arch/x86/kvm/vmx/hyperv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   3
   4 #include <linux/errno.h>
   5 #include <linux/smp.h>
   6
   7 #include "../cpuid.h"
   8 #include "hyperv.h"
   9 #include "nested.h"
  10 #include "vmcs.h"
  11 #include "vmx.h"
  12 #include "trace.h"
  13
  14 #define CC KVM_NESTED_VMENTER_CONSISTENCY_CHECK
  15
  16 u64 nested_get_evmptr(struct kvm_vcpu *vcpu)
  17 {
  18         struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
  19
  20         if (unlikely(kvm_hv_get_assist_page(vcpu)))
  21                 return EVMPTR_INVALID;
  22
  23         if (unlikely(!hv_vcpu->vp_assist_page.enlighten_vmentry))
  24                 return EVMPTR_INVALID;
  25
  26         return hv_vcpu->vp_assist_page.current_nested_vmcs;
  27 }
  28
  29 uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu)
  30 {
  31         /*
  32          * vmcs_version represents the range of supported Enlightened VMCS
  33          * versions: lower 8 bits is the minimal version, higher 8 bits is the
  34          * maximum supported version. KVM supports versions from 1 to
  35          * KVM_EVMCS_VERSION.
  36          *
  37          * Note, do not check the Hyper-V is fully enabled in guest CPUID, this
  38          * helper is used to _get_ the vCPU's supported CPUID.
  39          */
  40         if (kvm_cpu_cap_get(X86_FEATURE_VMX) &&
  41             (!vcpu || to_vmx(vcpu)->nested.enlightened_vmcs_enabled))
  42                 return (KVM_EVMCS_VERSION << 8) | 1;
  43
  44         return 0;
  45 }
  46
  47 enum evmcs_revision {
  48         EVMCSv1_LEGACY,
  49         NR_EVMCS_REVISIONS,
  50 };
  51
  52 enum evmcs_ctrl_type {
  53         EVMCS_EXIT_CTRLS,
  54         EVMCS_ENTRY_CTRLS,
  55         EVMCS_EXEC_CTRL,
  56         EVMCS_2NDEXEC,
  57         EVMCS_3RDEXEC,
  58         EVMCS_PINCTRL,
  59         EVMCS_VMFUNC,
  60         NR_EVMCS_CTRLS,
  61 };
  62
  63 static const u32 evmcs_supported_ctrls[NR_EVMCS_CTRLS][NR_EVMCS_REVISIONS] = {
  64         [EVMCS_EXIT_CTRLS] = {
  65                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMEXIT_CTRL,
  66         },
  67         [EVMCS_ENTRY_CTRLS] = {
  68                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMENTRY_CTRL,
  69         },
  70         [EVMCS_EXEC_CTRL] = {
  71                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_EXEC_CTRL,
  72         },
  73         [EVMCS_2NDEXEC] = {
  74                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_2NDEXEC & ~SECONDARY_EXEC_TSC_SCALING,
  75         },
  76         [EVMCS_3RDEXEC] = {
  77                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_3RDEXEC,
  78         },
  79         [EVMCS_PINCTRL] = {
  80                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_PINCTRL,
  81         },
  82         [EVMCS_VMFUNC] = {
  83                 [EVMCSv1_LEGACY] = EVMCS1_SUPPORTED_VMFUNC,
  84         },
  85 };
  86
  87 static u32 evmcs_get_supported_ctls(enum evmcs_ctrl_type ctrl_type)
  88 {
  89         enum evmcs_revision evmcs_rev = EVMCSv1_LEGACY;
  90
  91         return evmcs_supported_ctrls[ctrl_type][evmcs_rev];
  92 }
  93
  94 static bool evmcs_has_perf_global_ctrl(struct kvm_vcpu *vcpu)
  95 {
  96         struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
  97
  98         /*
  99          * PERF_GLOBAL_CTRL has a quirk where some Windows guests may fail to
 100          * boot if a PV CPUID feature flag is not also set.  Treat the fields
 101          * as unsupported if the flag is not set in guest CPUID.  This should
 102          * be called only for guest accesses, and all guest accesses should be
 103          * gated on Hyper-V being enabled and initialized.
 104          */
 105         if (WARN_ON_ONCE(!hv_vcpu))
 106                 return false;
 107
 108         return hv_vcpu->cpuid_cache.nested_ebx & HV_X64_NESTED_EVMCS1_PERF_GLOBAL_CTRL;
 109 }
 110
 111 void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
 112 {
 113         u32 ctl_low = (u32)*pdata;
 114         u32 ctl_high = (u32)(*pdata >> 32);
 115         u32 supported_ctrls;
 116
 117         /*
 118          * Hyper-V 2016 and 2019 try using these features even when eVMCS
 119          * is enabled but there are no corresponding fields.
