Re: [PATCH 10/14] KVM: x86: Make Hyper-V emulation optional

From: Maxim Levitsky
Date: Tue Nov 07 2023 - 13:26:39 EST

On Wed, 2023-10-25 at 17:24 +0200, Vitaly Kuznetsov wrote:
> Hyper-V emulation in KVM is a fairly big chunk and in some cases it may be
> desirable to not compile it in to reduce module sizes as well as the attack
> surface. Introduce CONFIG_KVM_HYPERV option to make it possible.
>
> Note, there's room for further nVMX/nSVM code optimizations when
> !CONFIG_KVM_HYPERV, this will be done in follow-up patches.
>
> Reorganize Makefile a bit so all CONFIG_HYPERV and CONFIG_KVM_HYPERV files
> are grouped together.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 4 +++
> arch/x86/kvm/Kconfig | 14 ++++++++
> arch/x86/kvm/Makefile | 23 ++++++------
> arch/x86/kvm/cpuid.c | 6 ++++
> arch/x86/kvm/hyperv.h | 30 ++++++++++++++--
> arch/x86/kvm/irq_comm.c | 9 ++++-
> arch/x86/kvm/svm/hyperv.h | 7 ++++
> arch/x86/kvm/vmx/hyperv.h | 8 +++++
> arch/x86/kvm/vmx/nested.c | 15 ++++++++
> arch/x86/kvm/x86.c | 62 ++++++++++++++++++++++++---------
> 10 files changed, 147 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 7fb2810f4573..e5b881dda747 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1095,6 +1095,7 @@ enum hv_tsc_page_status {
> HV_TSC_PAGE_BROKEN,
> };
>
> +#ifdef CONFIG_KVM_HYPERV
> /* Hyper-V emulation context */
> struct kvm_hv {
> struct mutex hv_lock;
> @@ -1127,6 +1128,7 @@ struct kvm_hv {
>
> struct kvm_hv_syndbg hv_syndbg;
> };
> +#endif
>
> struct msr_bitmap_range {
> u32 flags;
> @@ -1349,7 +1351,9 @@ struct kvm_arch {
> /* reads protected by irq_srcu, writes by irq_lock */
> struct hlist_head mask_notifier_list;
>
> +#ifdef CONFIG_KVM_HYPERV
> struct kvm_hv hyperv;
> +#endif
>
> #ifdef CONFIG_KVM_XEN
> struct kvm_xen xen;
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 950c12868d30..93930cef9b3b 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -129,6 +129,20 @@ config KVM_SMM
>
> If unsure, say Y.
>
> +config KVM_HYPERV
> + bool "Support for Microsoft Hyper-V emulation"
> + depends on KVM
> + default y
> + help
> + Provides KVM support for emulating Microsoft Hyper-V. This allows KVM
> + to expose a subset of the paravirtualized interfaces defined in the
> + Hyper-V Hypervisor Top-Level Functional Specification (TLFS):
> + https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs
> + These interfaces are required for the correct and performant functioning
> + of Windows and Hyper-V guests on KVM.
Looks very good.

