Merge remote-tracking branch 'remotes/kraxel/tags/pull-usb-20170221-1' into staging

xhci: add qemu-xhci device, some followup cleanups.
ccid: better sanity checking.
ehci: fix memory leak
ohci: bugfixes.

# gpg: Signature made Tue 21 Feb 2017 07:14:35 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/pull-usb-20170221-1:
  usb-ccid: add check message size checks
  usb-ccid: move header size check
  usb-ccid: better bulk_out error handling
  xhci: drop via vendor command handling
  xhci: fix nec vendor quirk handling
  xhci: add qemu xhci controller
  xhci: drop ER_FULL_HACK workaround
  xhci: apply limits to loops
  usb: ohci: limit the number of link eds
  usb: ohci: fix error return code in servicing iso td
  usb: ehci: fix memory leak in ehci

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

9 files changed, 191 insertions, 221 deletions

diff --git a/docs/specs/pci-ids.txt b/docs/specs/pci-ids.txt
index 16fdb0c..95adee0 100644
--- a/docs/specs/pci-ids.txt
+++ b/docs/specs/pci-ids.txt
@@ -61,6 +61,7 @@ PCI devices (other than virtio):
 1b36:0009  PCI Expander Bridge (-device pxb)
 1b36:000a  PCI-PCI bridge (multiseat)
 1b36:000b  PCIe Expander Bridge (-device pxb-pcie)
+1b36:000d  PCI xhci usb host adapter
 
 All these devices are documented in docs/specs.
 
diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 1325ea1..7cd4ed0 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -1001,80 +1001,92 @@ static void ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p)
     CCID_Header *ccid_header;
 
