This assertion always happens when we sanitize the CXL memory device.
$ echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize

It is incorrect to register an MSIX number beyond the device's capability.

Increase the device's MSIX number to cover the mailbox msix number(9).

Fixes: 43efb0bfad2b ("hw/cxl/mbox: Wire up interrupts for background completion")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Message-Id: <20250115075834.167504-1-lizhijian@fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 1ce979e7269a34d19ea1a65808df014d8b2acbf6)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 52647b4ac7..72d9371347 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -685,7 +685,7 @@ static void ct3_realize(PCIDevice *pci_dev, Error **errp)
     ComponentRegisters *regs = &cxl_cstate->crb;
     MemoryRegion *mr = &regs->component_registers;
     uint8_t *pci_conf = pci_dev->config;
-    unsigned short msix_num = 6;
+    unsigned short msix_num = 10;
     int i, rc;
 
     QTAILQ_INIT(&ct3d->error_list);
-- 
2.39.5