> +
> + If unsure, say "Y".
> +
> config KVM_XEN
> bool "Support for Xen hypercall interface"
> depends on KVM
> diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
> index 8ea872401cd6..b97b875ad75f 100644
> --- a/arch/x86/kvm/Makefile
> +++ b/arch/x86/kvm/Makefile
> @@ -11,32 +11,33 @@ include $(srctree)/virt/kvm/Makefile.kvm
>
> kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \
> i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
> - hyperv.o debugfs.o mmu/mmu.o mmu/page_track.o \
> + debugfs.o mmu/mmu.o mmu/page_track.o \
> mmu/spte.o
>
> -ifdef CONFIG_HYPERV
> -kvm-y += kvm_onhyperv.o
> -endif
> -
> kvm-$(CONFIG_X86_64) += mmu/tdp_iter.o mmu/tdp_mmu.o
> +kvm-$(CONFIG_KVM_HYPERV) += hyperv.o
> kvm-$(CONFIG_KVM_XEN) += xen.o
> kvm-$(CONFIG_KVM_SMM) += smm.o
>
> kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
> - vmx/hyperv.o vmx/hyperv_evmcs.o vmx/nested.o vmx/posted_intr.o
> -kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
> + vmx/nested.o vmx/posted_intr.o
>
> -ifdef CONFIG_HYPERV
> -kvm-intel-y += vmx/vmx_onhyperv.o
> -endif
> +kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
>
> kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o \
> - svm/sev.o svm/hyperv.o
> + svm/sev.o
>
> ifdef CONFIG_HYPERV
> +kvm-y += kvm_onhyperv.o
> +kvm-intel-y += vmx/vmx_onhyperv.o vmx/hyperv_evmcs.o
> kvm-amd-y += svm/svm_onhyperv.o
> endif
>
> +ifdef CONFIG_KVM_HYPERV
> +kvm-intel-y += vmx/hyperv.o vmx/hyperv_evmcs.o
> +kvm-amd-y += svm/hyperv.o
> +endif
> +
> obj-$(CONFIG_KVM) += kvm.o
> obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
> obj-$(CONFIG_KVM_AMD) += kvm-amd.o

This also looks much better.

> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 464b23ac5f93..da8e0873f63a 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -314,11 +314,15 @@ EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime);
>
> static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent)
> {
> +#ifdef CONFIG_KVM_HYPERV
> struct kvm_cpuid_entry2 *entry;
>
> entry = cpuid_entry2_find(entries, nent, HYPERV_CPUID_INTERFACE,
> KVM_CPUID_INDEX_NOT_SIGNIFICANT);
> return entry && entry->eax == HYPERV_CPUID_SIGNATURE_EAX;
> +#else
> + return false;
> +#endif
> }
>
> static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> @@ -433,11 +437,13 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
> return 0;
> }
>
> +#ifdef CONFIG_KVM_HYPERV
> if (kvm_cpuid_has_hyperv(e2, nent)) {
> r = kvm_hv_vcpu_init(vcpu);
> if (r)
> return r;
> }
> +#endif
>
> r = kvm_check_cpuid(vcpu, e2, nent);
> if (r)
> diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
> index 75dcbe598fbc..5c5ec7015136 100644
> --- a/arch/x86/kvm/hyperv.h
> +++ b/arch/x86/kvm/hyperv.h
> @@ -24,6 +24,8 @@
> #include <linux/kvm_host.h>
> #include "x86.h"
>
> +#ifdef CONFIG_KVM_HYPERV
> +
> /* "Hv#1" signature */
> #define HYPERV_CPUID_SIGNATURE_EAX 0x31237648
>
> @@ -259,5 +261,29 @@ static inline void kvm_hv_nested_transtion_tlb_flush(struct kvm_vcpu *vcpu, bool
> }
>
> int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu);
> -
> -#endif
> +#else /* CONFIG_KVM_HYPERV */
> +static inline void kvm_hv_setup_tsc_page(struct kvm *kvm,
> + struct pvclock_vcpu_time_info *hv_clock) {}
> +static inline void kvm_hv_request_tsc_page_update(struct kvm *kvm) {}
> +static inline void kvm_hv_init_vm(struct kvm *kvm) {}
> +static inline void kvm_hv_destroy_vm(struct kvm *kvm) {}
> +static inline int kvm_hv_vcpu_init(struct kvm_vcpu *vcpu) { return 0; }
> +static inline void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu) {}
> +static inline bool kvm_hv_hypercall_enabled(struct kvm_vcpu *vcpu) { return false; }
> +static inline int kvm_hv_hypercall(struct kvm_vcpu *vcpu) { return HV_STATUS_ACCESS_DENIED; }
> +static inline void kvm_hv_vcpu_purge_flush_tlb(struct kvm_vcpu *vcpu) {}
> +static inline void kvm_hv_free_pa_page(struct kvm *kvm) {}
> +static inline bool kvm_hv_synic_has_vector(struct kvm_vcpu *vcpu, int vector) { return false; }
> +static inline bool kvm_hv_synic_auto_eoi_set(struct kvm_vcpu *vcpu, int vector) { return false; }
> +static inline void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector) {}
> +static inline bool kvm_hv_invtsc_suppressed(struct kvm_vcpu *vcpu) { return false; }
> +static inline void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu, bool hyperv_enabled) {}
> +static inline bool kvm_hv_has_stimer_pending(struct kvm_vcpu *vcpu) { return false; }
> +static inline bool kvm_hv_is_tlb_flush_hcall(struct kvm_vcpu *vcpu) { return false; }
> +static inline bool guest_hv_cpuid_has_l2_tlb_flush(struct kvm_vcpu *vcpu) { return false; }
> +static inline int kvm_hv_verify_vp_assist(struct kvm_vcpu *vcpu) { return 0; }
> +static inline u32 kvm_hv_get_vpindex(struct kvm_vcpu *vcpu) { return vcpu->vcpu_idx; }
> +static inline void kvm_hv_nested_transtion_tlb_flush(struct kvm_vcpu *vcpu, bool tdp_enabled) {}
> +#endif /* CONFIG_KVM_HYPERV */
> +
> +#endif /* __ARCH_X86_KVM_HYPERV_H__ */


> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> index 16d076a1b91a..68f3f6c26046 100644
> --- a/arch/x86/kvm/irq_comm.c
> +++ b/arch/x86/kvm/irq_comm.c
> @@ -144,7 +144,7 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
> return kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
> }
>
> -
> +#ifdef CONFIG_KVM_HYPERV
> static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
> struct kvm *kvm, int irq_source_id, int level,
> bool line_status)
> @@ -154,6 +154,7 @@ static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
>
> return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint);
> }
> +#endif
>
> int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
> struct kvm *kvm, int irq_source_id, int level,
> @@ -163,9 +164,11 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
> int r;
>
> switch (e->type) {
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_IRQ_ROUTING_HV_SINT:
> return kvm_hv_set_sint(e, kvm, irq_source_id, level,
> line_status);
> +#endif
>
> case KVM_IRQ_ROUTING_MSI:
> if (kvm_msi_route_invalid(kvm, e))
> @@ -314,11 +317,13 @@ int kvm_set_routing_entry(struct kvm *kvm,
> if (kvm_msi_route_invalid(kvm, e))
> return -EINVAL;
> break;
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_IRQ_ROUTING_HV_SINT:
> e->set = kvm_hv_set_sint;
> e->hv_sint.vcpu = ue->u.hv_sint.vcpu;
> e->hv_sint.sint = ue->u.hv_sint.sint;
> break;
> +#endif
> #ifdef CONFIG_KVM_XEN
> case KVM_IRQ_ROUTING_XEN_EVTCHN:
> return kvm_xen_setup_evtchn(kvm, e, ue);
> @@ -438,5 +443,7 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
>
> void kvm_arch_irq_routing_update(struct kvm *kvm)
> {
> +#ifdef CONFIG_KVM_HYPERV
> kvm_hv_irq_routing_update(kvm);
> +#endif
> }
> diff --git a/arch/x86/kvm/svm/hyperv.h b/arch/x86/kvm/svm/hyperv.h
> index 02f4784b5d44..14eec2d9b6be 100644
> --- a/arch/x86/kvm/svm/hyperv.h
> +++ b/arch/x86/kvm/svm/hyperv.h
> @@ -11,6 +11,7 @@
> #include "../hyperv.h"
> #include "svm.h"
>
> +#ifdef CONFIG_KVM_HYPERV
> static inline void nested_svm_hv_update_vm_vp_ids(struct kvm_vcpu *vcpu)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
> @@ -41,5 +42,11 @@ static inline bool nested_svm_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu)
> }
>
> void svm_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu);
> +#else /* CONFIG_KVM_HYPERV */
> +static inline void nested_svm_hv_update_vm_vp_ids(struct kvm_vcpu *vcpu) {}
> +static inline bool nested_svm_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu) { return false; }
> +static inline void svm_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu) {}
> +#endif /* CONFIG_KVM_HYPERV */
> +
>
> #endif /* __ARCH_X86_KVM_SVM_HYPERV_H__ */
> diff --git a/arch/x86/kvm/vmx/hyperv.h b/arch/x86/kvm/vmx/hyperv.h
> index d4ed99008518..933ef6cad5e6 100644
> --- a/arch/x86/kvm/vmx/hyperv.h
> +++ b/arch/x86/kvm/vmx/hyperv.h
> @@ -20,6 +20,7 @@ enum nested_evmptrld_status {
> EVMPTRLD_ERROR,
> };
>
> +#ifdef CONFIG_KVM_HYPERV
> u64 nested_get_evmptr(struct kvm_vcpu *vcpu);
> uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu);
> int nested_enable_evmcs(struct kvm_vcpu *vcpu,
> @@ -28,5 +29,12 @@ void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *
> int nested_evmcs_check_controls(struct vmcs12 *vmcs12);
> bool nested_evmcs_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu);
> void vmx_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu);
> +#else
> +static inline u64 nested_get_evmptr(struct kvm_vcpu *vcpu) { return EVMPTR_INVALID; }
> +static inline void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) {}
> +static inline bool nested_evmcs_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu) { return false; }
> +static inline int nested_evmcs_check_controls(struct vmcs12 *vmcs12) { return 0; }
> +#endif
> +
>
> #endif /* __KVM_X86_VMX_HYPERV_H */
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 382c0746d069..d0d735974b2c 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -226,6 +226,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx)
>
> static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