     if (p->iov.size + s->bulk_out_pos > BULK_OUT_DATA_SIZE) {
-        p->status = USB_RET_STALL;
-        return;
+        goto err;
     }
-    ccid_header = (CCID_Header *)s->bulk_out_data;
     usb_packet_copy(p, s->bulk_out_data + s->bulk_out_pos, p->iov.size);
     s->bulk_out_pos += p->iov.size;
-    if (p->iov.size == CCID_MAX_PACKET_SIZE) {
+    if (s->bulk_out_pos < 10) {
+        DPRINTF(s, 1, "%s: header incomplete\n", __func__);
+        goto err;
+    }
+
+    ccid_header = (CCID_Header *)s->bulk_out_data;
+    if ((s->bulk_out_pos - 10 < ccid_header->dwLength) &&
+        (p->iov.size == CCID_MAX_PACKET_SIZE)) {
         DPRINTF(s, D_VERBOSE,
-            "usb-ccid: bulk_in: expecting more packets (%zd/%d)\n",
-            p->iov.size, ccid_header->dwLength);
+                "usb-ccid: bulk_in: expecting more packets (%d/%d)\n",
+                s->bulk_out_pos - 10, ccid_header->dwLength);
         return;
     }
-    if (s->bulk_out_pos < 10) {
+    if (s->bulk_out_pos - 10 != ccid_header->dwLength) {
         DPRINTF(s, 1,
-                "%s: bad USB_TOKEN_OUT length, should be at least 10 bytes\n",
-                __func__);
-    } else {
-        DPRINTF(s, D_MORE_INFO, "%s %x %s\n", __func__,
-                ccid_header->bMessageType,
-                ccid_message_type_to_str(ccid_header->bMessageType));
-        switch (ccid_header->bMessageType) {
-        case CCID_MESSAGE_TYPE_PC_to_RDR_GetSlotStatus:
-            ccid_write_slot_status(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_IccPowerOn:
-            DPRINTF(s, 1, "%s: PowerOn: %d\n", __func__,
+                "usb-ccid: bulk_in: message size mismatch (got %d, expected %d)\n",
+                s->bulk_out_pos - 10, ccid_header->dwLength);
+        goto err;
+    }
+
+    DPRINTF(s, D_MORE_INFO, "%s %x %s\n", __func__,
+            ccid_header->bMessageType,
+            ccid_message_type_to_str(ccid_header->bMessageType));
+    switch (ccid_header->bMessageType) {
+    case CCID_MESSAGE_TYPE_PC_to_RDR_GetSlotStatus:
+        ccid_write_slot_status(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_IccPowerOn:
+        DPRINTF(s, 1, "%s: PowerOn: %d\n", __func__,
                 ((CCID_IccPowerOn *)(ccid_header))->bPowerSelect);
-            s->powered = true;
-            if (!ccid_card_inserted(s)) {
-                ccid_report_error_failed(s, ERROR_ICC_MUTE);
-            }
-            /* atr is written regardless of error. */
-            ccid_write_data_block_atr(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_IccPowerOff:
-            ccid_reset_error_status(s);
-            s->powered = false;
-            ccid_write_slot_status(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_XfrBlock:
-            ccid_on_apdu_from_guest(s, (CCID_XferBlock *)s->bulk_out_data);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_SetParameters:
-            ccid_reset_error_status(s);
-            ccid_set_parameters(s, ccid_header);
-            ccid_write_parameters(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_ResetParameters:
-            ccid_reset_error_status(s);
-            ccid_reset_parameters(s);
-            ccid_write_parameters(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_GetParameters:
-            ccid_reset_error_status(s);
-            ccid_write_parameters(s, ccid_header);
-            break;
-        case CCID_MESSAGE_TYPE_PC_to_RDR_Mechanical:
-            ccid_report_error_failed(s, 0);
-            ccid_write_slot_status(s, ccid_header);
-            break;
-        default:
-            DPRINTF(s, 1,
+        s->powered = true;
+        if (!ccid_card_inserted(s)) {
+            ccid_report_error_failed(s, ERROR_ICC_MUTE);
+        }
+        /* atr is written regardless of error. */
+        ccid_write_data_block_atr(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_IccPowerOff:
+        ccid_reset_error_status(s);
+        s->powered = false;
+        ccid_write_slot_status(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_XfrBlock:
+        ccid_on_apdu_from_guest(s, (CCID_XferBlock *)s->bulk_out_data);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_SetParameters:
+        ccid_reset_error_status(s);
+        ccid_set_parameters(s, ccid_header);
+        ccid_write_parameters(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_ResetParameters:
+        ccid_reset_error_status(s);
+        ccid_reset_parameters(s);
+        ccid_write_parameters(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_GetParameters:
+        ccid_reset_error_status(s);
+        ccid_write_parameters(s, ccid_header);
+        break;
+    case CCID_MESSAGE_TYPE_PC_to_RDR_Mechanical:
+        ccid_report_error_failed(s, 0);
+        ccid_write_slot_status(s, ccid_header);
+        break;
+    default:
+        DPRINTF(s, 1,
                 "handle_data: ERROR: unhandled message type %Xh\n",
                 ccid_header->bMessageType);
-            /*
-             * The caller is expecting the device to respond, tell it we
-             * don't support the operation.
-             */
-            ccid_report_error_failed(s, ERROR_CMD_NOT_SUPPORTED);
-            ccid_write_slot_status(s, ccid_header);
-            break;
-        }
+        /*
+         * The caller is expecting the device to respond, tell it we
+         * don't support the operation.
+         */
+        ccid_report_error_failed(s, ERROR_CMD_NOT_SUPPORTED);
+        ccid_write_slot_status(s, ccid_header);
+        break;
     }
     s->bulk_out_pos = 0;
+    return;
+
+err:
+    p->status = USB_RET_STALL;
+    s->bulk_out_pos = 0;
+    return;
 }
 
 static void ccid_bulk_in_copy_to_guest(USBCCIDState *s, USBPacket *p)
diff --git a/hw/usb/hcd-ehci-pci.c b/hw/usb/hcd-ehci-pci.c
index 5657705..6dedcb8 100644
--- a/hw/usb/hcd-ehci-pci.c
+++ b/hw/usb/hcd-ehci-pci.c
@@ -89,6 +89,14 @@ static void usb_ehci_pci_init(Object *obj)
     usb_ehci_init(s, DEVICE(obj));
 }
 
