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This is the host side counterpart to the frontend driver in drivers/pci/xen-pcifront.c. The PV protocol is also implemented by frontend drivers in other OSes too, such as the BSDs. The PV protocol is rather simple. There is page shared with the guest, which has the 'struct xen_pci_sharedinfo' embossed in it. The backend has a thread that is kicked every-time the structure is changed and based on the operation field it performs specific tasks: XEN_PCI_OP_conf_[read|write]: Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c) Based on which field is probed, we either enable/disable the PCI device, change power state, read VPD, etc. The major goal of this call is to provide a Physical IRQ (PIRQ) to the guest. The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ is tied in to the IO-APIC, or is a vector. For GSI type interrupts, the PIRQ==GSI holds. For MSI/MSI-X the PIRQ value != Linux IRQ number (thought PIRQ==vector). Please note, that with Xen, all interrupts (except those level shared ones) are injected directly to the guest - there is no host interaction. XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c) Enables/disables the MSI/MSI-X capability of the device. These operations setup the MSI/MSI-X vectors for the guest and pass them to the frontend. When the device is activated, the interrupts are directly injected in the guest without involving the host. XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure, perform the appropriate AER commands on the guest. Right now that is a cop-out - we just kill the guest. Besides implementing those commands, it can also - hide a PCI device from the host. When booting up, the user can specify xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the device. The driver was lifted from linux-2.6.18.hg tree and fixed up so that it could compile under v3.0. Per suggestion from Jesse Barnes moved the driver to drivers/xen/xen-pciback. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
41 lines
906 B
C
41 lines
906 B
C
/*
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* PCI Backend - Configuration space overlay for Vital Product Data
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*
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* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
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*/
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#include <linux/pci.h>
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#include "conf_space.h"
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#include "conf_space_capability.h"
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static int vpd_address_write(struct pci_dev *dev, int offset, u16 value,
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void *data)
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{
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/* Disallow writes to the vital product data */
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if (value & PCI_VPD_ADDR_F)
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return PCIBIOS_SET_FAILED;
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else
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return pci_write_config_word(dev, offset, value);
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}
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static const struct config_field caplist_vpd[] = {
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{
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.offset = PCI_VPD_ADDR,
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.size = 2,
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.u.w.read = pciback_read_config_word,
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.u.w.write = vpd_address_write,
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},
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{
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.offset = PCI_VPD_DATA,
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.size = 4,
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.u.dw.read = pciback_read_config_dword,
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.u.dw.write = NULL,
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},
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{}
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};
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struct pciback_config_capability pciback_config_capability_vpd = {
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.capability = PCI_CAP_ID_VPD,
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.fields = caplist_vpd,
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};
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