| Message ID | 20241202154742.3611749-5-tabba@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: arm64: Rework guest VM fixed feature handling and trapping in pKVM | expand |
On Monday 02 Dec 2024 at 15:47:31 (+0000), Fuad Tabba wrote: > diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c > index fb733b36c6c1..59ff6aac514c 100644 > --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c > +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c > @@ -329,34 +329,20 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc > > bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); > > - /* > - * For protected VMs, always allow: > - * - CPU starting in poweroff state > - * - PSCI v0.2 > - */ > - set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); For my understanding, why do we drop this bit? > set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed_features); > > - /* > - * Check if remaining features are allowed: > - * - Performance Monitoring > - * - Scalable Vectors > - * - Pointer Authentication > - */ > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), PVM_ID_AA64DFR0_ALLOW)) > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PMU_V3)) > set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), PVM_ID_AA64PFR0_ALLOW)) > - set_bit(KVM_ARM_VCPU_SVE, allowed_features); > - > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API), PVM_ID_AA64ISAR1_ALLOW) && > - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA), PVM_ID_AA64ISAR1_ALLOW)) > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_ADDRESS)) > set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI), PVM_ID_AA64ISAR1_ALLOW) && > - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA), PVM_ID_AA64ISAR1_ALLOW)) > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_GENERIC)) > set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); > > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_SVE)) > + set_bit(KVM_ARM_VCPU_SVE, allowed_features); > + > bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, > allowed_features, KVM_VCPU_MAX_FEATURES); > } > -- > 2.47.0.338.g60cca15819-goog >
Hi Quentin, On Fri, 6 Dec 2024 at 17:10, Quentin Perret <qperret@google.com> wrote: > > On Monday 02 Dec 2024 at 15:47:31 (+0000), Fuad Tabba wrote: > > diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > index fb733b36c6c1..59ff6aac514c 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c > > +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > @@ -329,34 +329,20 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc > > > > bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); > > > > - /* > > - * For protected VMs, always allow: > > - * - CPU starting in poweroff state > > - * - PSCI v0.2 > > - */ > > - set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); > > For my understanding, why do we drop this bit? Since the hypervisor is responsible for the power state of protected VMs. This should either be a separate patch or I should explain it in the commit message. Any preference? Thanks, /fuad > > set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed_features); > > > > - /* > > - * Check if remaining features are allowed: > > - * - Performance Monitoring > > - * - Scalable Vectors > > - * - Pointer Authentication > > - */ > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), PVM_ID_AA64DFR0_ALLOW)) > > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PMU_V3)) > > set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); > > > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), PVM_ID_AA64PFR0_ALLOW)) > > - set_bit(KVM_ARM_VCPU_SVE, allowed_features); > > - > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API), PVM_ID_AA64ISAR1_ALLOW) && > > - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA), PVM_ID_AA64ISAR1_ALLOW)) > > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_ADDRESS)) > > set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); > > > > - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI), PVM_ID_AA64ISAR1_ALLOW) && > > - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA), PVM_ID_AA64ISAR1_ALLOW)) > > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_GENERIC)) > > set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); > > > > + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_SVE)) > > + set_bit(KVM_ARM_VCPU_SVE, allowed_features); > > + > > bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, > > allowed_features, KVM_VCPU_MAX_FEATURES); > > } > > -- > > 2.47.0.338.g60cca15819-goog > > >
On Monday 09 Dec 2024 at 08:14:15 (+0000), Fuad Tabba wrote: > Hi Quentin, > > On Fri, 6 Dec 2024 at 17:10, Quentin Perret <qperret@google.com> wrote: > > > > On Monday 02 Dec 2024 at 15:47:31 (+0000), Fuad Tabba wrote: > > > diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > index fb733b36c6c1..59ff6aac514c 100644 > > > --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > @@ -329,34 +329,20 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc > > > > > > bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); > > > > > > - /* > > > - * For protected VMs, always allow: > > > - * - CPU starting in poweroff state > > > - * - PSCI v0.2 > > > - */ > > > - set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); > > > > For my understanding, why do we drop this bit? > > Since the hypervisor is responsible for the power state of protected > VMs. This should either be a separate patch or I should explain it in > the commit message. Any preference? Gotcha, perhaps make that its own patch so we have a commit message motivating the change?