+static void usb_ehci_pci_finalize(Object *obj)
+{
+    EHCIPCIState *i = PCI_EHCI(obj);
+    EHCIState *s = &i->ehci;
+
+    usb_ehci_finalize(s);
+}
+
 static void usb_ehci_pci_exit(PCIDevice *dev)
 {
     EHCIPCIState *i = PCI_EHCI(dev);
@@ -159,6 +167,7 @@ static const TypeInfo ehci_pci_type_info = {
     .parent = TYPE_PCI_DEVICE,
     .instance_size = sizeof(EHCIPCIState),
     .instance_init = usb_ehci_pci_init,
+    .instance_finalize = usb_ehci_pci_finalize,
     .abstract = true,
     .class_init = ehci_class_init,
 };
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 7622a3a..50ef817 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -2545,6 +2545,11 @@ void usb_ehci_init(EHCIState *s, DeviceState *dev)
                                 &s->mem_ports);
 }
 
+void usb_ehci_finalize(EHCIState *s)
+{
+    usb_packet_cleanup(&s->ipacket);
+}
+
 /*
  * vim: expandtab ts=4
  */
diff --git a/hw/usb/hcd-ehci.h b/hw/usb/hcd-ehci.h
index 3fd7038..938d8aa 100644
--- a/hw/usb/hcd-ehci.h
+++ b/hw/usb/hcd-ehci.h
@@ -323,6 +323,7 @@ struct EHCIState {
 extern const VMStateDescription vmstate_ehci;
 
 void usb_ehci_init(EHCIState *s, DeviceState *dev);
+void usb_ehci_finalize(EHCIState *s);
 void usb_ehci_realize(EHCIState *s, DeviceState *dev, Error **errp);
 void usb_ehci_unrealize(EHCIState *s, DeviceState *dev, Error **errp);
 void ehci_reset(void *opaque);
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index c82a92f..21c93e0 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -42,6 +42,8 @@
 
 #define OHCI_MAX_PORTS 15
 
+#define ED_LINK_LIMIT 4
+
 static int64_t usb_frame_time;
 static int64_t usb_bit_time;
 
@@ -725,7 +727,7 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
     if (ohci_read_iso_td(ohci, addr, &iso_td)) {
         trace_usb_ohci_iso_td_read_failed(addr);
         ohci_die(ohci);
-        return 0;
+        return 1;
     }
 
     starting_frame = OHCI_BM(iso_td.flags, TD_SF);
@@ -1184,7 +1186,7 @@ static int ohci_service_ed_list(OHCIState *ohci, uint32_t head, int completion)
     uint32_t next_ed;
     uint32_t cur;
     int active;
-
+    uint32_t link_cnt = 0;
     active = 0;
 
     if (head == 0)
@@ -1199,6 +1201,11 @@ static int ohci_service_ed_list(OHCIState *ohci, uint32_t head, int completion)
 
         next_ed = ed.next & OHCI_DPTR_MASK;
 
+        if (++link_cnt > ED_LINK_LIMIT) {
+            ohci_die(ohci);
+            return 0;
+        }
+
         if ((ed.head & OHCI_ED_H) || (ed.flags & OHCI_ED_K)) {
             uint32_t addr;
             /* Cancel pending packets for ED that have been paused.  */
diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 54b3901..28dd2f2 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -49,11 +49,10 @@
 
 /* Very pessimistic, let's hope it's enough for all cases */
 #define EV_QUEUE (((3 * 24) + 16) * MAXSLOTS)
-/* Do not deliver ER Full events. NEC's driver does some things not bound
- * to the specs when it gets them */
-#define ER_FULL_HACK
 
 #define TRB_LINK_LIMIT  4
+#define COMMAND_LIMIT   256
+#define TRANSFER_LIMIT  256
 
