Re: [Xen-devel] [PATCH v2 03/15] xen/arm: vsmc: Implement SMCCC 1.1

[Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>]

Hi,

On 08.02.18 21:21, Julien Grall wrote:
> The new SMC Calling Convention (v1.1) allows for a reduced overhead
> when calling into the firmware, and provides a new feature discovery 
> mechanism. See "Firmware interfaces for mitigating CVE-2017-5715" ARM
> DEN 00070A.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>

> --- Changes in v2: - Add a humand readable name for the
> specification --- xen/arch/arm/vpsci.c        |  1 + 
> xen/arch/arm/vsmc.c         | 23 +++++++++++++++++++++++ 
> xen/include/asm-arm/smccc.h | 15 +++++++++++++++ 3 files changed, 39
> insertions(+)
>
> diff --git a/xen/arch/arm/vpsci.c b/xen/arch/arm/vpsci.c index
> e82b62db1a..19ee7caeb4 100644 --- a/xen/arch/arm/vpsci.c +++
> b/xen/arch/arm/vpsci.c @@ -212,6 +212,7 @@ static int32_t
> do_psci_1_0_features(uint32_t psci_func_id) case
> PSCI_0_2_FN32_SYSTEM_OFF: case PSCI_0_2_FN32_SYSTEM_RESET: case
> PSCI_1_0_FN32_PSCI_FEATURES: +    case ARM_SMCCC_VERSION_FID: return
> 0; default: return PSCI_NOT_SUPPORTED; diff --git
> a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c index
> 3d3bd95fee..a708aa5e81 100644 --- a/xen/arch/arm/vsmc.c +++
> b/xen/arch/arm/vsmc.c @@ -81,6 +81,26 @@ static bool
> fill_function_call_count(struct cpu_user_regs *regs, uint32_t cnt) 
> return true; }
> +/* SMCCC interface for ARM Architecture */ +static bool
> handle_arch(struct cpu_user_regs *regs) +{ +    uint32_t fid =
> (uint32_t)get_user_reg(regs, 0); + +    switch ( fid ) +    { +
> case ARM_SMCCC_VERSION_FID: +        set_user_reg(regs, 0,
> ARM_SMCCC_VERSION_1_1); +        return true; + +    case
> ARM_SMCCC_ARCH_FEATURES_FID: +        /* Nothing supported yet */ +
> set_user_reg(regs, 0, -1); +        return true; +    } + +    return
> false; +} + /* SMCCC interface for hypervisor. Tell about itself. */ 
> static bool handle_hypervisor(struct cpu_user_regs *regs) { @@ -188,6
> +208,9 @@ static bool vsmccc_handle_call(struct cpu_user_regs *regs) 
> { switch ( smccc_get_owner(funcid) ) { +        case
> ARM_SMCCC_OWNER_ARCH: +            handled = handle_arch(regs); +
> break; case ARM_SMCCC_OWNER_HYPERVISOR: handled =
> handle_hypervisor(regs); break; diff --git
> a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h index
> 62b3a8cdf5..431389c118 100644 --- a/xen/include/asm-arm/smccc.h +++
> b/xen/include/asm-arm/smccc.h @@ -16,6 +16,9 @@ #ifndef
> __ASM_ARM_SMCCC_H__ #define __ASM_ARM_SMCCC_H__
>
> +#define ARM_SMCCC_VERSION_1_0   0x10000 +#define
> ARM_SMCCC_VERSION_1_1   0x10001 + /* * This file provides common
> defines for ARM SMC Calling Convention as * specified in @@ -100,6
> +103,18 @@ static inline uint32_t smccc_get_owner(register_t funcid) 
> ARM_SMCCC_OWNER_##owner,     \ 0xFF03)
> +#define ARM_SMCCC_VERSION_FID                       \ +
> ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,         \ +
> ARM_SMCCC_CONV_32,           \ +
> ARM_SMCCC_OWNER_ARCH,        \ +                       0x0)
> \ + +#define ARM_SMCCC_ARCH_FEATURES_FID                 \ +
> ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,         \ +
> ARM_SMCCC_CONV_32,           \ +
> ARM_SMCCC_OWNER_ARCH,        \ +                       0x1) + /* Only
> one error code defined in SMCCC */ #define
> ARM_SMCCC_ERR_UNKNOWN_FUNCTION  (-1)
--
Volodymyr Babchuk

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