On Wed, Nov 3, 2021 at 5:15 PM Oliver Upton <oupton@xxxxxxxxxx> wrote: > > On Tue, Nov 02, 2021 at 12:21:58AM +0000, Raghavendra Rao Ananta wrote: > > Introduce a firmware register that encapsulates standard secure > > service calls (owner value 4) as a bitmap. Depending on how the > > user-space configures the register, the features will be enabled > > or disabled for the guest. Currently, this includes support only > > for ARM True Random Number Generator (TRNG) service, with bit-0 > > of the register representing mandatory features of v1.0. > > > > Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx> > > --- > > Documentation/virt/kvm/arm/hypercalls.rst | 17 +++++ > > arch/arm64/include/asm/kvm_host.h | 2 + > > arch/arm64/include/uapi/asm/kvm.h | 6 ++ > > arch/arm64/kvm/arm.c | 8 +++ > > arch/arm64/kvm/hypercalls.c | 75 ++++++++++++++++++++++- > > arch/arm64/kvm/trng.c | 9 +-- > > include/kvm/arm_hypercalls.h | 5 ++ > > 7 files changed, 113 insertions(+), 9 deletions(-) > > > > diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst > > index 85dfd682d811..1601919f256d 100644 > > --- a/Documentation/virt/kvm/arm/hypercalls.rst > > +++ b/Documentation/virt/kvm/arm/hypercalls.rst > > @@ -20,6 +20,14 @@ pseudo-registers" that can be manipulated using the GET/SET_ONE_REG > > interface. These registers can be saved/restored by userspace, and set > > to a convenient value if required. > > > > +The firmware register KVM_REG_ARM_STD exposes the hypercall services > > nit: try to cram BITMAP in the name. IMO, this will help disambiguate > with version-based FW regs, like KVM_REG_ARM_PSCI_VERSION. > > > +in the form of a feature bitmap. Upon VM creation, by default, KVM exposes > > +all the features to the guest, which can be learnt using GET_ONE_REG > > +interface. Conversely, the features can be enabled or disabled via the > > +SET_ONE_REG interface. These registers allow the user-space modification > > +only until the VM has started running, after which they turn to read-only > > +registers. SET_ONE_REG in this scenario will return -EBUSY. > > + > > The following register is defined: > > > > * KVM_REG_ARM_PSCI_VERSION: > > @@ -74,4 +82,13 @@ The following register is defined: > > KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED: > > The workaround is always active on this vCPU or it is not needed. > > > > +* KVM_REG_ARM_STD: > > + Controls the bitmap of the ARM Standard Secure Service Calls. > > + > > + The following bits are accepted: > > + > > + KVM_REG_ARM_STD_TRNG_V1_0: > > state the bit position as well > I was afraid of the name getting too long. But let me see. > > + The bit represents the services offered under v1.0 of ARM True Random Number Generator > > + (TRNG) specification (ARM DEN 0098). > > + > > .. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > > index 0b2502494a17..176d6be7b4da 100644 > > --- a/arch/arm64/include/asm/kvm_host.h > > +++ b/arch/arm64/include/asm/kvm_host.h > > @@ -105,6 +105,8 @@ struct kvm_arch_memory_slot { > > struct hvc_reg_desc { > > bool write_disabled; > > bool write_attempted; > > + > > + u64 kvm_std_bmap; > > }; > > > > struct kvm_arch { > > diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h > > index b3edde68bc3e..6387dea5396d 100644 > > --- a/arch/arm64/include/uapi/asm/kvm.h > > +++ b/arch/arm64/include/uapi/asm/kvm.h > > @@ -281,6 +281,12 @@ struct kvm_arm_copy_mte_tags { > > #define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED 3 > > #define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4) > > > > +#define KVM_REG_ARM_STD KVM_REG_ARM_FW_REG(3) > > +enum kvm_reg_arm_std_bmap { > > + KVM_REG_ARM_STD_TRNG_V1_0, > > + KVM_REG_ARM_STD_BMAP_MAX, > > +}; > > + > > I would recommend just defining the bit values explicitly rather than > using an enumeration: > > #define KVM_REG_ARM_STD_TRNG_V1_0 (1ULL << 0) > > You do lose the convenience of having KVM_REG_ARM_STD_BMAP_MAX. > Just curious, any particular reason for this? IMO, going an enum route could avoid human errors. Anything I'm missing? > > /* SVE registers */ > > #define KVM_REG_ARM64_SVE (0x15 << KVM_REG_ARM_COPROC_SHIFT) > > > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > > index f9a25e439e99..1cf58aa49222 100644 > > --- a/arch/arm64/kvm/arm.c > > +++ b/arch/arm64/kvm/arm.c > > @@ -130,6 +130,13 @@ static void set_default_spectre(struct kvm *kvm) > > kvm->arch.pfr0_csv3 = 1; > > } > > > > +static void set_default_hypercalls(struct kvm *kvm) > > +{ > > + struct hvc_reg_desc *hvc_desc = &kvm->arch.hvc_desc; > > + > > + hvc_desc->kvm_std_bmap = ARM_SMCCC_STD_FEATURES; > > +} > > + > > /** > > * kvm_arch_init_vm - initializes a VM data structure > > * @kvm: pointer to the KVM struct > > @@ -156,6 +163,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > > kvm->arch.max_vcpus = kvm_arm_default_max_vcpus(); > > > > set_default_spectre(kvm); > > + set_default_hypercalls(kvm); > > > > return ret; > > out_free_stage2_pgd: > > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > > index 7e873206a05b..0b3006353bf6 100644 > > --- a/arch/arm64/kvm/hypercalls.c > > +++ b/arch/arm64/kvm/hypercalls.c > > @@ -60,8 +60,64 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val) > > > > static u64 *kvm_fw_reg_to_bmap(struct kvm *kvm, u64 fw_reg) > > { > > - /* No firmware registers supporting hvc bitmaps exits yet */ > > - return NULL; > > + struct hvc_reg_desc *hvc_desc = &kvm->arch.hvc_desc; > > + > > + switch (fw_reg) { > > + case KVM_REG_ARM_STD: > > + return &hvc_desc->kvm_std_bmap; > > + default: > > + return NULL; > > + } > > +} > > + > > +struct kvm_hvc_func_map { > > + u32 func_id; > > + u64 bmap_bit; > > +}; > > + > > +#define HVC_FUNC_MAP_DESC(func, bit) \ > > + { \ > > + .func_id = func, \ > > + .bmap_bit = bit, \ > > + } > > + > > +static const struct kvm_hvc_func_map hvc_std_map[] = { > > + HVC_FUNC_MAP_DESC(ARM_SMCCC_TRNG_GET_UUID, KVM_REG_ARM_STD_TRNG_V1_0), > > + HVC_FUNC_MAP_DESC(ARM_SMCCC_TRNG_RND32, KVM_REG_ARM_STD_TRNG_V1_0), > > + HVC_FUNC_MAP_DESC(ARM_SMCCC_TRNG_RND64, KVM_REG_ARM_STD_TRNG_V1_0), > > +}; > > + > > +bool kvm_hvc_call_supported(struct kvm_vcpu *vcpu, u32 func_id) > > +{ > > + struct kvm *kvm = vcpu->kvm; > > + u8 hvc_owner = ARM_SMCCC_OWNER_NUM(func_id); > > + const struct kvm_hvc_func_map *hvc_func_map = NULL; > > + > > + u64 fw_reg, *hc_bmap; > > + unsigned int map_sz, i; > > + > > + switch (hvc_owner) { > > + case ARM_SMCCC_OWNER_STANDARD: > > + fw_reg = KVM_REG_ARM_STD; > > + hvc_func_map = hvc_std_map; > > + map_sz = ARRAY_SIZE(hvc_std_map); > > + break; > > + default: > > + /* Allow all the owners that aren't mapped */ > > + return true; > > + } > > + > > + hc_bmap = kvm_fw_reg_to_bmap(kvm, fw_reg); > > + if (!hc_bmap) > > + return true; > > + > > + for (i = 0; i < map_sz; i++) { > > + if (func_id == hvc_func_map[i].func_id) > > + return *hc_bmap & BIT(hvc_func_map[i].bmap_bit); > > + } > > Hrm... > > Could you instead define a helper function for each service and use a > switch statement to ensure each function tests the correct bit? This > would avoid the need to loop over a map. > I think so.. I guess I was trying to avoid making too many changes if we want to support a new func_id. > > + > > + /* Allow all the functions of an owner that aren't mapped */ > > + return