 #define LEN_CAP         0x40
 #define LEN_OPER        (0x400 + 0x10 * MAXPORTS)
@@ -199,7 +198,6 @@ typedef enum TRBType {
     ER_DEVICE_NOTIFICATION,
     ER_MFINDEX_WRAP,
     /* vendor specific bits */
-    CR_VENDOR_VIA_CHALLENGE_RESPONSE = 48,
     CR_VENDOR_NEC_FIRMWARE_REVISION  = 49,
     CR_VENDOR_NEC_CHALLENGE_RESPONSE = 50,
 } TRBType;
@@ -431,12 +429,14 @@ typedef struct XHCIInterrupter {
     uint32_t erdp_low;
     uint32_t erdp_high;
 
-    bool msix_used, er_pcs, er_full;
+    bool msix_used, er_pcs;
 
     dma_addr_t er_start;
     uint32_t er_size;
     unsigned int er_ep_idx;
 
+    /* kept for live migration compat only */
+    bool er_full_unused;
     XHCIEvent ev_buffer[EV_QUEUE];
     unsigned int ev_buffer_put;
     unsigned int ev_buffer_get;
@@ -486,9 +486,13 @@ struct XHCIState {
     XHCIInterrupter intr[MAXINTRS];
 
     XHCIRing cmd_ring;
+
+    bool nec_quirks;
 };
 
-#define TYPE_XHCI "nec-usb-xhci"
+#define TYPE_XHCI "base-xhci"
+#define TYPE_NEC_XHCI "nec-usb-xhci"
+#define TYPE_QEMU_XHCI "qemu-xhci"
 
 #define XHCI(obj) \
     OBJECT_CHECK(XHCIState, (obj), TYPE_XHCI)
@@ -549,7 +553,6 @@ static const char *TRBType_names[] = {
     [ER_HOST_CONTROLLER]               = "ER_HOST_CONTROLLER",
     [ER_DEVICE_NOTIFICATION]           = "ER_DEVICE_NOTIFICATION",
     [ER_MFINDEX_WRAP]                  = "ER_MFINDEX_WRAP",
-    [CR_VENDOR_VIA_CHALLENGE_RESPONSE] = "CR_VENDOR_VIA_CHALLENGE_RESPONSE",
     [CR_VENDOR_NEC_FIRMWARE_REVISION]  = "CR_VENDOR_NEC_FIRMWARE_REVISION",
     [CR_VENDOR_NEC_CHALLENGE_RESPONSE] = "CR_VENDOR_NEC_CHALLENGE_RESPONSE",
 };
@@ -826,7 +829,7 @@ static void xhci_intr_raise(XHCIState *xhci, int v)
 
 static inline int xhci_running(XHCIState *xhci)
 {
-    return !(xhci->usbsts & USBSTS_HCH) && !xhci->intr[0].er_full;
+    return !(xhci->usbsts & USBSTS_HCH);
 }
 
 static void xhci_die(XHCIState *xhci)
@@ -865,74 +868,6 @@ static void xhci_write_event(XHCIState *xhci, XHCIEvent *event, int v)
     }
 }
 
