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Commit 2680d6da authored by Owen Hofmann's avatar Owen Hofmann Committed by Paolo Bonzini
Browse files

kvm: x86: Update tsc multiplier on change. 



vmx.c writes the TSC_MULTIPLIER field in vmx_vcpu_load, but only when a
vcpu has migrated physical cpus. Record the last value written and
update in vmx_vcpu_load on any change, otherwise a cpu migration must
occur for TSC frequency scaling to take effect.

Cc: stable@vger.kernel.org
Fixes: ff2c3a18
Signed-off-by: default avatarOwen Hofmann <osh@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 0178fd7d

arch/x86/kvm/vmx.c

+9 −5
Original line number Diff line number Diff line
@@ -596,6 +596,8 @@ struct vcpu_vmx { 
	/* Support for PML */

#define PML_ENTITY_NUM		512

	struct page *pml_pg;



	u64 current_tsc_ratio;

};



enum segment_cache_field {
@@ -2127,14 +2129,16 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
		rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp);

		vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */



		/* Setup TSC multiplier */

		if (cpu_has_vmx_tsc_scaling())

			vmcs_write64(TSC_MULTIPLIER,

				     vcpu->arch.tsc_scaling_ratio);



		vmx->loaded_vmcs->cpu = cpu;

	}



	/* Setup TSC multiplier */

	if (kvm_has_tsc_control &&

	    vmx->current_tsc_ratio != vcpu->arch.tsc_scaling_ratio) {

		vmx->current_tsc_ratio = vcpu->arch.tsc_scaling_ratio;

		vmcs_write64(TSC_MULTIPLIER, vmx->current_tsc_ratio);

	}



	vmx_vcpu_pi_load(vcpu, cpu);

}