Re: [PATCH] KVM: VMX: Avoid writing HOST_CR0 every entry

On Mon, May 03, 2010 at 05:18:54PM +0300, Avi Kivity wrote: cr0.ts may change between entries, so we copy cr0 to HOST_CR0 before each entry. That is slow, so instead, set HOST_CR0 to have TS set unconditionally (which is a safe value), and issue a clts() just before exiting vcpu context if

[PATCH] KVM: VMX: Avoid writing HOST_CR0 every entry

cr0.ts may change between entries, so we copy cr0 to HOST_CR0 before each entry. That is slow, so instead, set HOST_CR0 to have TS set unconditionally (which is a safe value), and issue a clts() just before exiting vcpu context if the task indeed owns the fpu. Saves ~50 cycles/exit.