> {
> +#ifdef CONFIG_KVM_HYPERV
> struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
> struct vcpu_vmx *vmx = to_vmx(vcpu);
>
> @@ -241,6 +242,7 @@ static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
> hv_vcpu->nested.vm_id = 0;
> hv_vcpu->nested.vp_id = 0;
> }
> +#endif
> }
>
> static void vmx_sync_vmcs_host_state(struct vcpu_vmx *vmx,
> @@ -1570,6 +1572,7 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx)
> vmcs_load(vmx->loaded_vmcs->vmcs);
> }
>
> +#ifdef CONFIG_KVM_HYPERV
> static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields)
> {
> struct vmcs12 *vmcs12 = vmx->nested.cached_vmcs12;
> @@ -2077,6 +2080,10 @@ static enum nested_evmptrld_status nested_vmx_handle_enlightened_vmptrld(
>
> return EVMPTRLD_SUCCEEDED;
> }
> +#else /* CONFIG_KVM_HYPERV */
> +static inline void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields) {}
> +static inline void copy_vmcs12_to_enlightened(struct vcpu_vmx *vmx) {}
> +#endif /* CONFIG_KVM_HYPERV */
>
> void nested_sync_vmcs12_to_shadow(struct kvm_vcpu *vcpu)
> {
> @@ -3155,6 +3162,7 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
> return 0;
> }
>
> +#ifdef CONFIG_KVM_HYPERV
> static bool nested_get_evmcs_page(struct kvm_vcpu *vcpu)
> {
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> @@ -3182,6 +3190,9 @@ static bool nested_get_evmcs_page(struct kvm_vcpu *vcpu)
>
> return true;
> }
> +#else
> +static bool nested_get_evmcs_page(struct kvm_vcpu *vcpu) { return true; }
> +#endif
>
> static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
> {
> @@ -3552,11 +3563,13 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
> if (!nested_vmx_check_permission(vcpu))
> return 1;
>
> +#ifdef CONFIG_KVM_HYPERV
> evmptrld_status = nested_vmx_handle_enlightened_vmptrld(vcpu, launch);
> if (evmptrld_status == EVMPTRLD_ERROR) {
> kvm_queue_exception(vcpu, UD_VECTOR);
> return 1;
> }
> +#endif
>
> kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
>
> @@ -7090,7 +7103,9 @@ struct kvm_x86_nested_ops vmx_nested_ops = {
> .set_state = vmx_set_nested_state,
> .get_nested_state_pages = vmx_get_nested_state_pages,
> .write_log_dirty = nested_vmx_write_pml_buffer,
> +#ifdef CONFIG_KVM_HYPERV
> .enable_evmcs = nested_enable_evmcs,
> .get_evmcs_version = nested_get_evmcs_version,
> .hv_inject_synthetic_vmexit_post_tlb_flush = vmx_hv_inject_synthetic_vmexit_post_tlb_flush,
> +#endif
> };
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index cc2524598368..8ef9898092cd 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1504,6 +1504,8 @@ static unsigned num_msrs_to_save;
> static const u32 emulated_msrs_all[] = {
> MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
> MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
> +
> +#ifdef CONFIG_KVM_HYPERV
> HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
> HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
> HV_X64_MSR_TSC_FREQUENCY, HV_X64_MSR_APIC_FREQUENCY,
> @@ -1521,6 +1523,7 @@ static const u32 emulated_msrs_all[] = {
> HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
> HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
> HV_X64_MSR_SYNDBG_PENDING_BUFFER,
> +#endif
>
> MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
> MSR_KVM_PV_EOI_EN, MSR_KVM_ASYNC_PF_INT, MSR_KVM_ASYNC_PF_ACK,
> @@ -4022,6 +4025,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> * the need to ignore the workaround.
> */
> break;
> +#ifdef CONFIG_KVM_HYPERV
> case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
> case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
> case HV_X64_MSR_SYNDBG_OPTIONS:
> @@ -4034,6 +4038,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> case HV_X64_MSR_TSC_INVARIANT_CONTROL:
> return kvm_hv_set_msr_common(vcpu, msr, data,
> msr_info->host_initiated);
> +#endif
> case MSR_IA32_BBL_CR_CTL3:
> /* Drop writes to this legacy MSR -- see rdmsr
> * counterpart for further detail.
> @@ -4378,6 +4383,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> */
> msr_info->data = 0x20000000;
> break;
> +#ifdef CONFIG_KVM_HYPERV
> case HV_X64_MSR_GUEST_OS_ID ... HV_X64_MSR_SINT15:
