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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6 01/10] xen/arm: add generic TEE mediator framework
On Tue, 11 Jun 2019, Volodymyr Babchuk wrote:
> This patch adds basic framework for TEE mediators. Guests can't talk
> to TEE directly, we need some entity that will intercept request
> and decide what to do with them. "TEE mediator" is a such entity.
>
> This is how it works: user can build XEN with multiple TEE mediators
> (see the next patches, where OP-TEE mediator is introduced).
> TEE mediator register self with REGISTER_TEE_MEDIATOR() macro in the
> same way, as device drivers use DT_DEVICE_START()/DT_DEVICE_END()
> macros.
>
> At run-time, during initialization, framework calls probe() function
> for each available mediator driver to find which TEE is installed
> on the platform. Then generic vSMC handler will call selected mediator
> when it intercept SMC/HVC that belongs to TEE OS or TEE application.
>
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> ---
> Changes from v5:
> - Fixed bug, when XEN won't boot with CONFIG_TEE=n
> - Fixed coding style
> - Added __read_mostly attribute to *cur_mediator variable
>
> Changes from v4:
> - Added tee_get_type() function, which returns id of currently
> available TEE
> - Removed "dom0_tee_enabled" command line option. Dom0 now always
> uses currently available TEE.
> - Added TEE type sanity check in arch_sanitise_domain_config()
> - tee_domain_init() now internally checks if requested TEE type
> corresponds to available TEE
> - removed tee_domain_destroy() function because it is not used
> by anyone
>
> Changes from v3:
>
> - tee_enable() renamed to tee_domain_init()
> - Added tee_relinquish_resources() function along with
> changes to domain_relinquish_resources()
> - Added command-line parameter dom0_tee_enabled, which controls
> if tee is enabled for Dom0. It is disabled by default
> - Instead of boolean tee state (enabled/disabled) I introduced
> enumeration with two values: none or native. It is possible
> to add other types of tee in the future
>
> Changes from v2:
> - Removed empty tee/Kconfig file
>
> Changes from v1:
> - Removed tee_remove() function
> - CONFIG_TEE depends on EXPERT
> - tee_domain_created() converted to tee_enable()
> - tee_init() is called using initcall() mechanism
> - tee_handle_smc() renamed to tee_handle_call()
>
> Changes from "RFC" version:
> - renamed CONFIG_ARM_TEE to CONFIG_TEE
> - changed discovery mechanism: instead of UUID mathing, TEE-specific
> probing is used
> ---
> MAINTAINERS | 6 ++
> xen/arch/arm/Kconfig | 7 +++
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/domain.c | 18 ++++++
> xen/arch/arm/setup.c | 2 +
> xen/arch/arm/tee/Makefile | 1 +
> xen/arch/arm/tee/tee.c | 98 +++++++++++++++++++++++++++++
> xen/arch/arm/vsmc.c | 5 ++
> xen/arch/arm/xen.lds.S | 7 +++
> xen/include/asm-arm/domain.h | 1 +
> xen/include/asm-arm/tee/tee.h | 112 ++++++++++++++++++++++++++++++++++
> xen/include/public/arch-arm.h | 5 ++
> 12 files changed, 263 insertions(+)
> create mode 100644 xen/arch/arm/tee/Makefile
> create mode 100644 xen/arch/arm/tee/tee.c
> create mode 100644 xen/include/asm-arm/tee/tee.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6fbdc2bdcb..ab32e7f409 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -381,6 +381,12 @@ F: config/Stubdom.mk.in
> F: m4/stubdom.m4
> F: stubdom/
>
> +TEE MEDIATORS
> +M: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> +S: Supported
> +F: xen/arch/arm/tee/
> +F: xen/include/asm-arm/tee
> +
> TOOLSTACK
> M: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> M: Wei Liu <wl@xxxxxxx>
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index 585b57f023..caaf377a33 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -106,6 +106,13 @@ config HARDEN_BRANCH_PREDICTOR
>
> If unsure, say Y.
