[ Thanks to Boris
Derzhavets for this link. ]
“KVM as a “full virtualization” is a nice feature
because it allows you to run any operating system virtualized.
However, it’s relatively slow because the hypervisor has to emulate
actual physical devices such as RTL8139 network cards and the most
recent SeaBios emulates IDE interface.This fragment from KVM guest
dmesg log is fair enough :-[ 0.129740] ata_piix 0000:00:01.1: version 2.13
[ 0.129802] ata_piix 0000:00:01.1: setting latency timer to 64
[ 0.129954] scsi0 : ata_piix
[ 0.130522] scsi1 : ata_piix
[ 0.130552] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc000
irq 14
[ 0.130554] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc008
irq 15“Virtio is a Linux standard for network and disk device drivers
where just the guest’s device driver “knows” it is running in a
virtual environment, and cooperates with the hypervisor. This
enables guests to get high performance network and disk operations,
and gives most of the performance benefits of
paravirtualization.”