> case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
> case HV_X64_MSR_SYNDBG_OPTIONS:
> @@ -4391,6 +4397,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return kvm_hv_get_msr_common(vcpu,
> msr_info->index, &msr_info->data,
> msr_info->host_initiated);
> +#endif
> case MSR_IA32_BBL_CR_CTL3:
> /* This legacy MSR exists but isn't fully documented in current
> * silicon. It is however accessed by winxp in very narrow
> @@ -4528,6 +4535,7 @@ static inline bool kvm_can_mwait_in_guest(void)
> boot_cpu_has(X86_FEATURE_ARAT);
> }
>
> +#ifdef CONFIG_KVM_HYPERV
> static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu,
> struct kvm_cpuid2 __user *cpuid_arg)
> {
> @@ -4548,6 +4556,7 @@ static int kvm_ioctl_get_supported_hv_cpuid(struct kvm_vcpu *vcpu,
>
> return 0;
> }
> +#endif
>
> int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> {
> @@ -4574,9 +4583,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> case KVM_CAP_PIT_STATE2:
> case KVM_CAP_SET_IDENTITY_MAP_ADDR:
> case KVM_CAP_VCPU_EVENTS:
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_CAP_HYPERV:
> case KVM_CAP_HYPERV_VAPIC:
> case KVM_CAP_HYPERV_SPIN:
> + case KVM_CAP_HYPERV_TIME:
> case KVM_CAP_HYPERV_SYNIC:
> case KVM_CAP_HYPERV_SYNIC2:
> case KVM_CAP_HYPERV_VP_INDEX:
> @@ -4586,6 +4597,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> case KVM_CAP_HYPERV_CPUID:
> case KVM_CAP_HYPERV_ENFORCE_CPUID:
> case KVM_CAP_SYS_HYPERV_CPUID:
> +#endif
> case KVM_CAP_PCI_SEGMENT:
> case KVM_CAP_DEBUGREGS:
> case KVM_CAP_X86_ROBUST_SINGLESTEP:
> @@ -4595,7 +4607,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> case KVM_CAP_GET_TSC_KHZ:
> case KVM_CAP_KVMCLOCK_CTRL:
> case KVM_CAP_READONLY_MEM:
> - case KVM_CAP_HYPERV_TIME:
> case KVM_CAP_IOAPIC_POLARITY_IGNORED:
> case KVM_CAP_TSC_DEADLINE_TIMER:
> case KVM_CAP_DISABLE_QUIRKS:
> @@ -4705,12 +4716,14 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> r = kvm_x86_ops.nested_ops->get_state ?
> kvm_x86_ops.nested_ops->get_state(NULL, NULL, 0) : 0;
> break;
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_CAP_HYPERV_DIRECT_TLBFLUSH:
> r = kvm_x86_ops.enable_l2_tlb_flush != NULL;
> break;
> case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
> r = kvm_x86_ops.nested_ops->enable_evmcs != NULL;
> break;
> +#endif
> case KVM_CAP_SMALLER_MAXPHYADDR:
> r = (int) allow_smaller_maxphyaddr;
> break;
> @@ -4872,9 +4885,11 @@ long kvm_arch_dev_ioctl(struct file *filp,
> case KVM_GET_MSRS:
> r = msr_io(NULL, argp, do_get_msr_feature, 1);
> break;
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_GET_SUPPORTED_HV_CPUID:
> r = kvm_ioctl_get_supported_hv_cpuid(NULL, argp);
> break;
> +#endif
> case KVM_GET_DEVICE_ATTR: {
> struct kvm_device_attr attr;
> r = -EFAULT;
> @@ -5700,14 +5715,11 @@ static int kvm_vcpu_ioctl_device_attr(struct kvm_vcpu *vcpu,
> static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
> struct kvm_enable_cap *cap)
> {
> - int r;
> - uint16_t vmcs_version;
> - void __user *user_ptr;
> -
> if (cap->flags)
> return -EINVAL;
>
> switch (cap->cap) {
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_CAP_HYPERV_SYNIC2:
> if (cap->args[0])
> return -EINVAL;
> @@ -5719,16 +5731,22 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
> return kvm_hv_activate_synic(vcpu, cap->cap ==
> KVM_CAP_HYPERV_SYNIC2);
> case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
> - if (!kvm_x86_ops.nested_ops->enable_evmcs)
> - return -ENOTTY;
> - r = kvm_x86_ops.nested_ops->enable_evmcs(vcpu, &vmcs_version);
> - if (!r) {
> - user_ptr = (void __user *)(uintptr_t)cap->args[0];
> - if (copy_to_user(user_ptr, &vmcs_version,
> - sizeof(vmcs_version)))
> - r = -EFAULT;
> + {
> + int r;
> + uint16_t vmcs_version;
> + void __user *user_ptr;
> +
> + if (!kvm_x86_ops.nested_ops->enable_evmcs)
> + return -ENOTTY;
> + r = kvm_x86_ops.nested_ops->enable_evmcs(vcpu, &vmcs_version);
> + if (!r) {
> + user_ptr = (void __user *)(uintptr_t)cap->args[0];
> + if (copy_to_user(user_ptr, &vmcs_version,
> + sizeof(vmcs_version)))
> + r = -EFAULT;
> + }
> + return r;
> }
> - return r;

