KVM: nVMX: Invert 'unsupported by eVMCSv1' check

When a new feature gets implemented in KVM, EVMCS1_UNSUPPORTED_* defines
need to be adjusted to avoid the situation when the feature is exposed
to the guest but there's no corresponding eVMCS field[s] for it. This
is not obvious and fragile. Invert 'unsupported by eVMCSv1' check and
make it 'supported by eVMCSv1' instead, this way it's much harder to
make a mistake. New features will get added to EVMCS1_SUPPORTED_*
defines when the corresponding fields are added to eVMCS definition.

No functional change intended. EVMCS1_SUPPORTED_* defines are composed
by taking KVM_{REQUIRED,OPTIONAL}_VMX_ defines and filtering out what
was previously known as EVMCS1_UNSUPPORTED_*.

From all the controls, SECONDARY_EXEC_TSC_SCALING requires special
handling as it's actually present in eVMCSv1 definition but is not
currently supported for Hyper-V-on-KVM, just for KVM-on-Hyper-V. As
evmcs_supported_ctrls will be used for both scenarios, just add it
there instead of EVMCS1_SUPPORTED_2NDEXEC.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20221104144708.435865-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 21 insertions, 21 deletions

diff --git a/arch/x86/kvm/vmx/hyperv.c b/arch/x86/kvm/vmx/hyperv.c
index 04ea0259ab7f..77027f6a9b41 100644
--- a/arch/x86/kvm/vmx/hyperv.c
+++ b/arch/x86/kvm/vmx/hyperv.c
@@ -368,32 +368,32 @@ enum evmcs_ctrl_type {
 	NR_EVMCS_CTRLS,
 };
 
-static const u32 evmcs_unsupported_ctrls[NR_EVMCS_CTRLS][NR_EVMCS_REVISIONS] = {
+static const u32 evmcs_supported_ctrls[NR_EVMCS_CTRLS][NR_EVMCS_REVISIONS] = {
 	[EVMCS_EXIT_CTRLS] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_VMEXIT_CTRL,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMEXIT_CTRL,
 	},
 	[EVMCS_ENTRY_CTRLS] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_VMENTRY_CTRL,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMENTRY_CTRL,
 	},
 	[EVMCS_EXEC_CTRL] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_EXEC_CTRL,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_EXEC_CTRL,
 	},
 	[EVMCS_2NDEXEC] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_2NDEXEC,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_2NDEXEC & ~SECONDARY_EXEC_TSC_SCALING,
 	},
 	[EVMCS_PINCTRL] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_PINCTRL,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_PINCTRL,
 	},
 	[EVMCS_VMFUNC] = {
-		[EVMCSv1_LEGACY] = EVMCS1_UNSUPPORTED_VMFUNC,
+		[EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMFUNC,
 	},
 };
 
-static u32 evmcs_get_unsupported_ctls(enum evmcs_ctrl_type ctrl_type)
+static u32 evmcs_get_supported_ctls(enum evmcs_ctrl_type ctrl_type)
 {
 	enum evmcs_revision evmcs_rev = EVMCSv1_LEGACY;
 
-	return evmcs_unsupported_ctrls[ctrl_type][evmcs_rev];
+	return evmcs_supported_ctrls[ctrl_type][evmcs_rev];
 }
 
 static bool evmcs_has_perf_global_ctrl(struct kvm_vcpu *vcpu)
@@ -417,7 +417,7 @@ void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *
 {
 	u32 ctl_low = (u32)*pdata;
 	u32 ctl_high = (u32)(*pdata >> 32);
-	u32 unsupported_ctrls;
+	u32 supported_ctrls;
 
 	/*
 	 * Hyper-V 2016 and 2019 try using these features even when eVMCS
@@ -426,31 +426,31 @@ void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *
 	switch (msr_index) {
 	case MSR_IA32_VMX_EXIT_CTLS:
 	case MSR_IA32_VMX_TRUE_EXIT_CTLS:
-		unsupported_ctrls = evmcs_get_unsupported_ctls(EVMCS_EXIT_CTRLS);
+		supported_ctrls = evmcs_get_supported_ctls(EVMCS_EXIT_CTRLS);
 		if (!evmcs_has_perf_global_ctrl(vcpu))
-			unsupported_ctrls |= VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
-		ctl_high &= ~unsupported_ctrls;
+			supported_ctrls &= ~VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
+		ctl_high &= supported_ctrls;
 		break;
 	case MSR_IA32_VMX_ENTRY_CTLS:
 	case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
-		unsupported_ctrls = evmcs_get_unsupported_ctls(EVMCS_ENTRY_CTRLS);
+		supported_ctrls = evmcs_get_supported_ctls(EVMCS_ENTRY_CTRLS);
 		if (!evmcs_has_perf_global_ctrl(vcpu))
-			unsupported_ctrls |= VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
-		ctl_high &= ~unsupported_ctrls;
+			supported_ctrls &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
+		ctl_high &= supported_ctrls;
 		break;
 	case MSR_IA32_VMX_PROCBASED_CTLS:
 	case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
-		ctl_high &= ~evmcs_get_unsupported_ctls(EVMCS_EXEC_CTRL);
+		ctl_high &= evmcs_get_supported_ctls(EVMCS_EXEC_CTRL);
 		break;
 	case MSR_IA32_VMX_PROCBASED_CTLS2:
-		ctl_high &= ~evmcs_get_unsupported_ctls(EVMCS_2NDEXEC);
+		ctl_high &= evmcs_get_supported_ctls(EVMCS_2NDEXEC);
 		break;
 	case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
 	case MSR_IA32_VMX_PINBASED_CTLS:
-		ctl_high &= ~evmcs_get_unsupported_ctls(EVMCS_PINCTRL);
+		ctl_high &= evmcs_get_supported_ctls(EVMCS_PINCTRL);
 		break;
 	case MSR_IA32_VMX_VMFUNC:
-		ctl_low &= ~evmcs_get_unsupported_ctls(EVMCS_VMFUNC);
+		ctl_low &= evmcs_get_supported_ctls(EVMCS_VMFUNC);
 		break;
 	}
 
@@ -460,7 +460,7 @@ void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *
 static bool nested_evmcs_is_valid_controls(enum evmcs_ctrl_type ctrl_type,
 					   u32 val)
 {
-	return !(val & evmcs_get_unsupported_ctls(ctrl_type));
+	return !(val & ~evmcs_get_supported_ctls(ctrl_type));
 }
 
 int nested_evmcs_check_controls(struct vmcs12 *vmcs12)