>
> +config TEE
> + bool "Enable TEE mediators support" if EXPERT = "y"
> + default n
> + help
> + This option enables generic TEE mediators support. It allows guests
> + to access real TEE via one of TEE mediators implemented in XEN.
> +
> endmenu
>
> menu "ARM errata workaround via the alternative framework"
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index cb902cb6fe..5c2aa34557 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -5,6 +5,7 @@ subdir-$(CONFIG_ACPI) += acpi
> ifneq ($(CONFIG_NO_PLAT),y)
> subdir-y += platforms
> endif
> +subdir-$(CONFIG_TEE) += tee
>
> obj-$(CONFIG_HAS_ALTERNATIVE) += alternative.o
> obj-y += bootfdt.init.o
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index ad1b106bd7..d27a137f7a 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -32,6 +32,7 @@
> #include <asm/platform.h>
> #include <asm/procinfo.h>
> #include <asm/regs.h>
> +#include <asm/tee/tee.h>
> #include <asm/vfp.h>
> #include <asm/vgic.h>
> #include <asm/vtimer.h>
> @@ -647,6 +648,12 @@ int arch_sanitise_domain_config(struct
> xen_domctl_createdomain *config)
> return -EINVAL;
> }
>
> + if ( config->arch.tee_type != XEN_DOMCTL_CONFIG_TEE_NONE )
> + {
> + dprintk(XENLOG_INFO, "Unsupported TEE type\n");
> + return -EINVAL;
> + }
> +
> return 0;
> }
>
> @@ -704,6 +711,9 @@ int arch_domain_create(struct domain *d,
> if ( (rc = domain_vtimer_init(d, &config->arch)) != 0 )
> goto fail;
>
> + if ( (rc = tee_domain_init(d, config->arch.tee_type)) != 0 )
> + goto fail;
> +
> update_domain_wallclock_time(d);
>
> /*
> @@ -948,6 +958,14 @@ int domain_relinquish_resources(struct domain *d)
> */
> domain_vpl011_deinit(d);
>
> + d->arch.relmem = RELMEM_tee;
> + /* Fallthrough */
> +
> + case RELMEM_tee:
> + ret = tee_relinquish_resources(d);
> + if (ret )
> + return ret;
> +
> d->arch.relmem = RELMEM_xen;
> /* Fallthrough */
>
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 5af49c7a08..1643f91f1c 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -49,6 +49,7 @@
> #include <asm/platform.h>
> #include <asm/procinfo.h>
> #include <asm/setup.h>
> +#include <asm/tee/tee.h>
> #include <xsm/xsm.h>
> #include <asm/acpi.h>
>
> @@ -894,6 +895,7 @@ void __init start_xen(unsigned long boot_phys_offset,
> dom0_cfg.arch.nr_spis = min(gic_number_lines(), (unsigned int) 992) - 32;
> if ( gic_number_lines() > 992 )
> printk(XENLOG_WARNING "Maximum number of vGIC IRQs exceeded.\n");
> + dom0_cfg.arch.tee_type = tee_get_type();
> dom0_cfg.max_vcpus = dom0_max_vcpus();
>
> dom0 = domain_create(0, &dom0_cfg, true);
> diff --git a/xen/arch/arm/tee/Makefile b/xen/arch/arm/tee/Makefile
> new file mode 100644
> index 0000000000..c54d4796ff
> --- /dev/null
> +++ b/xen/arch/arm/tee/Makefile
> @@ -0,0 +1 @@
> +obj-y += tee.o
> diff --git a/xen/arch/arm/tee/tee.c b/xen/arch/arm/tee/tee.c
> new file mode 100644
> index 0000000000..3964a8a5cd
> --- /dev/null
> +++ b/xen/arch/arm/tee/tee.c
> @@ -0,0 +1,98 @@
> +/*
> + * xen/arch/arm/tee/tee.c
> + *
> + * Generic part of TEE mediator subsystem
> + *
> + * Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> + * 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/errno.h>
> +#include <xen/init.h>
> +#include <xen/types.h>
> +
> +#include <asm/tee/tee.h>
> +
> +extern const struct tee_mediator_desc _steemediator[], _eteemediator[];
> +static const struct tee_mediator_desc __read_mostly *cur_mediator;
> +
> +/*
> + * TODO: Add function to alter Dom0 DTB, so we can properly describe
> + * present TEE.
