100644 --- a/hw/usb/hcd-uhci.c +++ b/hw/usb/hcd-uhci.c @@ -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); -- cgit v1.2.1