The XHCI specification, section 4.17.1 specifies that "If Interrupter
Mapping is not supported, the Interrupter Target field shall be
ignored by the xHC and all Events targeted at Interrupter 0."

QEMU's XHCI device has so far not specially addressed this case,
so we add a check to xhci_event() to redirect to event ring and
interrupt 0 if mapping is disabled.

Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
---
 hw/usb/hcd-xhci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index d85adaca0dc..5fb140c2382 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -644,6 +644,10 @@ static void xhci_event(XHCIState *xhci, XHCIEvent *event, int v)
     dma_addr_t erdp;
     unsigned int dp_idx;
 
+    if (xhci->numintrs == 1) {
+        v = 0;
+    }
+
     if (v >= xhci->numintrs) {
         DPRINTF("intr nr out of range (%d >= %d)\n", v, xhci->numintrs);
         return;
-- 
2.39.5 (Apple Git-154)

Remove the period from the subject.

On 2024/12/09 4:16, Phil Dennis-Jordan wrote:
> The XHCI specification, section 4.17.1 specifies that "If Interrupter
> Mapping is not supported, the Interrupter Target field shall be
> ignored by the xHC and all Events targeted at Interrupter 0."
> 
> QEMU's XHCI device has so far not specially addressed this case,
> so we add a check to xhci_event() to redirect to event ring and
> interrupt 0 if mapping is disabled.
> 
> Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
> ---
>   hw/usb/hcd-xhci.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index d85adaca0dc..5fb140c2382 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -644,6 +644,10 @@ static void xhci_event(XHCIState *xhci, XHCIEvent *event, int v)
>       dma_addr_t erdp;
>       unsigned int dp_idx;
>   
> +    if (xhci->numintrs == 1) {
> +        v = 0;
> +    }
> +
>       if (v >= xhci->numintrs) {
>           DPRINTF("intr nr out of range (%d >= %d)\n", v, xhci->numintrs);
>           return;