-static void xhci_events_update(XHCIState *xhci, int v)
-{
-    XHCIInterrupter *intr = &xhci->intr[v];
-    dma_addr_t erdp;
-    unsigned int dp_idx;
-    bool do_irq = 0;
-
-    if (xhci->usbsts & USBSTS_HCH) {
-        return;
-    }
-
-    erdp = xhci_addr64(intr->erdp_low, intr->erdp_high);
-    if (erdp < intr->er_start ||
-        erdp >= (intr->er_start + TRB_SIZE*intr->er_size)) {
-        DPRINTF("xhci: ERDP out of bounds: "DMA_ADDR_FMT"\n", erdp);
-        DPRINTF("xhci: ER[%d] at "DMA_ADDR_FMT" len %d\n",
-                v, intr->er_start, intr->er_size);
-        xhci_die(xhci);
-        return;
-    }
-    dp_idx = (erdp - intr->er_start) / TRB_SIZE;
-    assert(dp_idx < intr->er_size);
-
-    /* NEC didn't read section 4.9.4 of the spec (v1.0 p139 top Note) and thus
-     * deadlocks when the ER is full. Hack it by holding off events until
-     * the driver decides to free at least half of the ring */
-    if (intr->er_full) {
-        int er_free = dp_idx - intr->er_ep_idx;
-        if (er_free <= 0) {
-            er_free += intr->er_size;
-        }
-        if (er_free < (intr->er_size/2)) {
-            DPRINTF("xhci_events_update(): event ring still "
-                    "more than half full (hack)\n");
-            return;
-        }
-    }
-
-    while (intr->ev_buffer_put != intr->ev_buffer_get) {
-        assert(intr->er_full);
-        if (((intr->er_ep_idx+1) % intr->er_size) == dp_idx) {
-            DPRINTF("xhci_events_update(): event ring full again\n");
-#ifndef ER_FULL_HACK
-            XHCIEvent full = {ER_HOST_CONTROLLER, CC_EVENT_RING_FULL_ERROR};
-            xhci_write_event(xhci, &full, v);
-#endif
-            do_irq = 1;
-            break;
-        }
-        XHCIEvent *event = &intr->ev_buffer[intr->ev_buffer_get];
-        xhci_write_event(xhci, event, v);
-        intr->ev_buffer_get++;
-        do_irq = 1;
-        if (intr->ev_buffer_get == EV_QUEUE) {
-            intr->ev_buffer_get = 0;
-        }
-    }
-
-    if (do_irq) {
-        xhci_intr_raise(xhci, v);
-    }
-
-    if (intr->er_full && intr->ev_buffer_put == intr->ev_buffer_get) {
-        DPRINTF("xhci_events_update(): event ring no longer full\n");
-        intr->er_full = 0;
-    }
-}
-
 static void xhci_event(XHCIState *xhci, XHCIEvent *event, int v)
 {
     XHCIInterrupter *intr;
@@ -945,19 +880,6 @@ static void xhci_event(XHCIState *xhci, XHCIEvent *event, int v)
     }
     intr = &xhci->intr[v];
 
-    if (intr->er_full) {
-        DPRINTF("xhci_event(): ER full, queueing\n");
-        if (((intr->ev_buffer_put+1) % EV_QUEUE) == intr->ev_buffer_get) {
-            DPRINTF("xhci: event queue full, dropping event!\n");
-            return;
-        }
-        intr->ev_buffer[intr->ev_buffer_put++] = *event;
-        if (intr->ev_buffer_put == EV_QUEUE) {
-            intr->ev_buffer_put = 0;
-        }
-        return;
-    }
-
     erdp = xhci_addr64(intr->erdp_low, intr->erdp_high);
     if (erdp < intr->er_start ||
         erdp >= (intr->er_start + TRB_SIZE*intr->er_size)) {
@@ -971,21 +893,12 @@ static void xhci_event(XHCIState *xhci, XHCIEvent *event, int v)
     dp_idx = (erdp - intr->er_start) / TRB_SIZE;
     assert(dp_idx < intr->er_size);
 
-    if ((intr->er_ep_idx+1) % intr->er_size == dp_idx) {
-        DPRINTF("xhci_event(): ER full, queueing\n");
-#ifndef ER_FULL_HACK
+    if ((intr->er_ep_idx + 2) % intr->er_size == dp_idx) {
+        DPRINTF("xhci: ER %d full, send ring full error\n", v);
         XHCIEvent full = {ER_HOST_CONTROLLER, CC_EVENT_RING_FULL_ERROR};
-        xhci_write_event(xhci, &full);
-#endif
-        intr->er_full = 1;
-        if (((intr->ev_buffer_put+1) % EV_QUEUE) == intr->ev_buffer_get) {
-            DPRINTF("xhci: event queue full, dropping event!\n");
-            return;
-        }
-        intr->ev_buffer[intr->ev_buffer_put++] = *event;
-        if (intr->ev_buffer_put == EV_QUEUE) {
-            intr->ev_buffer_put = 0;
-        }
+        xhci_write_event(xhci, &full, v);
+    } else if ((intr->er_ep_idx + 1) % intr->er_size == dp_idx) {
+        DPRINTF("xhci: ER %d full, drop event\n", v);
     } else {
         xhci_write_event(xhci, event, v);
     }
@@ -1032,6 +945,7 @@ static TRBType xhci_ring_fetch(XHCIState *xhci, XHCIRing *ring, XHCITRB *trb,
             return type;
         } else {
             if (++link_cnt > TRB_LINK_LIMIT) {
+                trace_usb_xhci_enforced_limit("trb-link");
                 return 0;
             }
             ring->dequeue = xhci_mask64(trb->parameter);
@@ -1124,7 +1038,6 @@ static void xhci_er_reset(XHCIState *xhci, int v)
 
