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Commit e48672fa authored by Zachary Amsden's avatar Zachary Amsden Committed by Avi Kivity
Browse files

KVM: x86: Unify TSC logic 



Move the TSC control logic from the vendor backends into x86.c
by adding adjust_tsc_offset to x86 ops.  Now all TSC decisions
can be done in one place.

Signed-off-by: default avatarZachary Amsden <zamsden@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 6755bae8

arch/x86/include/asm/kvm_host.h

+3 −2
Original line number Diff line number Diff line
@@ -255,7 +255,6 @@ struct kvm_mmu { 
};



struct kvm_vcpu_arch {

	u64 host_tsc;

	/*

	 * rip and regs accesses must go through

	 * kvm_{register,rip}_{read,write} functions.
@@ -336,9 +335,10 @@ struct kvm_vcpu_arch { 


	gpa_t time;

	struct pvclock_vcpu_time_info hv_clock;

	unsigned int hv_clock_tsc_khz;

	unsigned int hw_tsc_khz;

	unsigned int time_offset;

	struct page *time_page;

	u64 last_host_tsc;



	bool nmi_pending;

	bool nmi_injected;
@@ -520,6 +520,7 @@ struct kvm_x86_ops { 
	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);

	int (*get_lpage_level)(void);

	bool (*rdtscp_supported)(void);

	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment);



	void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry);

arch/x86/kvm/svm.c

+10 −16
Original line number Diff line number Diff line
@@ -715,6 +715,15 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) 
	svm->vmcb->control.tsc_offset = offset + g_tsc_offset;

}



static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)

{

	struct vcpu_svm *svm = to_svm(vcpu);



	svm->vmcb->control.tsc_offset += adjustment;

	if (is_nested(svm))

		svm->nested.hsave->control.tsc_offset += adjustment;

}



static void init_vmcb(struct vcpu_svm *svm)

{

	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -961,20 +970,6 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
	int i;



	if (unlikely(cpu != vcpu->cpu)) {

		u64 delta;



		if (check_tsc_unstable()) {

			/*

			 * Make sure that the guest sees a monotonically

			 * increasing TSC.

			 */

			delta = vcpu->arch.host_tsc - native_read_tsc();

			svm->vmcb->control.tsc_offset += delta;

			if (is_nested(svm))

				svm->nested.hsave->control.tsc_offset += delta;

		}

		vcpu->cpu = cpu;

		kvm_migrate_timers(vcpu);

		svm->asid_generation = 0;

	}
@@ -990,8 +985,6 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu) 
	++vcpu->stat.host_state_reload;

	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)

		wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);



	vcpu->arch.host_tsc = native_read_tsc();

}



static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
@@ -3553,6 +3546,7 @@ static struct kvm_x86_ops svm_x86_ops = { 
	.has_wbinvd_exit = svm_has_wbinvd_exit,



	.write_tsc_offset = svm_write_tsc_offset,

	.adjust_tsc_offset = svm_adjust_tsc_offset,

};



static int __init svm_init(void)

arch/x86/kvm/vmx.c

+8 −14
Original line number Diff line number Diff line
@@ -505,7 +505,6 @@ static void __vcpu_clear(void *arg) 
		vmcs_clear(vmx->vmcs);

	if (per_cpu(current_vmcs, cpu) == vmx->vmcs)

		per_cpu(current_vmcs, cpu) = NULL;

	rdtscll(vmx->vcpu.arch.host_tsc);

	list_del(&vmx->local_vcpus_link);

	vmx->vcpu.cpu = -1;

	vmx->launched = 0;
@@ -881,7 +880,6 @@ static void vmx_load_host_state(struct vcpu_vmx *vmx) 
static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	u64 tsc_this, delta, new_offset;

	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));



	if (!vmm_exclusive)
@@ -898,14 +896,12 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
		struct desc_ptr *gdt = &__get_cpu_var(host_gdt);

		unsigned long sysenter_esp;



		kvm_migrate_timers(vcpu);

		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);

		local_irq_disable();

		list_add(&vmx->local_vcpus_link,

			 &per_cpu(vcpus_on_cpu, cpu));

		local_irq_enable();



		vcpu->cpu = cpu;

		/*

		 * Linux uses per-cpu TSS and GDT, so set these when switching

		 * processors.
@@ -915,16 +911,6 @@ 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 */



		/*

		 * Make sure the time stamp counter is monotonous.

		 */

		rdtscll(tsc_this);

		if (tsc_this < vcpu->arch.host_tsc) {

			delta = vcpu->arch.host_tsc - tsc_this;

			new_offset = vmcs_read64(TSC_OFFSET) + delta;

			vmcs_write64(TSC_OFFSET, new_offset);

		}

	}

}
@@ -1153,6 +1139,12 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) 
	vmcs_write64(TSC_OFFSET, offset);

}



static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)

{

	u64 offset = vmcs_read64(TSC_OFFSET);

	vmcs_write64(TSC_OFFSET, offset + adjustment);

}



/*

 * Reads an msr value (of 'msr_index') into 'pdata'.

 * Returns 0 on success, non-0 otherwise.
@@ -4108,6 +4100,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) 


	cpu = get_cpu();

	vmx_vcpu_load(&vmx->vcpu, cpu);

	vmx->vcpu.cpu = cpu;

	err = vmx_vcpu_setup(vmx);

	vmx_vcpu_put(&vmx->vcpu);

	put_cpu();
@@ -4347,6 +4340,7 @@ static struct kvm_x86_ops vmx_x86_ops = { 
	.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,



	.write_tsc_offset = vmx_write_tsc_offset,

	.adjust_tsc_offset = vmx_adjust_tsc_offset,

};



static int __init vmx_init(void)

arch/x86/kvm/x86.c

+14 −3
Original line number Diff line number Diff line
@@ -973,9 +973,9 @@ static int kvm_write_guest_time(struct kvm_vcpu *v) 
		return 1;

	}



	if (unlikely(vcpu->hv_clock_tsc_khz != this_tsc_khz)) {

	if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {

		kvm_set_time_scale(this_tsc_khz, &vcpu->hv_clock);

		vcpu->hv_clock_tsc_khz = this_tsc_khz;

		vcpu->hw_tsc_khz = this_tsc_khz;

	}



	/* With all the info we got, fill in the values */
@@ -1866,13 +1866,24 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
	}



	kvm_x86_ops->vcpu_load(vcpu, cpu);

	kvm_request_guest_time_update(vcpu);

	if (unlikely(vcpu->cpu != cpu)) {

		/* Make sure TSC doesn't go backwards */

		s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :

				native_read_tsc() - vcpu->arch.last_host_tsc;

		if (tsc_delta < 0)

			mark_tsc_unstable("KVM discovered backwards TSC");

		if (check_tsc_unstable())

			kvm_x86_ops->adjust_tsc_offset(vcpu, -tsc_delta);

		kvm_migrate_timers(vcpu);

		vcpu->cpu = cpu;

	}

}



void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)

{

	kvm_x86_ops->vcpu_put(vcpu);

	kvm_put_guest_fpu(vcpu);

	vcpu->arch.last_host_tsc = native_read_tsc();

}



static int is_efer_nx(void)