[Xen-devel] 答复: [PATCH v2 2/2] x86/dmar: zap DMAR signature for dom0 once in TBOOT case

[Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>]

Please ignore this patch, looks description is wrong, I'll resend, sorry for 
noise.

Zhenzhong
----- zhenzhong.duan@xxxxxxxxxx wrote：

> When TBOOT enabled, acpi_parse_dmar() zap a copy of DMAR table rather
> than the real table, so make it controled by config option based on
> the
> fact that we already have done the real zapping in
> tboot_parse_dmar_table().
> 
> As said above, acpi_parse_dmar() doesn't zaps APCI DMAR signature in
> real TXT heap table, fix the stale comments.
> 
> This is osmetic change, it's unnecessory to zap a copy of DMAR table
> which
> is freed later.
> 
> -v2: Add some description per Jan.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> ---
>  xen/arch/x86/tboot.c               |    3 +--
>  xen/drivers/passthrough/vtd/dmar.c |    2 ++
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
> index d5a5292..f22fa24 100644
> --- a/xen/arch/x86/tboot.c
> +++ b/xen/arch/x86/tboot.c
> @@ -490,8 +490,7 @@ int __init
> tboot_parse_dmar_table(acpi_table_handler dmar_handler)
>      rc = dmar_handler(dmar_table);
>      xfree(dmar_table);
>  
> -    /* acpi_parse_dmar() zaps APCI DMAR signature in TXT heap table
> */
> -    /* but dom0 will read real table, so must zap it there too */
> +    /* Dom0 will read real DMAR table, so must zap it there */
>      acpi_dmar_zap();
>  
>      return rc;
> diff --git a/xen/drivers/passthrough/vtd/dmar.c
> b/xen/drivers/passthrough/vtd/dmar.c
> index 8c5fa80..ed4c04e 100644
> --- a/xen/drivers/passthrough/vtd/dmar.c
> +++ b/xen/drivers/passthrough/vtd/dmar.c
> @@ -866,8 +866,10 @@ static int __init acpi_parse_dmar(struct
> acpi_table_header *table)
>      }
>  
>  out:
> +#ifndef CONFIG_TBOOT
>      /* Zap ACPI DMAR signature to prevent dom0 using vt-d HW. */
>      acpi_dmar_zap();
> +#endif
>      return ret;
>  }
>  
> -- 
> 1.7.3

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