What:		/sys/devices/pci0000:00/*/QEMU0001:00/capability for MMIO
		/sys/bus/pci/drivers/pvpanic-pci/0000:00:0*.0/capability for PCI
Date:		Jan 2021
Contact:	zhenwei pi <pizhenwei@bytedance.com>
Description:
		Read-only attribute. Capabilities of pvpanic device which
		are supported by QEMU.

		Format: %x.

		Detailed bit definition refers to section <Bit Definition>
		from pvpanic device specification:
		https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/specs/pvpanic.txt

What:		/sys/devices/pci0000:00/*/QEMU0001:00/events
		/sys/bus/pci/drivers/pvpanic-pci/0000:00:0*.0/events for PCI
Date:		Jan 2021
Contact:	zhenwei pi <pizhenwei@bytedance.com>
Description:
		RW attribute. Set/get which features in-use. This attribute
		is used to enable/disable feature(s) of pvpanic device.
		Notice that this value should be a subset of capability.

		Format: %x.

		Also refer to pvpanic device specification.
