reserve

Synopsis:

reserve options

Options:

intr guest_intr

Prevent the qvm process from allocating a guest interrupt with the number specified by guest_intr.

loc location_spec [,length]

Prevent the qvm process from allocating the location specified by location_spec.

If the reserved location is a PCI location (pci:), you must use the BDF specification form:

pci:bus_number:device_number[.function_number]

and not specify length.

If the reserved location is a memory location (mem:), you must specify length.

For more information about locations, see “Guest resource types” in the “Configuration” chapter.

Description:

The reserve option reserves locations in guest-physical memory and/or guest interrupts to prevent the qvm process from allocating them to any component or device.

If a guest OS expects that specific locations will hold some predetermined artifact (such as a table), or that specific interrupts will be used for some predetermined purposes, you should use the reserve option to ensure that when the qvm process assembles the VM for the guest it doesn't inadvertently allocate these locations and interrupts, and leaves them for you to allocate as your guest requires.

Any loc or intr option that follows a reserve option specifies, respectively, a reserved location in guest-physical memory, or a guest interrupt number.

The following examples illustrate how the reserve option can be used to reserve different types of resources:

• Guest interrupt 39:

  reserve intr 39

• PCI device 1 on bus 0:

  reserve loc pci:0:1

• An x86 I/O region of eight bytes at 0xcf:

  reserve loc io 0xcf,0x8

• A memory region of eight bytes at 0x1000:

  reserve loc 0x1000,0x8