Commit f4e1b3c8 authored by Zachary Amsden's avatar Zachary Amsden Committed by Avi Kivity
Browse files

KVM: x86: Convert TSC writes to TSC offset writes 



Change svm / vmx to be the same internally and write TSC offset
instead of bare TSC in helper functions.  Isolated as a single
patch to contain code movement.

Signed-off-by: default avatarZachary Amsden <zamsden@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent ae38436b

arch/x86/kvm/svm.c

+17 −14
Original line number Diff line number Diff line
@@ -701,6 +701,20 @@ static void init_sys_seg(struct vmcb_seg *seg, uint32_t type) 
	seg->base = 0;

}



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

{

	struct vcpu_svm *svm = to_svm(vcpu);

	u64 g_tsc_offset = 0;



	if (is_nested(svm)) {

		g_tsc_offset = svm->vmcb->control.tsc_offset -

			       svm->nested.hsave->control.tsc_offset;

		svm->nested.hsave->control.tsc_offset = offset;

	}



	svm->vmcb->control.tsc_offset = offset + g_tsc_offset;

}



static void init_vmcb(struct vcpu_svm *svm)

{

	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -901,7 +915,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 
	svm->vmcb_pa = page_to_pfn(page) << PAGE_SHIFT;

	svm->asid_generation = 0;

	init_vmcb(svm);

	svm->vmcb->control.tsc_offset = 0-native_read_tsc();

	svm_write_tsc_offset(&svm->vcpu, 0-native_read_tsc());



	err = fx_init(&svm->vcpu);

	if (err)
@@ -2566,20 +2580,9 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data) 
	struct vcpu_svm *svm = to_svm(vcpu);



	switch (ecx) {

	case MSR_IA32_TSC: {

		u64 tsc_offset = data - native_read_tsc();

		u64 g_tsc_offset = 0;



		if (is_nested(svm)) {

			g_tsc_offset = svm->vmcb->control.tsc_offset -

				       svm->nested.hsave->control.tsc_offset;

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

		}



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



	case MSR_IA32_TSC:

		svm_write_tsc_offset(vcpu, data - native_read_tsc());

		break;

	}

	case MSR_STAR:

		svm->vmcb->save.star = data;

		break;

arch/x86/kvm/vmx.c

+5 −6
Original line number Diff line number Diff line
@@ -1149,9 +1149,9 @@ static u64 guest_read_tsc(void) 
 * writes 'guest_tsc' into guest's timestamp counter "register"

 * guest_tsc = host_tsc + tsc_offset ==> tsc_offset = guest_tsc - host_tsc

 */

static void guest_write_tsc(u64 guest_tsc, u64 host_tsc)

static void vmx_write_tsc_offset(u64 offset)

{

	vmcs_write64(TSC_OFFSET, guest_tsc - host_tsc);

	vmcs_write64(TSC_OFFSET, offset);

}



/*
@@ -1255,7 +1255,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) 
		break;

	case MSR_IA32_TSC:

		rdtscll(host_tsc);

		guest_write_tsc(data, host_tsc);

		vmx_write_tsc_offset(data - host_tsc);

		break;

	case MSR_IA32_CR_PAT:

		if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
@@ -2512,7 +2512,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) 
{

	u32 host_sysenter_cs, msr_low, msr_high;

	u32 junk;

	u64 host_pat, tsc_this;

	u64 host_pat;

	unsigned long a;

	struct desc_ptr dt;

	int i;
@@ -2653,8 +2653,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) 
		vmx->vcpu.arch.cr4_guest_owned_bits |= X86_CR4_PGE;

	vmcs_writel(CR4_GUEST_HOST_MASK, ~vmx->vcpu.arch.cr4_guest_owned_bits);



	tsc_this = native_read_tsc();

	guest_write_tsc(0, tsc_this);

	vmx_write_tsc_offset(0-native_read_tsc());



	return 0;

}