     intr->er_ep_idx = 0;
     intr->er_pcs = 1;
-    intr->er_full = 0;
 
     DPRINTF("xhci: event ring[%d]:" DMA_ADDR_FMT " [%d]\n",
             v, intr->er_start, intr->er_size);
@@ -2150,6 +2063,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
     XHCIRing *ring;
     USBEndpoint *ep = NULL;
     uint64_t mfindex;
+    unsigned int count = 0;
     int length;
     int i;
 
@@ -2262,6 +2176,10 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
             epctx->retry = xfer;
             break;
         }
+        if (count++ > TRANSFER_LIMIT) {
+            trace_usb_xhci_enforced_limit("transfers");
+            break;
+        }
     }
     epctx->kick_active--;
 
@@ -2702,39 +2620,13 @@ static uint32_t xhci_nec_challenge(uint32_t hi, uint32_t lo)
     return ~val;
 }
 
-static void xhci_via_challenge(XHCIState *xhci, uint64_t addr)
-{
-    PCIDevice *pci_dev = PCI_DEVICE(xhci);
-    uint32_t buf[8];
-    uint32_t obuf[8];
-    dma_addr_t paddr = xhci_mask64(addr);
-
-    pci_dma_read(pci_dev, paddr, &buf, 32);
-
-    memcpy(obuf, buf, sizeof(obuf));
-
-    if ((buf[0] & 0xff) == 2) {
-        obuf[0] = 0x49932000 + 0x54dc200 * buf[2] + 0x7429b578 * buf[3];
-        obuf[0] |=  (buf[2] * buf[3]) & 0xff;
-        obuf[1] = 0x0132bb37 + 0xe89 * buf[2] + 0xf09 * buf[3];
-        obuf[2] = 0x0066c2e9 + 0x2091 * buf[2] + 0x19bd * buf[3];
-        obuf[3] = 0xd5281342 + 0x2cc9691 * buf[2] + 0x2367662 * buf[3];
-        obuf[4] = 0x0123c75c + 0x1595 * buf[2] + 0x19ec * buf[3];
-        obuf[5] = 0x00f695de + 0x26fd * buf[2] + 0x3e9 * buf[3];
-        obuf[6] = obuf[2] ^ obuf[3] ^ 0x29472956;
-        obuf[7] = obuf[2] ^ obuf[3] ^ 0x65866593;
-    }
-
-    pci_dma_write(pci_dev, paddr, &obuf, 32);
-}
-
 static void xhci_process_commands(XHCIState *xhci)
 {
     XHCITRB trb;
     TRBType type;
     XHCIEvent event = {ER_COMMAND_COMPLETE, CC_SUCCESS};
     dma_addr_t addr;
-    unsigned int i, slotid = 0;
+    unsigned int i, slotid = 0, count = 0;
 
