Add very basic OP-TEE mediator. It can probe for OP-TEE presence, tell it about domain creation/destruction and then return an error to all calls to the guest.
This code issues two non-preemptible calls to OP-TEE: to create and to destroy client context. They can't block in OP-TEE, as they are considered "fast calls" in terms of ARM SMCCC.
Signed-off-by: Volodymyr Babchuk volodymyr_babchuk@epam.com
---
All the patches to optee.c should be merged together. They were split to ease up review. But they depend heavily on each other.
Changes from v4: - Removed OPTEE_ENABLED macro. Empty (for now) struct optee_domain is used instead. - Removed forward_call() function, mediator now will return OPTEE_SMC_RETURN_ENOTAVAIL for all unimplemented calls - Fixed mistake when OPTEE_SMC_FUNCID_GET_OS_REVISION instead of OPTEE_SMC_CALL_GET_OS_REVISION was used - OP-TEE is informed about domain destruction in optee_relinquish_resources() - removed optee_domain_destroy() function because all job is done in the optee_relinquish_resources() function
Changes from v3: - Introduced optee_relinquish_resources() function to free mediator resources in a more controllable way
Changes from v2: - Fixed coding style - Introduced tee/Kconfig - Fixed error messages --- xen/arch/arm/Kconfig | 2 + xen/arch/arm/domain.c | 3 +- xen/arch/arm/tee/Kconfig | 4 + xen/arch/arm/tee/Makefile | 1 + xen/arch/arm/tee/optee.c | 166 ++++++++++++++++++++++++++++++++++ xen/include/asm-arm/domain.h | 3 + xen/include/public/arch-arm.h | 1 + 7 files changed, 179 insertions(+), 1 deletion(-) create mode 100644 xen/arch/arm/tee/Kconfig create mode 100644 xen/arch/arm/tee/optee.c
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index e527b2f885..99e6f0ebb2 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -237,3 +237,5 @@ source "arch/arm/platforms/Kconfig" source "common/Kconfig"
source "drivers/Kconfig" + +source "arch/arm/tee/Kconfig" diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c index 0c8e50f48f..94e6f47f75 100644 --- a/xen/arch/arm/domain.c +++ b/xen/arch/arm/domain.c @@ -649,7 +649,8 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config) return -EINVAL; }
- if ( config->arch.tee_type != XEN_DOMCTL_CONFIG_TEE_NONE ) + if ( config->arch.tee_type != XEN_DOMCTL_CONFIG_TEE_NONE && + config->arch.tee_type != tee_get_type() ) { dprintk(XENLOG_INFO, "Unsupported TEE type\n"); return -EINVAL; diff --git a/xen/arch/arm/tee/Kconfig b/xen/arch/arm/tee/Kconfig new file mode 100644 index 0000000000..5b829db2e9 --- /dev/null +++ b/xen/arch/arm/tee/Kconfig @@ -0,0 +1,4 @@ +config OPTEE + bool "Enable OP-TEE mediator" + default n + depends on TEE diff --git a/xen/arch/arm/tee/Makefile b/xen/arch/arm/tee/Makefile index c54d4796ff..982c879684 100644 --- a/xen/arch/arm/tee/Makefile +++ b/xen/arch/arm/tee/Makefile @@ -1 +1,2 @@ obj-y += tee.o +obj-$(CONFIG_OPTEE) += optee.o diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c new file mode 100644 index 0000000000..e9b69bd2d2 --- /dev/null +++ b/xen/arch/arm/tee/optee.c @@ -0,0 +1,166 @@ +/* + * xen/arch/arm/tee/optee.c + * + * OP-TEE mediator. It sits in between OP-TEE and guests and performs + * actual calls to OP-TEE when some guest tries to interact with + * OP-TEE. As OP-TEE does not know about second stage MMU translation, + * mediator does this translation and performs other housekeeping tasks. + * + * OP-TEE ABI/protocol is described in two header files: + * - optee_smc.h provides information about SMCs: all possible calls, + * register allocation and return codes. + * - optee_msg.h provides format for messages that are passed with + * standard call OPTEE_SMC_CALL_WITH_ARG. + * + * Volodymyr Babchuk volodymyr_babchuk@epam.com + * Copyright (c) 2018-2019 EPAM Systems. