| Message ID | 20231025152406.1879274-3-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Make Hyper-V emulation optional | expand |
On Wed, 2023-10-25 at 17:23 +0200, Vitaly Kuznetsov wrote: > Hyper-V partition assist page is used when KVM runs on top of Hyper-V and > is not used for Windows/Hyper-V guests on KVM, this means that 'hv_pa_pg' > placement in 'struct kvm_hv' is unfortunate. As a preparation to making > Hyper-V emulation optional, move 'hv_pa_pg' to 'struct kvm_arch' and put it > under CONFIG_HYPERV. > > While on it, introduce hv_get_partition_assist_page() helper to allocate > partition assist page. Move the comment explaining why we use a single page > for all vCPUs from VMX and expand it a bit. > > No functional change intended. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > --- > arch/x86/include/asm/kvm_host.h | 2 +- > arch/x86/kvm/kvm_onhyperv.h | 20 ++++++++++++++++++++ > arch/x86/kvm/svm/svm_onhyperv.c | 10 +++------- > arch/x86/kvm/vmx/vmx.c | 14 +++----------- > arch/x86/kvm/x86.c | 4 +++- > 5 files changed, 30 insertions(+), 20 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index d107516b4591..7fb2810f4573 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1125,7 +1125,6 @@ struct kvm_hv { > */ > unsigned int synic_auto_eoi_used; > > - struct hv_partition_assist_pg *hv_pa_pg; > struct kvm_hv_syndbg hv_syndbg; > }; > > @@ -1447,6 +1446,7 @@ struct kvm_arch { > #if IS_ENABLED(CONFIG_HYPERV) > hpa_t hv_root_tdp; > spinlock_t hv_root_tdp_lock; > + struct hv_partition_assist_pg *hv_pa_pg; > #endif > /* > * VM-scope maximum vCPU ID. Used to determine the size of structures > diff --git a/arch/x86/kvm/kvm_onhyperv.h b/arch/x86/kvm/kvm_onhyperv.h > index f9ca3e7432b2..eefab3dc8498 100644 > --- a/arch/x86/kvm/kvm_onhyperv.h > +++ b/arch/x86/kvm/kvm_onhyperv.h > @@ -10,6 +10,26 @@ > int hv_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, gfn_t nr_pages); > int hv_flush_remote_tlbs(struct kvm *kvm); > void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp); > +static inline hpa_t hv_get_partition_assist_page(struct kvm_vcpu *vcpu) > +{ > + /* > + * Partition assist page is something which Hyper-V running in L0 > + * requires from KVM running in L1 before direct TLB flush for L2 > + * guests can be enabled. KVM doesn't currently use the page but to > + * comply with TLFS it still needs to be allocated. For now, this > + * is a single page shared among all vCPUs. Perfect! > + */ > + struct hv_partition_assist_pg **p_hv_pa_pg = > + &vcpu->kvm->arch.hv_pa_pg; > + > + if (!*p_hv_pa_pg) > + *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); > + > + if (!*p_hv_pa_pg) > + return INVALID_PAGE; > + > + return __pa(*p_hv_pa_pg); > +} > #else /* !CONFIG_HYPERV */ > static inline int hv_flush_remote_tlbs(struct kvm *kvm) > { > diff --git a/arch/x86/kvm/svm/svm_onhyperv.c b/arch/x86/kvm/svm/svm_onhyperv.c > index 7af8422d3382..3971b3ea5d04 100644 > --- a/arch/x86/kvm/svm/svm_onhyperv.c > +++ b/arch/x86/kvm/svm/svm_onhyperv.c > @@ -18,18 +18,14 @@ > int svm_hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu) > { > struct hv_vmcb_enlightenments *hve; > - struct hv_partition_assist_pg **p_hv_pa_pg = > - &to_kvm_hv(vcpu->kvm)->hv_pa_pg; > + hpa_t partition_assist_page = hv_get_partition_assist_page(vcpu); > > - if (!*p_hv_pa_pg) > - *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL); > - > - if (!