> + */
> +
> +bool tee_handle_call(struct cpu_user_regs *regs)
> +{
> + if ( unlikely(!cur_mediator) )
> + return false;
> +
> + return cur_mediator->ops->handle_call(regs);
> +}
> +
> +int tee_domain_init(struct domain *d, uint16_t tee_type)
> +{
> + if ( tee_type == XEN_DOMCTL_CONFIG_TEE_NONE )
> + return 0;
> +
> + if ( !cur_mediator )
> + return -ENODEV;
> +
> + if ( cur_mediator->tee_type != tee_type )
> + return -EINVAL;
> +
> + return cur_mediator->ops->domain_init(d);
> +}
> +
> +int tee_relinquish_resources(struct domain *d)
> +{
> + if ( !cur_mediator )
> + return 0;
> +
> + return cur_mediator->ops->relinquish_resources(d);
> +}
> +
> +uint16_t tee_get_type(void)
> +{
> + if ( !cur_mediator )
> + return XEN_DOMCTL_CONFIG_TEE_NONE;
> +
> + return cur_mediator->tee_type;
> +}
> +
> +
> +static int __init tee_init(void)
> +{
> + const struct tee_mediator_desc *desc;
> +
> + for ( desc = _steemediator; desc != _eteemediator; desc++ )
> + {
> + if ( desc->ops->probe() )
> + {
> + printk(XENLOG_INFO "Using TEE mediator for %s\n", desc->name);
> + cur_mediator = desc;
> + return 0;
> + }
> + }
> +
> + return 0;
> +}
> +
> +__initcall(tee_init);
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
> index c72b9a04ff..f8e350311d 100644
> --- a/xen/arch/arm/vsmc.c
> +++ b/xen/arch/arm/vsmc.c
> @@ -23,6 +23,7 @@
> #include <asm/monitor.h>
> #include <asm/regs.h>
> #include <asm/smccc.h>
> +#include <asm/tee/tee.h>
> #include <asm/traps.h>
> #include <asm/vpsci.h>
> #include <asm/platform.h>
> @@ -276,6 +277,10 @@ static bool vsmccc_handle_call(struct cpu_user_regs
> *regs)
> case ARM_SMCCC_OWNER_SIP:
> handled = platform_smc(regs);
> break;
> + case ARM_SMCCC_OWNER_TRUSTED_APP ... ARM_SMCCC_OWNER_TRUSTED_APP_END:
> + case ARM_SMCCC_OWNER_TRUSTED_OS ... ARM_SMCCC_OWNER_TRUSTED_OS_END:
> + handled = tee_handle_call(regs);
> + break;
> }
> }
>
> diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
> index 1e72906477..e664c4441a 100644
> --- a/xen/arch/arm/xen.lds.S
> +++ b/xen/arch/arm/xen.lds.S
> @@ -137,6 +137,13 @@ SECTIONS
> _aedevice = .;
> } :text
>
> + . = ALIGN(8);
> + .teemediator.info : {
> + _steemediator = .;
> + *(.teemediator.info)
> + _eteemediator = .;
> + } :text
> +
> . = ALIGN(PAGE_SIZE); /* Init code and data */
> __init_begin = .;
> .init.text : {
> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> index 312fec8932..0f15372098 100644
> --- a/xen/include/asm-arm/domain.h
> +++ b/xen/include/asm-arm/domain.h
> @@ -58,6 +58,7 @@ struct arch_domain
> /* Continuable domain_relinquish_resources(). */
> enum {
> RELMEM_not_started,
> + RELMEM_tee,
> RELMEM_xen,
> RELMEM_page,
> RELMEM_mapping,
> diff --git a/xen/include/asm-arm/tee/tee.h b/xen/include/asm-arm/tee/tee.h
> new file mode 100644
> index 0000000000..f483986385
> --- /dev/null
> +++ b/xen/include/asm-arm/tee/tee.h
> @@ -0,0 +1,112 @@
> +/*
> + * xen/include/asm-arm/tee/tee.h
> + *
> + * Generic part of TEE mediator subsystem
> + *
> + * Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> + * Copyright (c) 2018 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.