     DPRINTF("xhci_process_commands()\n");
     if (!xhci_running(xhci)) {
@@ -2823,24 +2715,27 @@ static void xhci_process_commands(XHCIState *xhci)
         case CR_GET_PORT_BANDWIDTH:
             event.ccode = xhci_get_port_bandwidth(xhci, trb.parameter);
             break;
-        case CR_VENDOR_VIA_CHALLENGE_RESPONSE:
-            xhci_via_challenge(xhci, trb.parameter);
-            break;
         case CR_VENDOR_NEC_FIRMWARE_REVISION:
-            event.type = 48; /* NEC reply */
-            event.length = 0x3025;
+            if (xhci->nec_quirks) {
+                event.type = 48; /* NEC reply */
+                event.length = 0x3025;
+            } else {
+                event.ccode = CC_TRB_ERROR;
+            }
             break;
         case CR_VENDOR_NEC_CHALLENGE_RESPONSE:
-        {
-            uint32_t chi = trb.parameter >> 32;
-            uint32_t clo = trb.parameter;
-            uint32_t val = xhci_nec_challenge(chi, clo);
-            event.length = val & 0xFFFF;
-            event.epid = val >> 16;
-            slotid = val >> 24;
-            event.type = 48; /* NEC reply */
-        }
-        break;
+            if (xhci->nec_quirks) {
+                uint32_t chi = trb.parameter >> 32;
+                uint32_t clo = trb.parameter;
+                uint32_t val = xhci_nec_challenge(chi, clo);
+                event.length = val & 0xFFFF;
+                event.epid = val >> 16;
+                slotid = val >> 24;
+                event.type = 48; /* NEC reply */
+            } else {
+                event.ccode = CC_TRB_ERROR;
+            }
+            break;
         default:
             trace_usb_xhci_unimplemented("command", type);
             event.ccode = CC_TRB_ERROR;
@@ -2848,6 +2743,11 @@ static void xhci_process_commands(XHCIState *xhci)
         }
         event.slotid = slotid;
         xhci_event(xhci, &event, 0);
+
+        if (count++ > COMMAND_LIMIT) {
+            trace_usb_xhci_enforced_limit("commands");
+            return;
+        }
     }
 }
 
@@ -2978,7 +2878,6 @@ static void xhci_reset(DeviceState *dev)
 
         xhci->intr[i].er_ep_idx = 0;
         xhci->intr[i].er_pcs = 1;
-        xhci->intr[i].er_full = 0;
         xhci->intr[i].ev_buffer_put = 0;
         xhci->intr[i].ev_buffer_get = 0;
     }
@@ -3343,9 +3242,12 @@ static void xhci_runtime_write(void *ptr, hwaddr reg,
         intr->erstsz = val & 0xffff;
         break;
     case 0x10: /* ERSTBA low */
-        /* XXX NEC driver bug: it doesn't align this to 64 bytes
-        intr->erstba_low = val & 0xffffffc0; */
-        intr->erstba_low = val & 0xfffffff0;
+        if (xhci->nec_quirks) {
+            /* NEC driver bug: it doesn't align this to 64 bytes */
+            intr->erstba_low = val & 0xfffffff0;
+        } else {
+            intr->erstba_low = val & 0xffffffc0;
+        }
         break;
     case 0x14: /* ERSTBA high */
         intr->erstba_high = val;
@@ -3368,7 +3270,6 @@ static void xhci_runtime_write(void *ptr, hwaddr reg,
         break;
     case 0x1c: /* ERDP high */
         intr->erdp_high = val;
-        xhci_events_update(xhci, v);
         break;
     default:
         trace_usb_xhci_unimplemented("oper write", reg);
@@ -3641,6 +3542,9 @@ static void usb_xhci_realize(struct PCIDevice *dev, Error **errp)
     dev->config[PCI_CACHE_LINE_SIZE] = 0x10;
     dev->config[0x60] = 0x30; /* release number */
 
+    if (strcmp(object_get_typename(OBJECT(dev)), TYPE_NEC_XHCI) == 0) {
+        xhci->nec_quirks = true;
+    }
     if (xhci->numintrs > MAXINTRS) {
         xhci->numintrs = MAXINTRS;
     }
@@ -3866,8 +3770,7 @@ static const VMStateDescription vmstate_xhci_event = {
 
 static bool xhci_er_full(void *opaque, int version_id)
 {
-    struct XHCIInterrupter *intr = opaque;
-    return intr->er_full;
+    return false;
 }
 
 static const VMStateDescription vmstate_xhci_intr = {
@@ -3891,7 +3794,7 @@ static const VMStateDescription vmstate_xhci_intr = {
         VMSTATE_UINT32(er_ep_idx,     XHCIInterrupter),
 
