Re: [PATCH v9 6/7] x86/sgx: Add hook to error injection address validation

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, 2021-10-11 at 11:59 -0700, Tony Luck wrote:
> SGX reserved memory does not appear in the standard address maps.
> 
> Add hook to call into the SGX code to check if an address is located
> in SGX memory.
> 
> There are other challenges in injecting errors into SGX. Update the
> documentation with a sequence of operations to inject.
> 
> Tested-by: Reinette Chatre <reinette.chatre@intel.com>
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
>  .../firmware-guide/acpi/apei/einj.rst         | 19 +++++++++++++++++++
>  drivers/acpi/apei/einj.c                      |  3 ++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/firmware-guide/acpi/apei/einj.rst b/Documentation/firmware-guide/acpi/apei/einj.rst
> index c042176e1707..55e2331a6438 100644
> --- a/Documentation/firmware-guide/acpi/apei/einj.rst
> +++ b/Documentation/firmware-guide/acpi/apei/einj.rst
> @@ -181,5 +181,24 @@ You should see something like this in dmesg::
>    [22715.834759] EDAC sbridge MC3: PROCESSOR 0:306e7 TIME 1422553404 SOCKET 0 APIC 0
>    [22716.616173] EDAC MC3: 1 CE memory read error on CPU_SrcID#0_Channel#0_DIMM#0 (channel:0 slot:0 page:0x12345 offset:0x0 grain:32 syndrome:0x0 -  area:DRAM err_code:0001:0090 socket:0
> channel_mask:1 rank:0)
>  
> +Special notes for injection into SGX enclaves:
> +
> +There may be a separate BIOS setup option to enable SGX injection.
> +
> +The injection process consists of setting some special memory controller
> +trigger that will inject the error on the next write to the target
> +address. But the h/w prevents any software outside of an SGX enclave
> +from accessing enclave pages (even BIOS SMM mode).
> +
> +The following sequence can be used:
> +  1) Determine physical address of enclave page
> +  2) Use "notrigger=1" mode to inject (this will setup
> +     the injection address, but will not actually inject)
> +  3) Enter the enclave
> +  4) Store data to the virtual address matching physical address from step 1
> +  5) Execute CLFLUSH for that virtual address
> +  6) Spin delay for 250ms
> +  7) Read from the virtual address. This will trigger the error
> +
>  For more information about EINJ, please refer to ACPI specification
>  version 4.0, section 17.5 and ACPI 5.0, section 18.6.
> diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c
> index 2882450c443e..67c335baad52 100644
> --- a/drivers/acpi/apei/einj.c
> +++ b/drivers/acpi/apei/einj.c
> @@ -544,7 +544,8 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
>             ((region_intersects(base_addr, size, IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE)
>                                 != REGION_INTERSECTS) &&
>              (region_intersects(base_addr, size, IORESOURCE_MEM, IORES_DESC_PERSISTENT_MEMORY)
> -                               != REGION_INTERSECTS)))
> +                               != REGION_INTERSECTS) &&
> +            !arch_is_platform_page(base_addr)))
>                 return -EINVAL;
>  
>  inject:

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

/Jarkko