Minor nitpick: Unless I missed something the above is just refactoring. Can this be split
into a separate patch?


> case KVM_CAP_HYPERV_DIRECT_TLBFLUSH:
> if (!kvm_x86_ops.enable_l2_tlb_flush)
> return -ENOTTY;
> @@ -5737,6 +5755,7 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
>
> case KVM_CAP_HYPERV_ENFORCE_CPUID:
> return kvm_hv_set_enforce_cpuid(vcpu, cap->args[0]);
> +#endif
>
> case KVM_CAP_ENFORCE_PV_FEATURE_CPUID:
> vcpu->arch.pv_cpuid.enforce = cap->args[0];
> @@ -6129,9 +6148,11 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
> srcu_read_unlock(&vcpu->kvm->srcu, idx);
> break;
> }
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_GET_SUPPORTED_HV_CPUID:
> r = kvm_ioctl_get_supported_hv_cpuid(vcpu, argp);
> break;
> +#endif
> #ifdef CONFIG_KVM_XEN
> case KVM_XEN_VCPU_GET_ATTR: {
> struct kvm_xen_vcpu_attr xva;
> @@ -7189,6 +7210,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
> r = static_call(kvm_x86_mem_enc_unregister_region)(kvm, &region);
> break;
> }
> +#ifdef CONFIG_KVM_HYPERV
> case KVM_HYPERV_EVENTFD: {
> struct kvm_hyperv_eventfd hvevfd;
>
> @@ -7198,6 +7220,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
> r = kvm_vm_ioctl_hv_eventfd(kvm, &hvevfd);
> break;
> }
> +#endif
> case KVM_SET_PMU_EVENT_FILTER:
> r = kvm_vm_ioctl_set_pmu_event_filter(kvm, argp);
> break;
> @@ -10576,19 +10599,20 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
>
> static void vcpu_load_eoi_exitmap(struct kvm_vcpu *vcpu)
> {
> - u64 eoi_exit_bitmap[4];
> -
> if (!kvm_apic_hw_enabled(vcpu->arch.apic))
> return;
>
> +#ifdef CONFIG_KVM_HYPERV
> if (to_hv_vcpu(vcpu)) {
> + u64 eoi_exit_bitmap[4];
> +
> bitmap_or((ulong *)eoi_exit_bitmap,
> vcpu->arch.ioapic_handled_vectors,
> to_hv_synic(vcpu)->vec_bitmap, 256);
> static_call_cond(kvm_x86_load_eoi_exitmap)(vcpu, eoi_exit_bitmap);
> return;
> }
> -
> +#endif

