x86/kvm/hyper-v: don't allow to turn on unsupported VMX controls for …

…nested guests Sane L1 hypervisors are not supposed to turn any of the unsupported VMX controls on for its guests and nested_vmx_check_controls() checks for that. This is, however, not the case for the controls which are supported on the host but are missing in enlightened VMCS and when eVMCS is in use. It would certainly be possible to add these missing checks to nested_check_vm_execution_controls()/_vm_exit_controls()/.. but it seems preferable to keep eVMCS-specific stuff in eVMCS and reduce the impact on non-eVMCS guests by doing less unrelated checks. Create a separate nested_evmcs_check_controls() for this purpose. Signed-off-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
laijs · Feb 5, 2020 · a835023 · a835023
1 parent 31de3d2
commit a835023
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diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c
@@ -7,6 +7,7 @@
 #include "evmcs.h"
 #include "vmcs.h"
 #include "vmx.h"
+#include "trace.h"
 
 DEFINE_STATIC_KEY_FALSE(enable_evmcs);
 
@@ -372,6 +373,58 @@ void nested_evmcs_filter_control_msr(u32 msr_index, u64 *pdata)
 	*pdata = ctl_low | ((u64)ctl_high << 32);
 }
 
+int nested_evmcs_check_controls(struct vmcs12 *vmcs12)
+{
+	int ret = 0;
+	u32 unsupp_ctl;
+
+	unsupp_ctl = vmcs12->pin_based_vm_exec_control &
+		EVMCS1_UNSUPPORTED_PINCTRL;
+	if (unsupp_ctl) {
+		trace_kvm_nested_vmenter_failed(
+			"eVMCS: unsupported pin-based VM-execution controls",
+			unsupp_ctl);
+		ret = -EINVAL;
+	}
+
+	unsupp_ctl = vmcs12->secondary_vm_exec_control &
+		EVMCS1_UNSUPPORTED_2NDEXEC;
+	if (unsupp_ctl) {
+		trace_kvm_nested_vmenter_failed(
+			"eVMCS: unsupported secondary VM-execution controls",
+			unsupp_ctl);
+		ret = -EINVAL;
+	}
+
+	unsupp_ctl = vmcs12->vm_exit_controls &
+		EVMCS1_UNSUPPORTED_VMEXIT_CTRL;
+	if (unsupp_ctl) {
+		trace_kvm_nested_vmenter_failed(
+			"eVMCS: unsupported VM-exit controls",
+			unsupp_ctl);
+		ret = -EINVAL;
+	}
+
+	unsupp_ctl = vmcs12->vm_entry_controls &
+		EVMCS1_UNSUPPORTED_VMENTRY_CTRL;
+	if (unsupp_ctl) {
+		trace_kvm_nested_vmenter_failed(
+			"eVMCS: unsupported VM-entry controls",
+			unsupp_ctl);
+		ret = -EINVAL;
+	}
+
+	unsupp_ctl = vmcs12->vm_function_control & EVMCS1_UNSUPPORTED_VMFUNC;
+	if (unsupp_ctl) {
+		trace_kvm_nested_vmenter_failed(
+			"eVMCS: unsupported VM-function controls",
+			unsupp_ctl);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 			uint16_t *vmcs_version)
 {

diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
@@ -10,6 +10,7 @@
 
 #include "capabilities.h"
 #include "vmcs.h"
+#include "vmcs12.h"
 
 struct vmcs_config;
 
@@ -202,5 +203,6 @@ uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu);
 int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 			uint16_t *vmcs_version);
 void nested_evmcs_filter_control_msr(u32 msr_index, u64 *pdata);
+int nested_evmcs_check_controls(struct vmcs12 *vmcs12);
 
 #endif /* __KVM_X86_VMX_EVMCS_H */
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
@@ -2757,6 +2757,9 @@ static int nested_vmx_check_controls(struct kvm_vcpu *vcpu,
 	    nested_check_vm_entry_controls(vcpu, vmcs12))
 		return -EINVAL;
 
+	if (to_vmx(vcpu)->nested.enlightened_vmcs_enabled)
+		return nested_evmcs_check_controls(vmcs12);
+
 	return 0;
 }