Marc, James, Julien, Suzuki, argh, I am sorry, I forgot to CC: you guys on this patch. This is v2 of Ard's original patch, fixing the endianess problem pointed out by Drew. It's on the kvm-arm ML: https://lists.cs.columbia.edu/pipermail/kvmarm/2020-November/043138.html or here in my repo: https://gitlab.arm.com/linux-arm/linux-ap/-/commits/smccc-trng/v2/ Apologies! Cheers, Andre On 05/11/2020 12:56, Andre Przywara wrote: > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > > Provide a hypervisor implementation of the ARM architected TRNG firmware > interface described in ARM spec DEN0098. All function IDs are implemented, > including both 32-bit and 64-bit versions of the TRNG_RND service, which > is the centerpiece of the API. > > The API is backed by arch_get_unsigned_seed_long(), which is implemented > in terms of RNDRRS currently, and will be alternatively backed by a SMC > call to the secure firmware using same interface after a future patch. > If neither are available, the kernel's entropy pool is used instead. > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> > --- > arch/arm64/include/asm/kvm_host.h | 2 + > arch/arm64/kvm/Makefile | 2 +- > arch/arm64/kvm/hypercalls.c | 6 ++ > arch/arm64/kvm/trng.c | 91 +++++++++++++++++++++++++++++++ > 4 files changed, 100 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/kvm/trng.c > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 781d029b8aa8..615932bacf76 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -652,4 +652,6 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); > #define kvm_arm_vcpu_sve_finalized(vcpu) \ > ((vcpu)->arch.flags & KVM_ARM64_VCPU_SVE_FINALIZED) > > +int kvm_trng_call(struct kvm_vcpu *vcpu); > + > #endif /* __ARM64_KVM_HOST_H__ */ > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 1504c81fbf5d..a510037e3270 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -16,7 +16,7 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \ > inject_fault.o regmap.o va_layout.o handle_exit.o \ > guest.o debug.o reset.o sys_regs.o \ > vgic-sys-reg-v3.o fpsimd.o pmu.o \ > - aarch32.o arch_timer.o \ > + aarch32.o arch_timer.o trng.o \ > vgic/vgic.o vgic/vgic-init.o \ > vgic/vgic-irqfd.o vgic/vgic-v2.o \ > vgic/vgic-v3.o vgic/vgic-v4.o \ > diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c > index 25ea4ecb6449..ead21b98b620 100644 > --- a/arch/arm64/kvm/hypercalls.c > +++ b/arch/arm64/kvm/hypercalls.c > @@ -71,6 +71,12 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) > if (gpa != GPA_INVALID) > val = gpa; > break; > + 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: > + return kvm_trng_call(vcpu); > default: > return kvm_psci_call(vcpu); > } > diff --git a/arch/arm64/kvm/trng.c b/arch/arm64/kvm/trng.c > new file mode 100644 > index 000000000000..5a27b2d99977 > --- /dev/null > +++ b/arch/arm64/kvm/trng.c > @@ -0,0 +1,91 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2020 Arm Ltd. > + > +#include <linux/arm-smccc.h> > +#include <linux/kvm_host.h> > + > +#include <asm/kvm_emulate.h> > + > +#include <kvm/arm_hypercalls.h> > + > +#define ARM_SMCCC_TRNG_VERSION_1_0 0x10000UL > + > +#define TRNG_SUCCESS 0UL > +#define TRNG_NOT_SUPPORTED ((unsigned long)-1) > +#define TRNG_INVALID_PARAMETER ((unsigned long)-2) > +#define TRNG_NO_ENTROPY ((unsigned long)-3) > + > +#define MAX_BITS32 96 > +#define MAX_BITS64 192 > + > +static const uuid_t arm_smc_trng_uuid __aligned(4) = UUID_INIT( > + 0x023534a2, 0xe0bc, 0x45ec, 0x95, 0xdd, 0x33, 0x34, 0xc1, 0xcc, 0x31, 0x89); > + > +static int kvm_trng_do_rnd(struct kvm_vcpu *vcpu, int size) > +{ > + u32 num_bits = smccc_get_arg1(vcpu); > + u64 bits[3]; > + int i; > + > + if (num_bits > 3 * size) { > + smccc_set_retval(vcpu, TRNG_INVALID_PARAMETER, 0, 0, 0); > + return 1; > + } > + > + /* get as many bits as we need to fulfil the request */ > + for (i = 0; i < DIV_ROUND_UP(num_bits, 64); i++) > + /* use the arm64 specific backend directly if one exists */ > + if (!arch_get_random_seed_long((unsigned long *)&bits[i])) > + bits[i] = get_random_long(); > + > + if (num_bits % 64) > + bits[i - 1] &= U64_MAX >> (64 - (num_bits % 64)); > + > + while (i < ARRAY_SIZE(bits)) > + bits[i++] = 0; > + > + if (size == 32) > + smccc_set_retval(vcpu, TRNG_SUCCESS, lower_32_bits(bits[1]), > + upper_32_bits(bits[0]), lower_32_bits(bits[0])); > + else > + smccc_set_retval(vcpu, TRNG_SUCCESS, bits[2], bits[1], bits[0]); > + > + memzero_explicit(bits, sizeof(bits)); > + return 1; > +} > + > +int kvm_trng_call(struct kvm_vcpu *vcpu) > +{ > + const __le32 *u = (__le32 *)arm_smc_trng_uuid.b; > + u32 func_id = smccc_get_function(vcpu); > + unsigned long val = TRNG_NOT_SUPPORTED; > + int size = 64; > + > + switch (func_id) { > + case ARM_SMCCC_TRNG_VERSION: > + 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: > + val = TRNG_SUCCESS; > + } > + break; > + case ARM_SMCCC_TRNG_GET_UUID: > + smccc_set_retval(vcpu, le32_to_cpu(u[0]), le32_to_cpu(u[1]), > + le32_to_cpu(u[2]), le32_to_cpu(u[3])); > + return 1; > + case ARM_SMCCC_TRNG_RND32: > + size = 32; > + fallthrough; > + case ARM_SMCCC_TRNG_RND64: > + return kvm_trng_do_rnd(vcpu, size); > + } > + > + smccc_set_retval(vcpu, val, 0, 0, 0); > + return 1; > +} > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
