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KVM: VMX: Move skip_emulated_instruction out of nested_vmx_check_vmcs12
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We can't return both the pass/fail boolean for the vmcs and the upcoming
continue/exit-to-userspace boolean for skip_emulated_instruction out of
nested_vmx_check_vmcs, so move skip_emulated_instruction out of it instead.

Additionally, VMENTER/VMRESUME only trigger singlestep exceptions when
they advance the IP to the following instruction, not when they a) succeed,
b) fail MSR validation or c) throw an exception. Add a separate call to
skip_emulated_instruction that will later not be converted to the variant
that checks the singlestep flag.

Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
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Kyle Huey authored and Paolo Bonzini committed Dec 8, 2016
1 parent 09ca3f2 commit eb27756
Showing 1 changed file with 33 additions and 20 deletions.
53 changes: 33 additions & 20 deletions arch/x86/kvm/vmx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7324,7 +7324,6 @@ static int nested_vmx_check_vmcs12(struct kvm_vcpu *vcpu)
struct vcpu_vmx *vmx = to_vmx(vcpu);
if (vmx->nested.current_vmptr == -1ull) {
nested_vmx_failInvalid(vcpu);
skip_emulated_instruction(vcpu);
return 0;
}
return 1;
Expand All @@ -7338,9 +7337,13 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
gva_t gva = 0;

if (!nested_vmx_check_permission(vcpu) ||
!nested_vmx_check_vmcs12(vcpu))
if (!nested_vmx_check_permission(vcpu))
return 1;

if (!nested_vmx_check_vmcs12(vcpu)) {
skip_emulated_instruction(vcpu);
return 1;
}

/* Decode instruction info and find the field to read */
field = kvm_register_readl(vcpu, (((vmx_instruction_info) >> 28) & 0xf));
Expand Down Expand Up @@ -7388,10 +7391,14 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
u64 field_value = 0;
struct x86_exception e;

if (!nested_vmx_check_permission(vcpu) ||
!nested_vmx_check_vmcs12(vcpu))
if (!nested_vmx_check_permission(vcpu))
return 1;

if (!nested_vmx_check_vmcs12(vcpu)) {
skip_emulated_instruction(vcpu);
return 1;
}

if (vmx_instruction_info & (1u << 10))
field_value = kvm_register_readl(vcpu,
(((vmx_instruction_info) >> 3) & 0xf));
Expand Down Expand Up @@ -10046,11 +10053,12 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
bool ia32e;
u32 msr_entry_idx;

if (!nested_vmx_check_permission(vcpu) ||
!nested_vmx_check_vmcs12(vcpu))
if (!nested_vmx_check_permission(vcpu))
return 1;

skip_emulated_instruction(vcpu);
if (!nested_vmx_check_vmcs12(vcpu))
goto out;

vmcs12 = get_vmcs12(vcpu);

if (enable_shadow_vmcs)
Expand All @@ -10070,33 +10078,33 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
nested_vmx_failValid(vcpu,
launch ? VMXERR_VMLAUNCH_NONCLEAR_VMCS
: VMXERR_VMRESUME_NONLAUNCHED_VMCS);
return 1;
goto out;
}

if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (nested_vmx_check_msr_bitmap_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (nested_vmx_check_apicv_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (nested_vmx_check_msr_switch_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (!vmx_control_verify(vmcs12->cpu_based_vm_exec_control,
Expand All @@ -10116,26 +10124,26 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
vmx->nested.nested_vmx_entry_ctls_high))
{
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
goto out;
}

if (((vmcs12->host_cr0 & VMXON_CR0_ALWAYSON) != VMXON_CR0_ALWAYSON) ||
((vmcs12->host_cr4 & VMXON_CR4_ALWAYSON) != VMXON_CR4_ALWAYSON)) {
nested_vmx_failValid(vcpu,
VMXERR_ENTRY_INVALID_HOST_STATE_FIELD);
return 1;
goto out;
}

if (!nested_cr0_valid(vcpu, vmcs12->guest_cr0) ||
((vmcs12->guest_cr4 & VMXON_CR4_ALWAYSON) != VMXON_CR4_ALWAYSON)) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
return 1;
goto out;
}
if (vmcs12->vmcs_link_pointer != -1ull) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_VMCS_LINK_PTR);
return 1;
goto out;
}

/*
Expand All @@ -10155,7 +10163,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
ia32e != !!(vmcs12->guest_ia32_efer & EFER_LME))) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
return 1;
goto out;
}
}

Expand All @@ -10173,7 +10181,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
ia32e != !!(vmcs12->host_ia32_efer & EFER_LME)) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
return 1;
goto out;
}
}

Expand All @@ -10186,6 +10194,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
if (!vmcs02)
return -ENOMEM;

skip_emulated_instruction(vcpu);
enter_guest_mode(vcpu);

if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
Expand Down Expand Up @@ -10227,6 +10236,10 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
* the success flag) when L2 exits (see nested_vmx_vmexit()).
*/
return 1;

out:
skip_emulated_instruction(vcpu);
return 1;
}

/*
Expand Down

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