*p_hv_pa_pg) > + if (partition_assist_page == INVALID_PAGE) > return -ENOMEM; > > hve = &to_svm(vcpu)->vmcb->control.hv_enlightenments; > > - hve->partition_assist_page = __pa(*p_hv_pa_pg); > + hve->partition_assist_page = partition_assist_page; > hve->hv_vm_id = (unsigned long)vcpu->kvm; > if (!hve->hv_enlightenments_control.nested_flush_hypercall) { > hve->hv_enlightenments_control.nested_flush_hypercall = 1; > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index be20a60047b1..cb4591405f14 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -523,22 +523,14 @@ module_param(enlightened_vmcs, bool, 0444); > static int hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu) > { > struct hv_enlightened_vmcs *evmcs; > - struct hv_partition_assist_pg **p_hv_pa_pg = > - &to_kvm_hv(vcpu->kvm)->hv_pa_pg; > - /* > - * Synthetic VM-Exit is not enabled in current code and so All > - * evmcs in singe VM shares same assist page. > - */ > - if (!*p_hv_pa_pg) > - *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); > + hpa_t partition_assist_page = hv_get_partition_assist_page(vcpu); > > - if (!*p_hv_pa_pg) > + if (partition_assist_page == INVALID_PAGE) > return -ENOMEM; > > evmcs = (struct hv_enlightened_vmcs *)to_vmx(vcpu)->loaded_vmcs->vmcs; > > - evmcs->partition_assist_page = > - __pa(*p_hv_pa_pg); > + evmcs->partition_assist_page = partition_assist_page; > evmcs->hv_vm_id = (unsigned long)vcpu->kvm; > evmcs->hv_enlightenments_control.nested_flush_hypercall = 1; > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d632931fa545..cc2524598368 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -12425,7 +12425,9 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) > > void kvm_arch_free_vm(struct kvm *kvm) > { > - kfree(to_kvm_hv(kvm)->hv_pa_pg); > +#if IS_ENABLED(CONFIG_HYPERV) > + kfree(kvm->arch.hv_pa_pg); > +#endif > __kvm_arch_free_vm(kvm); > } > Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Best regards, Maxim Levitsky
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d107516b4591..7fb2810f4573 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1125,7 +1125,6 @@ struct kvm_hv { */ unsigned int synic_auto_eoi_used; - struct hv_partition_assist_pg *hv_pa_pg; struct kvm_hv_syndbg hv_syndbg; }; @@ -1447,6 +1446,7 @@ struct kvm_arch { #if IS_ENABLED(CONFIG_HYPERV) hpa_t hv_root_tdp; spinlock_t hv_root_tdp_lock; + struct hv_partition_assist_pg *hv_pa_pg; #endif /* * VM-scope maximum vCPU ID. Used to determine the size of structures diff --git a/arch/x86/kvm/kvm_onhyperv.h b/arch/x86/kvm/kvm_onhyperv.h index f9ca3e7432b2..eefab3dc8498 100644 --- a/arch/x86/kvm/kvm_onhyperv.h +++ b/arch/x86/kvm/kvm_onhyperv.h @@ -10,6 +10,26 @@ int hv_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, gfn_t nr_pages); int hv_flush_remote_tlbs(struct kvm *kvm); void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp); +static inline hpa_t hv_get_partition_assist_page(struct kvm_vcpu *vcpu) +{ + /* + * Partition assist page is something which Hyper-V running in L0 + * requires from KVM running in L1 before direct TLB flush for L2 + * guests can be enabled. KVM doesn't currently use the page but to + * comply with TLFS it still needs to be allocated. For now, this + * is a single page shared among all vCPUs. + */ + struct hv_partition_assist_pg **p_hv_pa_pg = + &vcpu->kvm->arch.hv_pa_pg; + + if (!