> + */
> +
> +#ifndef __ARCH_ARM_TEE_TEE_H__
> +#define __ARCH_ARM_TEE_TEE_H__
> +
> +#include <xen/lib.h>
> +#include <xen/types.h>
> +
> +#include <asm/regs.h>
> +
> +#ifdef CONFIG_TEE
> +
> +struct tee_mediator_ops {
> + /*
> + * Probe for TEE. Should return true if TEE found and
> + * mediator is initialized.
> + */
> + bool (*probe)(void);
> +
> + /*
> + * Called during domain construction if toolstack requests to enable
> + * TEE support so mediator can inform TEE about new
> + * guest and create own structures for the new domain.
> + */
> + int (*domain_init)(struct domain *d);
> +
> + /*
> + * Called during domain destruction to relinquish resources used
> + * by mediator itself. This function can return -ERESTART to indicate
> + * that it does not finished work and should be called again.
> + */
> + int (*relinquish_resources)(struct domain *d);
> +
> + /* Handle SMCCC call for current domain. */
> + bool (*handle_call)(struct cpu_user_regs *regs);
> +};
> +
> +struct tee_mediator_desc {
> + /* Printable name of the TEE. */
> + const char *name;
> +
> + /* Mediator callbacks as described above. */
> + const struct tee_mediator_ops *ops;
> +
> + /*
> + * ID of TEE. Corresponds to xen_arch_domainconfig.tee_type.
> + * Should be one of XEN_DOMCTL_CONFIG_TEE_xxx
> + */
> + uint16_t tee_type;
> +};
> +
> +bool tee_handle_call(struct cpu_user_regs *regs);
> +int tee_domain_init(struct domain *d, uint16_t tee_type);
> +int tee_relinquish_resources(struct domain *d);
> +uint16_t tee_get_type(void);
> +
> +#define REGISTER_TEE_MEDIATOR(_name, _namestr, _type, _ops) \
> +static const struct tee_mediator_desc __tee_desc_##_name __used \
> +__section(".teemediator.info") = { \
> + .name = _namestr, \
> + .ops = _ops, \
> + .tee_type = _type \
> +}
> +
> +#else
> +
> +static inline bool tee_handle_call(struct cpu_user_regs *regs)
> +{
> + return false;
> +}
> +
> +static inline int tee_domain_init(struct domain *d, uint16_t tee_type)
> +{
> + if ( likely(tee_type == XEN_DOMCTL_CONFIG_TEE_NONE) )
> + return 0;
> +
> + return -ENODEV;
> +}
> +
> +static inline int tee_relinquish_resources(struct domain *d)
> +{
> + return 0;
> +}
> +
> +static inline uint16_t tee_get_type(void)
> +{
> + return XEN_DOMCTL_CONFIG_TEE_NONE;
> +}
> +
> +#endif /* CONFIG_TEE */
> +
> +#endif /* __ARCH_ARM_TEE_TEE_H__ */
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
> index eb424e8286..bb69c380ec 100644
> --- a/xen/include/public/arch-arm.h
> +++ b/xen/include/public/arch-arm.h
> @@ -304,10 +304,15 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
> #define XEN_DOMCTL_CONFIG_GIC_NATIVE 0
> #define XEN_DOMCTL_CONFIG_GIC_V2 1
> #define XEN_DOMCTL_CONFIG_GIC_V3 2
> +
> +#define XEN_DOMCTL_CONFIG_TEE_NONE 0
> +
> struct xen_arch_domainconfig {
> /* IN/OUT */
> uint8_t gic_version;
> /* IN */
> + uint16_t tee_type;
> + /* IN */
> uint32_t nr_spis;
> /*
> * OUT
> --
> 2.21.0
>
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