KVM: VMX: Add lazy FPU support for VT
Only save/restore the FPU host state when the guest is actually using the FPU. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
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@ -101,6 +101,13 @@ static inline int is_page_fault(u32 intr_info)
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(INTR_TYPE_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
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}
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static inline int is_no_device(u32 intr_info)
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{
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return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
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INTR_INFO_VALID_MASK)) ==
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(INTR_TYPE_EXCEPTION | NM_VECTOR | INTR_INFO_VALID_MASK);
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}
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static inline int is_external_interrupt(u32 intr_info)
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{
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return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
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@ -216,6 +223,16 @@ static void vmcs_write64(unsigned long field, u64 value)
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#endif
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}
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static void vmcs_clear_bits(unsigned long field, u32 mask)
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{
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vmcs_writel(field, vmcs_readl(field) & ~mask);
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}
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static void vmcs_set_bits(unsigned long field, u32 mask)
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{
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vmcs_writel(field, vmcs_readl(field) | mask);
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}
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/*
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* Switches to specified vcpu, until a matching vcpu_put(), but assumes
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* vcpu mutex is already taken.
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@ -833,6 +850,11 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
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}
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#endif
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if (!(cr0 & CR0_TS_MASK)) {
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vcpu->fpu_active = 1;
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vmcs_clear_bits(EXCEPTION_BITMAP, CR0_TS_MASK);
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}
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vmcs_writel(CR0_READ_SHADOW, cr0);
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vmcs_writel(GUEST_CR0,
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(cr0 & ~KVM_GUEST_CR0_MASK) | KVM_VM_CR0_ALWAYS_ON);
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@ -842,6 +864,12 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
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static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
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{
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vmcs_writel(GUEST_CR3, cr3);
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if (!(vcpu->cr0 & CR0_TS_MASK)) {
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vcpu->fpu_active = 0;
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vmcs_set_bits(GUEST_CR0, CR0_TS_MASK);
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vmcs_set_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
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}
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}
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static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
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@ -1368,6 +1396,15 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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asm ("int $2");
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return 1;
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}
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if (is_no_device(intr_info)) {
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vcpu->fpu_active = 1;
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vmcs_clear_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
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if (!(vcpu->cr0 & CR0_TS_MASK))
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vmcs_clear_bits(GUEST_CR0, CR0_TS_MASK);
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return 1;
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}
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error_code = 0;
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rip = vmcs_readl(GUEST_RIP);
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if (intr_info & INTR_INFO_DELIEVER_CODE_MASK)
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@ -1556,7 +1593,11 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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break;
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case 2: /* clts */
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vcpu_load_rsp_rip(vcpu);
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set_cr0(vcpu, vcpu->cr0 & ~CR0_TS_MASK);
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vcpu->fpu_active = 1;
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vmcs_clear_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
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vmcs_clear_bits(GUEST_CR0, CR0_TS_MASK);
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vcpu->cr0 &= ~CR0_TS_MASK;
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vmcs_writel(CR0_READ_SHADOW, vcpu->cr0);
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skip_emulated_instruction(vcpu);
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return 1;
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case 1: /*mov from cr*/
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@ -1806,8 +1847,14 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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if (vcpu->guest_debug.enabled)
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kvm_guest_debug_pre(vcpu);
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fx_save(vcpu->host_fx_image);
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fx_restore(vcpu->guest_fx_image);
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if (vcpu->fpu_active) {
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fx_save(vcpu->host_fx_image);
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fx_restore(vcpu->guest_fx_image);
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}
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/*
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* Loading guest fpu may have cleared host cr0.ts
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*/
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vmcs_writel(HOST_CR0, read_cr0());
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#ifdef CONFIG_X86_64
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if (is_long_mode(vcpu)) {
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@ -1965,8 +2012,11 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
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}
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#endif
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fx_save(vcpu->guest_fx_image);
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fx_restore(vcpu->host_fx_image);
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if (vcpu->fpu_active) {
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fx_save(vcpu->guest_fx_image);
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fx_restore(vcpu->host_fx_image);
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}
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vcpu->interrupt_window_open = (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0;
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asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
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@ -2078,6 +2128,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
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vmcs_clear(vmcs);
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vcpu->vmcs = vmcs;
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vcpu->launched = 0;
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vcpu->fpu_active = 1;
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return 0;
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