KVM: nVMX: Advertise support for MSR_IA32_VMX_TRUE_*_CTLS

We already implemented them but failed to advertise them. Currently they
all return the identical values to the capability MSRs they are
augmenting. So there is no change in exposed features yet.

Drop related comments at this chance that are partially incorrect and
redundant anyway.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/uapi/asm/msr-index.h

@@ -558,6 +558,7 @@
 
 /* VMX_BASIC bits and bitmasks */
 #define VMX_BASIC_VMCS_SIZE_SHIFT	32
+#define VMX_BASIC_TRUE_CTLS		(1ULL << 55)
 #define VMX_BASIC_64		0x0001000000000000LLU
 #define VMX_BASIC_MEM_TYPE_SHIFT	50
 #define VMX_BASIC_MEM_TYPE_MASK	0x003c000000000000LLU

arch/x86/kvm/vmx.c

@@ -2265,21 +2265,13 @@ static __init void nested_vmx_setup_ctls_msrs(void)
 	/* pin-based controls */
 	rdmsr(MSR_IA32_VMX_PINBASED_CTLS,
 	      nested_vmx_pinbased_ctls_low, nested_vmx_pinbased_ctls_high);
-	/*
-	 * According to the Intel spec, if bit 55 of VMX_BASIC is off (as it is
-	 * in our case), bits 1, 2 and 4 (i.e., 0x16) must be 1 in this MSR.
-	 */
 	nested_vmx_pinbased_ctls_low |= PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR;
 	nested_vmx_pinbased_ctls_high &= PIN_BASED_EXT_INTR_MASK |
 		PIN_BASED_NMI_EXITING | PIN_BASED_VIRTUAL_NMIS;
 	nested_vmx_pinbased_ctls_high |= PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR |
 		PIN_BASED_VMX_PREEMPTION_TIMER;
 
-	/*
-	 * Exit controls
-	 * If bit 55 of VMX_BASIC is off, bits 0-8 and 10, 11, 13, 14, 16 and
-	 * 17 must be 1.
-	 */
+	/* exit controls */
 	rdmsr(MSR_IA32_VMX_EXIT_CTLS,
 		nested_vmx_exit_ctls_low, nested_vmx_exit_ctls_high);
 	nested_vmx_exit_ctls_low = VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;
@@ -2299,7 +2291,6 @@ static __init void nested_vmx_setup_ctls_msrs(void)
 	/* entry controls */
 	rdmsr(MSR_IA32_VMX_ENTRY_CTLS,
 		nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high);
-	/* If bit 55 of VMX_BASIC is off, bits 0-8 and 12 must be 1. */
 	nested_vmx_entry_ctls_low = VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR;
 	nested_vmx_entry_ctls_high &=
 #ifdef CONFIG_X86_64
@@ -2394,7 +2385,7 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
 		 * guest, and the VMCS structure we give it - not about the
 		 * VMX support of the underlying hardware.
 		 */
-		*pdata = VMCS12_REVISION |
+		*pdata = VMCS12_REVISION | VMX_BASIC_TRUE_CTLS |
 			   ((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
 			   (VMX_BASIC_MEM_TYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
 		break;