[RFC QEMU PATCH v6 1/1] xen/pci: get gsi from irq for passthrough devices

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

In PVH dom0, it uses the linux local interrupt mechanism,
when it allocs irq for a gsi, it is dynamic, and follow
the principle of applying first, distributing first. And
the irq number is alloced from small to large, but the
applying gsi number is not, may gsi 38 comes before gsi
28, that causes the irq number is not equal with the gsi
number. And when passthrough a device, qemu wants to use
gsi to map pirq, xen_pt_realize->xc_physdev_map_pirq, but
the gsi number is got from file
/sys/bus/pci/devices/<sbdf>/irq in current code, so it
will fail when mapping.

Translate irq to gsi by using new function supported by
Xen tools.

Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
 hw/xen/xen-host-pci-device.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c
index 8c6e9a1716a2..5e9aa9679e3e 100644
--- a/hw/xen/xen-host-pci-device.c
+++ b/hw/xen/xen-host-pci-device.c
@@ -10,6 +10,7 @@
 #include "qapi/error.h"
 #include "qemu/cutils.h"
 #include "xen-host-pci-device.h"
+#include "hw/xen/xen_native.h"
 
 #define XEN_HOST_PCI_MAX_EXT_CAP \
     ((PCIE_CONFIG_SPACE_SIZE - PCI_CONFIG_SPACE_SIZE) / (PCI_CAP_SIZEOF + 4))
@@ -368,7 +369,11 @@ void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t 
domain,
     if (*errp) {
         goto error;
     }
-    d->irq = v;
+    d->irq = xc_physdev_gsi_from_irq(xen_xc, v);
+    /* if fail to get gsi, fallback to irq */
+    if (d->irq == -1) {
+        d->irq = v;
+    }
 
     xen_host_pci_get_hex_value(d, "class", &v, errp);
     if (*errp) {
-- 
2.34.1