Same here.

> static_call_cond(kvm_x86_load_eoi_exitmap)(
> vcpu, (u64 *)vcpu->arch.ioapic_handled_vectors);
> }
> @@ -10679,9 +10703,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> * the flushes are considered "remote" and not "local" because
> * the requests can be initiated from other vCPUs.
> */
> +#ifdef CONFIG_KVM_HYPERV
> if (kvm_check_request(KVM_REQ_HV_TLB_FLUSH, vcpu) &&
> kvm_hv_vcpu_flush_tlb(vcpu))
> kvm_vcpu_flush_tlb_guest(vcpu);
> +#endif
>
> if (kvm_check_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu)) {
> vcpu->run->exit_reason = KVM_EXIT_TPR_ACCESS;
> @@ -10734,6 +10760,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> vcpu_load_eoi_exitmap(vcpu);
> if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
> kvm_vcpu_reload_apic_access_page(vcpu);
> +#ifdef CONFIG_KVM_HYPERV
> if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) {
> vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> vcpu->run->system_event.type = KVM_SYSTEM_EVENT_CRASH;
> @@ -10764,6 +10791,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> */
> if (kvm_check_request(KVM_REQ_HV_STIMER, vcpu))
> kvm_hv_process_stimers(vcpu);
> +#endif
> if (kvm_check_request(KVM_REQ_APICV_UPDATE, vcpu))
> kvm_vcpu_update_apicv(vcpu);
> if (kvm_check_request(KVM_REQ_APF_READY, vcpu))

Besides nitpicks,

Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>


Best regards,
Maxim Levitsky