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. Signed-off-by: Avi Kivity <avi@xxxxxxxxxx> --- arch/x86/kvm/vmx.c | 9 +++------ 1 files changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 875b785..9cfdc0e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -753,6 +753,8 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); } #endif + if (current_thread_info()->status & TS_USEDFPU) + clts(); } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -2441,7 +2443,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, !!bypass_guest_pf); vmcs_write32(CR3_TARGET_COUNT, 0); /* 22.2.1 */ - vmcs_writel(HOST_CR0, read_cr0()); /* 22.2.3 */ + vmcs_writel(HOST_CR0, read_cr0() | X86_CR0_TS); /* 22.2.3 */ vmcs_writel(HOST_CR4, read_cr4()); /* 22.2.3, 22.2.5 */ vmcs_writel(HOST_CR3, read_cr3()); /* 22.2.3 FIXME: shadow tables */ @@ -3794,11 +3796,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) vmx_set_interrupt_shadow(vcpu, 0); - /* - * Loading guest fpu may have cleared host cr0.ts - */ - vmcs_writel(HOST_CR0, read_cr0()); - asm( /* Store host registers */ "push %%"R"dx; push %%"R"bp;" -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
