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[Xen-devel] [PATCH] [IOEMU] Fix wrong INTx for pass-through device

To: Simon Horman <horms@xxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH] [IOEMU] Fix wrong INTx for pass-through device
From: "Zhai, Edwin" <edwin.zhai@xxxxxxxxx>
Date: Mon, 28 Dec 2009 15:04:59 +0800
Cc: Xen Developers <xen-devel@xxxxxxxxxxxxxxxxxxx>, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>, "Zhai, Edwin" <edwin.zhai@xxxxxxxxx>
Delivery-date: Sun, 27 Dec 2009 23:07:53 -0800
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For the pass-through device's INTx emulation, we follow the policy: if virtual function 0, use INTA#, otherwise use hardware value. However, this policy only apply when bind_pt_pci_irq to xen, and always use physical value when exporting to guest. This discrepancy cause different INTx, thus different GSI in xen and guest, so that interrupts never got injected to guest. E.g. when assigning a USB controller with non-zero function(00:1d.2) to guest as 00:4.0, xen will see INTA#, while guest see INTC#.

This simple patch can fix it. Could you pls. review it?


best rgds,

Signed-Off-By: Zhai Edwin <edwin.zhai@xxxxxxxxx>

diff --git a/hw/pass-through.c b/hw/pass-through.c
index e7bd386..a08c0bf 100644
--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -2710,7 +2710,8 @@ static uint32_t pt_status_reg_init(struct pt_dev *ptdev,
 static uint32_t pt_irqpin_reg_init(struct pt_dev *ptdev,
         struct pt_reg_info_tbl *reg, uint32_t real_offset)
-    return ptdev->dev.config[real_offset];
+    /* Translate xen INTx value to hw */
+    return pci_intx(ptdev) + 1;
 /* initialize BAR */
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