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Commit 4051b188 authored by Joerg Roedel's avatar Joerg Roedel Committed by Avi Kivity
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KVM: X86: Implement call-back to propagate virtual_tsc_khz 



This patch implements a call-back into the architecture code
to allow the propagation of changes to the virtual tsc_khz
of the vcpu.
On SVM it updates the tsc_ratio variable, on VMX it does
nothing.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 8f6055cb

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -606,6 +606,7 @@ struct kvm_x86_ops { 


	bool (*has_wbinvd_exit)(void);



	void (*set_tsc_khz)(struct kvm_vcpu *vcpu, u32 user_tsc_khz);

	void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);



	void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);

arch/x86/kvm/svm.c

+33 −0
Original line number Diff line number Diff line
@@ -885,6 +885,38 @@ static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc) 
	return _tsc;

}



static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)

{

	struct vcpu_svm *svm = to_svm(vcpu);

	u64 ratio;

	u64 khz;



	/* TSC scaling supported? */

	if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR))

		return;



	/* TSC-Scaling disabled or guest TSC same frequency as host TSC? */

	if (user_tsc_khz == 0) {

		vcpu->arch.virtual_tsc_khz = 0;

		svm->tsc_ratio = TSC_RATIO_DEFAULT;

		return;

	}



	khz = user_tsc_khz;



	/* TSC scaling required  - calculate ratio */

	ratio = khz << 32;

	do_div(ratio, tsc_khz);



	if (ratio == 0 || ratio & TSC_RATIO_RSVD) {

		WARN_ONCE(1, "Invalid TSC ratio - virtual-tsc-khz=%u\n",

				user_tsc_khz);

		return;

	}

	vcpu->arch.virtual_tsc_khz = user_tsc_khz;

	svm->tsc_ratio             = ratio;

}



static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)

{

	struct vcpu_svm *svm = to_svm(vcpu);
@@ -4159,6 +4191,7 @@ static struct kvm_x86_ops svm_x86_ops = { 


	.has_wbinvd_exit = svm_has_wbinvd_exit,



	.set_tsc_khz = svm_set_tsc_khz,

	.write_tsc_offset = svm_write_tsc_offset,

	.adjust_tsc_offset = svm_adjust_tsc_offset,

arch/x86/kvm/vmx.c

+11 −0
Original line number Diff line number Diff line
@@ -1160,6 +1160,16 @@ static u64 guest_read_tsc(void) 
	return host_tsc + tsc_offset;

}



/*

 * Empty call-back. Needs to be implemented when VMX enables the SET_TSC_KHZ

 * ioctl. In this case the call-back should update internal vmx state to make

 * the changes effective.

 */

static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)

{

	/* Nothing to do here */

}



/*

 * writes 'offset' into guest's timestamp counter offset register

 */
@@ -4497,6 +4507,7 @@ static struct kvm_x86_ops vmx_x86_ops = { 


	.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,



	.set_tsc_khz = vmx_set_tsc_khz,

	.write_tsc_offset = vmx_write_tsc_offset,

	.adjust_tsc_offset = vmx_adjust_tsc_offset,