 120          */
 121         switch (msr_index) {
 122         case MSR_IA32_VMX_EXIT_CTLS:
 123         case MSR_IA32_VMX_TRUE_EXIT_CTLS:
 124                 supported_ctrls = evmcs_get_supported_ctls(EVMCS_EXIT_CTRLS);
 125                 if (!evmcs_has_perf_global_ctrl(vcpu))
 126                         supported_ctrls &= ~VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL;
 127                 ctl_high &= supported_ctrls;
 128                 break;
 129         case MSR_IA32_VMX_ENTRY_CTLS:
 130         case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
 131                 supported_ctrls = evmcs_get_supported_ctls(EVMCS_ENTRY_CTRLS);
 132                 if (!evmcs_has_perf_global_ctrl(vcpu))
 133                         supported_ctrls &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
 134                 ctl_high &= supported_ctrls;
 135                 break;
 136         case MSR_IA32_VMX_PROCBASED_CTLS:
 137         case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
 138                 ctl_high &= evmcs_get_supported_ctls(EVMCS_EXEC_CTRL);
 139                 break;
 140         case MSR_IA32_VMX_PROCBASED_CTLS2:
 141                 ctl_high &= evmcs_get_supported_ctls(EVMCS_2NDEXEC);
 142                 break;
 143         case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
 144         case MSR_IA32_VMX_PINBASED_CTLS:
 145                 ctl_high &= evmcs_get_supported_ctls(EVMCS_PINCTRL);
 146                 break;
 147         case MSR_IA32_VMX_VMFUNC:
 148                 ctl_low &= evmcs_get_supported_ctls(EVMCS_VMFUNC);
 149                 break;
 150         }
 151
 152         *pdata = ctl_low | ((u64)ctl_high << 32);
 153 }
 154
 155 static bool nested_evmcs_is_valid_controls(enum evmcs_ctrl_type ctrl_type,
 156                                            u32 val)
 157 {
 158         return !(val & ~evmcs_get_supported_ctls(ctrl_type));
 159 }
 160
 161 int nested_evmcs_check_controls(struct vmcs12 *vmcs12)
 162 {
 163         if (CC(!nested_evmcs_is_valid_controls(EVMCS_PINCTRL,
 164                                                vmcs12->pin_based_vm_exec_control)))
 165                 return -EINVAL;
 166
 167         if (CC(!nested_evmcs_is_valid_controls(EVMCS_EXEC_CTRL,
 168                                                vmcs12->cpu_based_vm_exec_control)))
 169                 return -EINVAL;
 170
 171         if (CC(!nested_evmcs_is_valid_controls(EVMCS_2NDEXEC,
 172                                                vmcs12->secondary_vm_exec_control)))
 173                 return -EINVAL;
 174
 175         if (CC(!nested_evmcs_is_valid_controls(EVMCS_EXIT_CTRLS,
 176                                                vmcs12->vm_exit_controls)))
 177                 return -EINVAL;
 178
 179         if (CC(!nested_evmcs_is_valid_controls(EVMCS_ENTRY_CTRLS,
 180                                                vmcs12->vm_entry_controls)))
 181                 return -EINVAL;
 182
 183         /*
 184          * VM-Func controls are 64-bit, but KVM currently doesn't support any
 185          * controls in bits 63:32, i.e. dropping those bits on the consistency
 186          * check is intentional.
 187          */
 188         if (WARN_ON_ONCE(vmcs12->vm_function_control >> 32))
 189                 return -EINVAL;
 190
 191         if (CC(!nested_evmcs_is_valid_controls(EVMCS_VMFUNC,
 192                                                vmcs12->vm_function_control)))
 193                 return -EINVAL;
 194
 195         return 0;
 196 }
 197
 198 int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 199                         uint16_t *vmcs_version)
 200 {
 201         struct vcpu_vmx *vmx = to_vmx(vcpu);
 202
 203         vmx->nested.enlightened_vmcs_enabled = true;
 204
 205         if (vmcs_version)
 206                 *vmcs_version = nested_get_evmcs_version(vcpu);
 207
 208         return 0;
 209 }
 210
 211 bool nested_evmcs_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu)
 212 {
 213         struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
 214         struct vcpu_vmx *vmx = to_vmx(vcpu);
 215         struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
 216
 217         if (!hv_vcpu || !evmcs)
 218                 return false;
 219
 220         if (!evmcs->hv_enlightenments_control.nested_flush_hypercall)
 221                 return false;
 222
 223         return hv_vcpu->vp_assist_page.nested_control.features.directhypercall;
 224 }
 225
 226 void vmx_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu)
 227 {
 228         nested_vmx_vmexit(vcpu, HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH, 0, 0);
 229 }