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Commit 1e993611 authored by Joerg Roedel's avatar Joerg Roedel Committed by Avi Kivity
Browse files

KVM: X86: Let kvm-clock report the right tsc frequency 



This patch changes the kvm_guest_time_update function to use
TSC frequency the guest actually has for updating its clock.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent fbc0db76

arch/x86/include/asm/kvm_host.h

+3 −3
Original line number Diff line number Diff line
@@ -396,7 +396,10 @@ struct kvm_vcpu_arch { 
	u64 last_kernel_ns;

	u64 last_tsc_nsec;

	u64 last_tsc_write;

	u32 virtual_tsc_khz;

	bool tsc_catchup;

	u32  tsc_catchup_mult;

	s8   tsc_catchup_shift;



	bool nmi_pending;

	bool nmi_injected;
@@ -466,9 +469,6 @@ struct kvm_arch { 
	u64 last_tsc_nsec;

	u64 last_tsc_offset;

	u64 last_tsc_write;

	u32 virtual_tsc_khz;

	u32 virtual_tsc_mult;

	s8 virtual_tsc_shift;



	struct kvm_xen_hvm_config xen_hvm_config;

arch/x86/kvm/x86.c

+15 −10
Original line number Diff line number Diff line
@@ -969,6 +969,14 @@ static inline int kvm_tsc_changes_freq(void) 
	return ret;

}



static u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu)

{

	if (vcpu->arch.virtual_tsc_khz)

		return vcpu->arch.virtual_tsc_khz;

	else

		return __this_cpu_read(cpu_tsc_khz);

}



static inline u64 nsec_to_cycles(u64 nsec)

{

	u64 ret;
@@ -982,20 +990,19 @@ static inline u64 nsec_to_cycles(u64 nsec) 
	return ret;

}



static void kvm_arch_set_tsc_khz(struct kvm *kvm, u32 this_tsc_khz)

static void kvm_init_tsc_catchup(struct kvm_vcpu *vcpu, u32 this_tsc_khz)

{

	/* Compute a scale to convert nanoseconds in TSC cycles */

	kvm_get_time_scale(this_tsc_khz, NSEC_PER_SEC / 1000,

			   &kvm->arch.virtual_tsc_shift,

			   &kvm->arch.virtual_tsc_mult);

	kvm->arch.virtual_tsc_khz = this_tsc_khz;

			   &vcpu->arch.tsc_catchup_shift,

			   &vcpu->arch.tsc_catchup_mult);

}



static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)

{

	u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.last_tsc_nsec,

				      vcpu->kvm->arch.virtual_tsc_mult,

				      vcpu->kvm->arch.virtual_tsc_shift);

				      vcpu->arch.tsc_catchup_mult,

				      vcpu->arch.tsc_catchup_shift);

	tsc += vcpu->arch.last_tsc_write;

	return tsc;

}
@@ -1062,8 +1069,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) 
	local_irq_save(flags);

	kvm_get_msr(v, MSR_IA32_TSC, &tsc_timestamp);

	kernel_ns = get_kernel_ns();

	this_tsc_khz = __this_cpu_read(cpu_tsc_khz);



	this_tsc_khz = vcpu_tsc_khz(v);

	if (unlikely(this_tsc_khz == 0)) {

		local_irq_restore(flags);

		kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
@@ -6060,8 +6066,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) 
	}

	vcpu->arch.pio_data = page_address(page);



	if (!kvm->arch.virtual_tsc_khz)

		kvm_arch_set_tsc_khz(kvm, max_tsc_khz);

	kvm_init_tsc_catchup(vcpu, max_tsc_khz);



	r = kvm_mmu_create(vcpu);

	if (r < 0)