*p_hv_pa_pg) + *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); + + if (!*p_hv_pa_pg) + return INVALID_PAGE; + + return __pa(*p_hv_pa_pg); +} #else /* !CONFIG_HYPERV */ static inline int hv_flush_remote_tlbs(struct kvm *kvm) { diff --git a/arch/x86/kvm/svm/svm_onhyperv.c b/arch/x86/kvm/svm/svm_onhyperv.c index 7af8422d3382..3971b3ea5d04 100644 --- a/arch/x86/kvm/svm/svm_onhyperv.c +++ b/arch/x86/kvm/svm/svm_onhyperv.c @@ -18,18 +18,14 @@ int svm_hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu) { struct hv_vmcb_enlightenments *hve; - struct hv_partition_assist_pg **p_hv_pa_pg = - &to_kvm_hv(vcpu->kvm)->hv_pa_pg; + hpa_t partition_assist_page = hv_get_partition_assist_page(vcpu); - if (!*p_hv_pa_pg) - *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL); - - if (!*p_hv_pa_pg) + if (partition_assist_page == INVALID_PAGE) return -ENOMEM; hve = &to_svm(vcpu)->vmcb->control.hv_enlightenments; - hve->partition_assist_page = __pa(*p_hv_pa_pg); + hve->partition_assist_page = partition_assist_page; hve->hv_vm_id = (unsigned long)vcpu->kvm; if (!hve->hv_enlightenments_control.nested_flush_hypercall) { hve->hv_enlightenments_control.nested_flush_hypercall = 1; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index be20a60047b1..cb4591405f14 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -523,22 +523,14 @@ module_param(enlightened_vmcs, bool, 0444); static int hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu) { struct hv_enlightened_vmcs *evmcs; - struct hv_partition_assist_pg **p_hv_pa_pg = - &to_kvm_hv(vcpu->kvm)->hv_pa_pg; - /* - * Synthetic VM-Exit is not enabled in current code and so All - * evmcs in singe VM shares same assist page. - */ - if (!*p_hv_pa_pg) - *p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); + hpa_t partition_assist_page = hv_get_partition_assist_page(vcpu); - if (!*p_hv_pa_pg) + if (partition_assist_page == INVALID_PAGE) return -ENOMEM; evmcs = (struct hv_enlightened_vmcs *)to_vmx(vcpu)->loaded_vmcs->vmcs; - evmcs->partition_assist_page = - __pa(*p_hv_pa_pg); + evmcs->partition_assist_page = partition_assist_page; evmcs->hv_vm_id = (unsigned long)vcpu->kvm; evmcs->hv_enlightenments_control.nested_flush_hypercall = 1; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d632931fa545..cc2524598368 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12425,7 +12425,9 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) void kvm_arch_free_vm(struct kvm *kvm) { - kfree(to_kvm_hv(kvm)->hv_pa_pg); +#if IS_ENABLED(CONFIG_HYPERV) + kfree(kvm->arch.hv_pa_pg); +#endif __kvm_arch_free_vm(kvm); }
Hyper-V partition assist page is used when KVM runs on top of Hyper-V and is not used for Windows/Hyper-V guests on KVM, this means that 'hv_pa_pg' placement in 'struct kvm_hv' is unfortunate. As a preparation to making Hyper-V emulation optional, move 'hv_pa_pg' to 'struct kvm_arch' and put it under CONFIG_HYPERV. While on it, introduce hv_get_partition_assist_page() helper to allocate partition assist page. Move the comment explaining why we use a single page for all vCPUs from VMX and expand it a bit. No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/kvm_onhyperv.h | 20 ++++++++++++++++++++ arch/x86/kvm/svm/svm_onhyperv.c | 10 +++------- arch/x86/kvm/vmx/vmx.c | 14 +++----------- arch/x86/kvm/x86.c | 4 +++- 5 files changed, 30 insertions(+), 20 deletions(-)