         /* event queue (used if ring is full) */
-        VMSTATE_BOOL(er_full,         XHCIInterrupter),
+        VMSTATE_BOOL(er_full_unused,  XHCIInterrupter),
         VMSTATE_UINT32_TEST(ev_buffer_put, XHCIInterrupter, xhci_er_full),
         VMSTATE_UINT32_TEST(ev_buffer_get, XHCIInterrupter, xhci_er_full),
         VMSTATE_STRUCT_ARRAY_TEST(ev_buffer, XHCIInterrupter, EV_QUEUE,
@@ -3963,10 +3866,7 @@ static void xhci_class_init(ObjectClass *klass, void *data)
     set_bit(DEVICE_CATEGORY_USB, dc->categories);
     k->realize      = usb_xhci_realize;
     k->exit         = usb_xhci_exit;
-    k->vendor_id    = PCI_VENDOR_ID_NEC;
-    k->device_id    = PCI_DEVICE_ID_NEC_UPD720200;
     k->class_id     = PCI_CLASS_SERIAL_USB;
-    k->revision     = 0x03;
     k->is_express   = 1;
 }
 
@@ -3975,11 +3875,44 @@ static const TypeInfo xhci_info = {
     .parent        = TYPE_PCI_DEVICE,
     .instance_size = sizeof(XHCIState),
     .class_init    = xhci_class_init,
+    .abstract      = true,
+};
+
+static void nec_xhci_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->vendor_id    = PCI_VENDOR_ID_NEC;
+    k->device_id    = PCI_DEVICE_ID_NEC_UPD720200;
+    k->revision     = 0x03;
+}
+
+static const TypeInfo nec_xhci_info = {
+    .name          = TYPE_NEC_XHCI,
+    .parent        = TYPE_XHCI,
+    .class_init    = nec_xhci_class_init,
+};
+
+static void qemu_xhci_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->vendor_id    = PCI_VENDOR_ID_REDHAT;
+    k->device_id    = PCI_DEVICE_ID_REDHAT_XHCI;
+    k->revision     = 0x01;
+}
+
+static const TypeInfo qemu_xhci_info = {
+    .name          = TYPE_QEMU_XHCI,
+    .parent        = TYPE_XHCI,
+    .class_init    = qemu_xhci_class_init,
 };
 
 static void xhci_register_types(void)
 {
     type_register_static(&xhci_info);
+    type_register_static(&nec_xhci_info);
+    type_register_static(&qemu_xhci_info);
 }
 
 type_init(xhci_register_types)
diff --git a/hw/usb/trace-events b/hw/usb/trace-events
index fdd1d29..0c323d4 100644
--- a/hw/usb/trace-events
+++ b/hw/usb/trace-events
@@ -174,6 +174,7 @@ usb_xhci_xfer_retry(void *xfer) "%p"
 usb_xhci_xfer_success(void *xfer, uint32_t bytes) "%p: len %d"
 usb_xhci_xfer_error(void *xfer, uint32_t ret) "%p: ret %d"
 usb_xhci_unimplemented(const char *item, int nr) "%s (0x%x)"
+usb_xhci_enforced_limit(const char *item) "%s"
 
 # hw/usb/desc.c
 usb_desc_device(int addr, int len, int ret) "dev %d query device, len %d, ret %d"
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index cbc1fdf..05ef14b 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -97,6 +97,7 @@
 #define PCI_DEVICE_ID_REDHAT_BRIDGE_SEAT 0x000a
 #define PCI_DEVICE_ID_REDHAT_PXB_PCIE    0x000b
 #define PCI_DEVICE_ID_REDHAT_PCIE_RP     0x000c
+#define PCI_DEVICE_ID_REDHAT_XHCI        0x000d
 #define PCI_DEVICE_ID_REDHAT_QXL         0x0100
 
 #define FMT_PCIBUS                      PRIx64