Dear all, I have a PCIe device driver that I have been using on various Linux distributions and Kernel versions (2.6.x - 3.x.y) successfully all along. I recently set up a Xen environment with Linux Mint 12 and Xen Hypervisor 4.1. When I boot to Linux Mint, my driver still load (via insmod manually) successfully at Dom0 without any issue. I can do reads and write to the hardware device. But once booted to Xen, the driver failed to complete the driver load (via insmod manually) at Dom 0 and the console just hangs. From my debug messages, it appears it hangs because the driver doesn''t receive any interrupt after a command is sent to the hardware device by writing a parameter to the mapped register. Once that register is written, the device is expected to DMA the command from the buffer allocated by the driver. The things that I can only think of that might have caused the problem are 1) IRQ mapping issue, or 2) DMA mapping issue, which I am not sure. What the driver does: Set up a command buffer: Buf_t *buf = kmalloc(BUF_SIZE*sizeof(buf_t), GFP_KERNEL); unsigned long buf_addr = __pa(buf); unsigned int buf_addr_low = (unsigned int)buf_addr; Tell device about the buffer: iowrite32(buf_addr_low, dev->pci_reg_map + BUF_ADR__LOW); Set up IRQ: if (pci_find_capability(dev, PCI_CAP_ID_MSI) && (!pci_enable_msi(dev))) { if (request_irq(dev->irq, func_msi_interrupt, IRQF_SHARED, DRIVER_NAME, my_dev)) { return -ENODEV; } my_dev->intr_mode = INTERRUPT_MSI; } Ask device to fetch command from buffer (Expect interrupt after this after device fetched the command from buf. But interrupt did not happen.): iowrite32(buf_offset, dev->pci_reg_map + FETCH_CMD_REG); From dmesg, it looks like IRQ initialization is complete. [ 241.743769] My_driver initialization [ 241.743787] xen: registering gsi 16 triggering 0 polarity 1 [ 241.743793] xen_map_pirq_gsi: returning irq 16 for gsi 16 [ 241.743795] xen: --> pirq=16 -> irq=16 (gsi=16) [ 241.743801] Already setup the GSI :16 [ 241.743805] my-driver 0000:02:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [ 241.743815] my-driver 0000:02:00.0: setting latency timer to 64 /proc/interrupts: CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7 ...... ...... 339: 0 0 0 0 0 0 0 0 xen-pirq-msi my-driver ...... ...... Any idea what might cause the problem? Is there anything we have to be enable/disable, use different functions, or do differently in drivers written for Xen Dom0 environment regarding the following? 1) Allocating a DMA buffer in driver to allow the device to DMA stuffs. 2) Requesting MSI irq. Please advise! Thanks a lot in advance!! Kenneth _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users