[PATCH v2 2/4] KVM: nVMX: Invert 'unsupported by eVMCSv1' check

From: Vitaly Kuznetsov
Date: Fri Nov 04 2022 - 10:48:32 EST

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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@xxxxxxxxxx>
---
arch/x86/kvm/vmx/evmcs.c | 42 +++++++++----------
arch/x86/kvm/vmx/evmcs.h | 90 +++++++++++++++++++++++++++++++++-------
2 files changed, 96 insertions(+), 36 deletions(-)

diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c
index 337783675731..0f031d27741a 100644
--- a/arch/x86/kvm/vmx/evmcs.c
+++ b/arch/x86/kvm/vmx/evmcs.c
@@ -375,32 +375,32 @@ 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)
@@ -424,7 +424,7 @@ 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
@@ -433,31 +433,31 @@ 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;
}

@@ -467,7 +467,7 @@ 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)
diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
index 6f746ef3c038..4c351f334446 100644
--- a/arch/x86/kvm/vmx/evmcs.h
+++ b/arch/x86/kvm/vmx/evmcs.h
@@ -46,22 +46,82 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs);
* Currently unsupported in KVM:
* GUEST_IA32_RTIT_CTL = 0x00002814,
*/
-#define EVMCS1_UNSUPPORTED_PINCTRL (PIN_BASED_POSTED_INTR | \
- PIN_BASED_VMX_PREEMPTION_TIMER)
-#define EVMCS1_UNSUPPORTED_EXEC_CTRL (CPU_BASED_ACTIVATE_TERTIARY_CONTROLS)
-#define EVMCS1_UNSUPPORTED_2NDEXEC \
- (SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY | \
- SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES | \
- SECONDARY_EXEC_APIC_REGISTER_VIRT | \
- SECONDARY_EXEC_ENABLE_PML | \
- SECONDARY_EXEC_ENABLE_VMFUNC | \
- SECONDARY_EXEC_SHADOW_VMCS | \
+#define EVMCS1_SUPPORTED_PINCTRL \
+ (PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR | \
+ PIN_BASED_EXT_INTR_MASK | \
+ PIN_BASED_NMI_EXITING | \
+ PIN_BASED_VIRTUAL_NMIS)
+
+#define EVMCS1_SUPPORTED_EXEC_CTRL \
+ (CPU_BASED_ALWAYSON_WITHOUT_TRUE_MSR | \
+ CPU_BASED_HLT_EXITING | \
+ CPU_BASED_CR3_LOAD_EXITING | \
+ CPU_BASED_CR3_STORE_EXITING | \
+ CPU_BASED_UNCOND_IO_EXITING | \
+ CPU_BASED_MOV_DR_EXITING | \
+ CPU_BASED_USE_TSC_OFFSETTING | \
+ CPU_BASED_MWAIT_EXITING | \
+ CPU_BASED_MONITOR_EXITING | \
+ CPU_BASED_INVLPG_EXITING | \
+ CPU_BASED_RDPMC_EXITING | \
+ CPU_BASED_INTR_WINDOW_EXITING | \
+ CPU_BASED_CR8_LOAD_EXITING | \
+ CPU_BASED_CR8_STORE_EXITING | \
+ CPU_BASED_RDTSC_EXITING | \
+ CPU_BASED_TPR_SHADOW | \
+ CPU_BASED_USE_IO_BITMAPS | \
+ CPU_BASED_MONITOR_TRAP_FLAG | \
+ CPU_BASED_USE_MSR_BITMAPS | \
+ CPU_BASED_NMI_WINDOW_EXITING | \
+ CPU_BASED_PAUSE_EXITING | \
+ CPU_BASED_ACTIVATE_SECONDARY_CONTROLS)
+
+#define EVMCS1_SUPPORTED_2NDEXEC \
+ (SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE | \
+ SECONDARY_EXEC_WBINVD_EXITING | \
+ SECONDARY_EXEC_ENABLE_VPID | \
+ SECONDARY_EXEC_ENABLE_EPT | \
+ SECONDARY_EXEC_UNRESTRICTED_GUEST | \
+ SECONDARY_EXEC_DESC | \
+ SECONDARY_EXEC_ENABLE_RDTSCP | \
+ SECONDARY_EXEC_ENABLE_INVPCID | \
+ SECONDARY_EXEC_XSAVES | \
+ SECONDARY_EXEC_RDSEED_EXITING | \
+ SECONDARY_EXEC_RDRAND_EXITING | \
SECONDARY_EXEC_TSC_SCALING | \
- SECONDARY_EXEC_PAUSE_LOOP_EXITING)
-#define EVMCS1_UNSUPPORTED_VMEXIT_CTRL \
- (VM_EXIT_SAVE_VMX_PREEMPTION_TIMER)
-#define EVMCS1_UNSUPPORTED_VMENTRY_CTRL (0)
-#define EVMCS1_UNSUPPORTED_VMFUNC (VMX_VMFUNC_EPTP_SWITCHING)
+ SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE | \
+ SECONDARY_EXEC_PT_USE_GPA | \
+ SECONDARY_EXEC_PT_CONCEAL_VMX | \
+ SECONDARY_EXEC_BUS_LOCK_DETECTION | \
+ SECONDARY_EXEC_NOTIFY_VM_EXITING | \
+ SECONDARY_EXEC_ENCLS_EXITING)
+
+#define EVMCS1_SUPPORTED_VMEXIT_CTRL \
+ (VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR | \
+ VM_EXIT_SAVE_DEBUG_CONTROLS | \
+ VM_EXIT_ACK_INTR_ON_EXIT | \
+ VM_EXIT_HOST_ADDR_SPACE_SIZE | \
+ VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL | \
+ VM_EXIT_SAVE_IA32_PAT | \
+ VM_EXIT_LOAD_IA32_PAT | \
+ VM_EXIT_SAVE_IA32_EFER | \
+ VM_EXIT_LOAD_IA32_EFER | \
+ VM_EXIT_CLEAR_BNDCFGS | \
+ VM_EXIT_PT_CONCEAL_PIP | \
+ VM_EXIT_CLEAR_IA32_RTIT_CTL)
+
+#define EVMCS1_SUPPORTED_VMENTRY_CTRL \
+ (VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR | \
+ VM_ENTRY_LOAD_DEBUG_CONTROLS | \
+ VM_ENTRY_IA32E_MODE | \
+ VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL | \
+ VM_ENTRY_LOAD_IA32_PAT | \
+ VM_ENTRY_LOAD_IA32_EFER | \
+ VM_ENTRY_LOAD_BNDCFGS | \
+ VM_ENTRY_PT_CONCEAL_PIP | \
+ VM_ENTRY_LOAD_IA32_RTIT_CTL)
+
+#define EVMCS1_SUPPORTED_VMFUNC (0)

struct evmcs_field {
u16 offset;
--
2.38.1

Next message: Vitaly Kuznetsov: "[PATCH v2 3/4] KVM: nVMX: Prepare to sanitize tertiary execution controls with eVMCS"
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