On Wed, 11 Dec 2024 at 13:29, Quentin Perret <qperret@google.com> wrote: > > On Monday 09 Dec 2024 at 08:14:15 (+0000), Fuad Tabba wrote: > > Hi Quentin, > > > > On Fri, 6 Dec 2024 at 17:10, Quentin Perret <qperret@google.com> wrote: > > > > > > On Monday 02 Dec 2024 at 15:47:31 (+0000), Fuad Tabba wrote: > > > > diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > > index fb733b36c6c1..59ff6aac514c 100644 > > > > --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > > +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > > @@ -329,34 +329,20 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc > > > > > > > > bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); > > > > > > > > - /* > > > > - * For protected VMs, always allow: > > > > - * - CPU starting in poweroff state > > > > - * - PSCI v0.2 > > > > - */ > > > > - set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); > > > > > > For my understanding, why do we drop this bit? > > > > Since the hypervisor is responsible for the power state of protected > > VMs. This should either be a separate patch or I should explain it in > > the commit message. Any preference? > > Gotcha, perhaps make that its own patch so we have a commit message > motivating the change? Will do. /fuad
diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index cd56acd9a842..400f7cef1e81 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -20,6 +20,31 @@ int pkvm_init_host_vm(struct kvm *kvm); int pkvm_create_hyp_vm(struct kvm *kvm); void pkvm_destroy_hyp_vm(struct kvm *kvm); +/* + * This functions as an allow-list of protected VM capabilities. + * Features not explicitly allowed by this function are denied. + */ +static inline bool kvm_pvm_ext_allowed(long ext) +{ + switch (ext) { + case KVM_CAP_IRQCHIP: + case KVM_CAP_ARM_PSCI: + case KVM_CAP_ARM_PSCI_0_2: + case KVM_CAP_NR_VCPUS: + case KVM_CAP_MAX_VCPUS: + case KVM_CAP_MAX_VCPU_ID: + case KVM_CAP_MSI_DEVID: + case KVM_CAP_ARM_VM_IPA_SIZE: + case KVM_CAP_ARM_PMU_V3: + case KVM_CAP_ARM_SVE: + case KVM_CAP_ARM_PTRAUTH_ADDRESS: + case KVM_CAP_ARM_PTRAUTH_GENERIC: + return true; + default: + return false; + } +} + extern struct memblock_region kvm_nvhe_sym(hyp_memory)[]; extern unsigned int kvm_nvhe_sym(hyp_memblock_nr); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index a102c3aebdbc..b295218cdc24 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -80,31 +80,6 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; } -/* - * This functions as an allow-list of protected VM capabilities. - * Features not explicitly allowed by this function are denied. - */ -static bool pkvm_ext_allowed(struct kvm *kvm, long ext) -{ - switch (ext) { - case KVM_CAP_IRQCHIP: - case KVM_CAP_ARM_PSCI: - case KVM_CAP_ARM_PSCI_0_2: - case KVM_CAP_NR_VCPUS: - case KVM_CAP_MAX_VCPUS: - case KVM_CAP_MAX_VCPU_ID: - case KVM_CAP_MSI_DEVID: - case KVM_CAP_ARM_VM_IPA_SIZE: - case KVM_CAP_ARM_PMU_V3: - case KVM_CAP_ARM_SVE: - case KVM_CAP_ARM_PTRAUTH_ADDRESS: - case KVM_CAP_ARM_PTRAUTH_GENERIC: - return true; - default: - return false; - } -} - int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) { @@ -113,7 +88,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->flags) return -EINVAL; - if (kvm_vm_is_protected(kvm) && !pkvm_ext_allowed(kvm, cap->cap)) + if (kvm_vm_is_protected(kvm) && !kvm_pvm_ext_allowed(cap->cap)) return -EINVAL; switch (cap->cap) { @@ -311,7 +286,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r; - if (kvm && kvm_vm_is_protected(kvm) && !pkvm_ext_allowed(kvm, ext)) + if (kvm && kvm_vm_is_protected(kvm) && !kvm_pvm_ext_allowed(ext)) return 0; switch (ext) { diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index fb733b36c6c1..59ff6aac514c 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -329,34 +329,20 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); - /* - * For protected VMs, always allow: - * - CPU starting in poweroff state - * - PSCI v0.2 - */ - set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed_features); - /* - * Check if remaining features are allowed: - * - Performance Monitoring - * - Scalable Vectors - * - Pointer Authentication - */ - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), PVM_ID_AA64DFR0_ALLOW)) + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PMU_V3)) set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), PVM_ID_AA64PFR0_ALLOW)) - set_bit(KVM_ARM_VCPU_SVE, allowed_features); - - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API), PVM_ID_AA64ISAR1_ALLOW) && - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA), PVM_ID_AA64ISAR1_ALLOW)) + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_ADDRESS)) set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); - if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI), PVM_ID_AA64ISAR1_ALLOW) && - FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA), PVM_ID_AA64ISAR1_ALLOW)) + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_PTRAUTH_GENERIC)) set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); + if (kvm_pvm_ext_allowed(KVM_CAP_ARM_SVE)) + set_bit(KVM_ARM_VCPU_SVE, allowed_features); + bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, allowed_features, KVM_VCPU_MAX_FEATURES); }
Use KVM extension checks as the source for determining which capabilities are allowed for protected VMs. KVM extension checks is the natural place for this, since it is also the interface exposed to users. Signed-off-by: Fuad Tabba <tabba@google.com> --- arch/arm64/include/asm/kvm_pkvm.h | 25 +++++++++++++++++++++++++ arch/arm64/kvm/arm.c | 29 ++--------------------------- arch/arm64/kvm/hyp/nvhe/pkvm.c | 26 ++++++-------------------- 3 files changed, 33 insertions(+), 47 deletions(-)