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <xen/device_tree.h> +#include <xen/sched.h> + +#include <asm/smccc.h> +#include <asm/tee/tee.h> +#include <asm/tee/optee_msg.h> +#include <asm/tee/optee_smc.h> + +/* Client ID 0 is reserved for the hypervisor itself */ +#define OPTEE_CLIENT_ID(domain) ((domain)->domain_id + 1) + +/* Domain context */ +struct optee_domain { +}; + +static bool optee_probe(void) +{ + struct dt_device_node *node; + struct arm_smccc_res resp; + + /* Check for entry in dtb */ + node = dt_find_compatible_node(NULL, NULL, "linaro,optee-tz"); + if ( !node ) + return false; + + /* Check UID */ + arm_smccc_smc(ARM_SMCCC_CALL_UID_FID(TRUSTED_OS_END), &resp); + + if ( (uint32_t)resp.a0 != OPTEE_MSG_UID_0 || + (uint32_t)resp.a1 != OPTEE_MSG_UID_1 || + (uint32_t)resp.a2 != OPTEE_MSG_UID_2 || + (uint32_t)resp.a3 != OPTEE_MSG_UID_3 ) + return false; + + return true; +} + +static int optee_domain_init(struct domain *d) +{ + struct arm_smccc_res resp; + struct optee_domain *ctx; + + ctx = xzalloc(struct optee_domain); + if ( !ctx ) + return -ENOMEM; + + /* + * Inform OP-TEE about a new guest. This is a "Fast" call in + * terms of OP-TEE. This basically means that it can't be + * preempted, because there is no thread allocated for it in + * OP-TEE. No blocking calls can be issued and interrupts are + * disabled. + * + * a7 should be 0, so we can't skip last 6 parameters of arm_smccc_smc() + */ + arm_smccc_smc(OPTEE_SMC_VM_CREATED, OPTEE_CLIENT_ID(d), 0, 0, 0, 0, 0, 0, + &resp); + if ( resp.a0 != OPTEE_SMC_RETURN_OK ) + { + printk(XENLOG_WARNING "%pd: Unable to create OPTEE client: rc = 0x%X\n", + d, (uint32_t)resp.a0); + + xfree(ctx); + + return -ENODEV; + } + + d->arch.tee = ctx; + + return 0; +} + +static int optee_relinquish_resources(struct domain *d) +{ + struct arm_smccc_res resp; + + if ( !d->arch.tee ) + return 0; + + /* + * Inform OP-TEE that domain is shutting down. This is + * also a fast SMC call, like OPTEE_SMC_VM_CREATED, so + * it is also non-preemptible. + * At this time all domain VCPUs should be stopped. OP-TEE + * relies on this. + * + * a7 should be 0, so we can't skip last 6 parameters of arm_smccc_smc() + */ + arm_smccc_smc(OPTEE_SMC_VM_DESTROYED, OPTEE_CLIENT_ID(d), 0, 0, 0, 0, 0, 0, + &resp); + + XFREE(d->arch.tee); + + return 0; +} + +static bool optee_handle_call(struct cpu_user_regs *regs) +{ + if ( !current->domain->arch.tee ) + return false; + + switch ( get_user_reg(regs, 0) ) + { + case OPTEE_SMC_CALLS_COUNT: + case OPTEE_SMC_CALLS_UID: + case OPTEE_SMC_CALLS_REVISION: + case OPTEE_SMC_CALL_GET_OS_UUID: + case OPTEE_SMC_CALL_GET_OS_REVISION: + case OPTEE_SMC_ENABLE_SHM_CACHE: + case OPTEE_SMC_DISABLE_SHM_CACHE: + case OPTEE_SMC_GET_SHM_CONFIG: + case OPTEE_SMC_EXCHANGE_CAPABILITIES: + case OPTEE_SMC_CALL_WITH_ARG: + case OPTEE_SMC_CALL_RETURN_FROM_RPC: + set_user_reg(regs, 0, OPTEE_SMC_RETURN_ENOTAVAIL); + return true; + + default: + return false; + } +} + +static const struct tee_mediator_ops optee_ops = +{ + .probe = optee_probe, + .domain_init = optee_domain_init, + .relinquish_resources = optee_relinquish_resources, + .handle_call = optee_handle_call, +}; + +REGISTER_TEE_MEDIATOR(optee, "OP-TEE", XEN_DOMCTL_CONFIG_TEE_OPTEE, &optee_ops); + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h index 0f15372098..2960a53e69 100644 --- a/xen/include/asm-arm/domain.h +++ b/xen/include/asm-arm/domain.h @@ -98,6 +98,9 @@ struct arch_domain struct vpl011 vpl011; #endif
+#ifdef CONFIG_TEE + void *tee; +#endif } __cacheline_aligned;
struct arch_vcpu diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h index 5e938a91cc..ced9545596 100644 --- a/xen/include/public/arch-arm.h +++ b/xen/include/public/arch-arm.h @@ -305,6 +305,7 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t); #define XEN_DOMCTL_CONFIG_GIC_V2 1 #define XEN_DOMCTL_CONFIG_GIC_V3 2 #define XEN_DOMCTL_CONFIG_TEE_NONE 0 +#define XEN_DOMCTL_CONFIG_TEE_OPTEE 1 struct xen_arch_domainconfig { /* IN/OUT */ uint8_t gic_version;