true; > > } > > > > int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) > > @@ -71,6 +127,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) > > u32 feature; > > gpa_t gpa; > > > > + if (!kvm_hvc_call_supported(vcpu, func_id)) > > + goto out; > > + > > switch (func_id) { > > case ARM_SMCCC_VERSION_FUNC_ID: > > val[0] = ARM_SMCCC_VERSION_1_1; > > @@ -149,6 +208,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) > > return kvm_psci_call(vcpu); > > } > > > > +out: > > smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]); > > return 1; > > } > > @@ -157,6 +217,7 @@ static const u64 fw_reg_ids[] = { > > KVM_REG_ARM_PSCI_VERSION, > > KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, > > KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, > > + KVM_REG_ARM_STD, > > This (and all other FW regs you add) need to be added to the > get-reg-list selftest. Marc/Andrew have reminded me enough times to do > this myself, so I'll share suggestion :-P > Yes, of course. It's on my todo list. I'll try to include that in the next patchset. > > }; > > > > int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu) > > @@ -219,6 +280,7 @@ static int get_kernel_wa_level(u64 regid) > > > > int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) > > { > > + struct hvc_reg_desc *hvc_desc = &vcpu->kvm->arch.hvc_desc; > > void __user *uaddr = (void __user *)(long)reg->addr; > > u64 val; > > > > @@ -230,6 +292,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) > > case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: > > val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK; > > break; > > + case KVM_REG_ARM_STD: > > + val = hvc_desc->kvm_std_bmap; > > + break; > > default: > > return -ENOENT; > > } > > @@ -352,6 +417,12 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) > > if (get_kernel_wa_level(reg->id) < wa_level) > > return -EINVAL; > > > > + return 0; > > + case KVM_REG_ARM_STD: > > + if (val & ~ARM_SMCCC_STD_FEATURES) > > + return -EINVAL; > > + > > + hvc_desc->kvm_std_bmap = val; > > return 0; > > default: > > return -ENOENT; > > diff --git a/arch/arm64/kvm/trng.c b/arch/arm64/kvm/trng.c > > index 99bdd7103c9c..6dff765f5b9b 100644 > > --- a/arch/arm64/kvm/trng.c > > +++ b/arch/arm64/kvm/trng.c > > @@ -60,14 +60,9 @@ int kvm_trng_call(struct kvm_vcpu *vcpu) > > val = ARM_SMCCC_TRNG_VERSION_1_0; > > break; > > case ARM_SMCCC_TRNG_FEATURES: > > - switch (smccc_get_arg1(vcpu)) { > > - case ARM_SMCCC_TRNG_VERSION: > > - case ARM_SMCCC_TRNG_FEATURES: > > - case ARM_SMCCC_TRNG_GET_UUID: > > - case ARM_SMCCC_TRNG_RND32: > > - case ARM_SMCCC_TRNG_RND64: > > + if (kvm_hvc_call_supported(vcpu, smccc_get_arg1(vcpu))) > > val = TRNG_SUCCESS; > > - } > > + > > break; > > case ARM_SMCCC_TRNG_GET_UUID: > > smccc_set_retval(vcpu, le32_to_cpu(u[0]), le32_to_cpu(u[1]), > > diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h > > index 5d38628a8d04..5f01bb139312 100644 > > --- a/include/kvm/arm_hypercalls.h > > +++ b/include/kvm/arm_hypercalls.h > > @@ -6,6 +6,9 @@ > > > > #include <asm/kvm_emulate.h> > > > > +#define ARM_SMCCC_STD_FEATURES \ > > + GENMASK_ULL(KVM_REG_ARM_STD_BMAP_MAX - 1, 0) > > + > > int kvm_hvc_call_handler(struct kvm_vcpu *vcpu); > > > > static inline u32 smccc_get_function(struct kvm_vcpu *vcpu) > > @@ -47,4 +50,6 @@ int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices); > > int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg); > > int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg); > > > > +bool kvm_hvc_call_supported(struct kvm_vcpu *vcpu, u32 func_id); > > + > > #endif > > -- > > 2.33.1.1089.g2158813163f-goog > > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
