If the device that is to be shared with a guest is a level device and
the IRQ is shared with the initial domain we need to take actions.
Mainly we install a dummy IRQ handler that will ACK on the interrupt
line so as to not have the initial domain disable the interrupt line.
This dummy IRQ handler is not enabled when the device MSI/MSI-X lines
are set, nor for edge interrupts. And also not for level interrupts
that are not shared amongst devices. Lastly, if the user passes
to the guest all of the PCI devices on the shared line the we won't
install the dummy handler either.
There is also SysFS instrumentation to check its state and turn
IRQ ACKing on/off if necessary.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
These changes are for PV guest to use Virtual Function. Because the VF's
vendor, device registers in cfg space are 0xffff, which are invalid and
ignored by PCI device scan. Values in 'struct pci_dev' are fixed up by
SR-IOV code, and using these values will present correct VID and DID to
PV guest kernel.
And command registers in the cfg space are read only 0, which means we
have to emulate MMIO enable bit (VF only uses MMIO resource) so PV
kernel can work properly.
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Checkpatch found some extra warnings and errors. This mega
patch fixes them all in one big swoop. We also spruce
up the pcistub_ids to use DEFINE_PCI_DEVICE_TABLE macro
(suggested by Jan Beulich).
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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>
