Re: [PATCH 1/2] x86/tboot: invalidate FIX_TBOOT_MAP_ADDRESS mapping after use

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 18/02/15 09:03, Jan Beulich wrote:
> In order for commit cbeeaa7d ("x86/nmi: fix shootdown of pcpus
> running in VMX non-root mode")'s re-use of that fixmap entry to not
> cause undesirable (in crash context) cross-CPU TLB flushes, invalidate
> the fixmap entry right after use.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>
> --- a/xen/arch/x86/tboot.c
> +++ b/xen/arch/x86/tboot.c
> @@ -138,6 +138,7 @@ void __init tboot_probe(void)
>                        TXT_PUB_CONFIG_REGS_BASE + TXTCR_SINIT_BASE);
>      tboot_copy_memory((unsigned char *)&sinit_size, sizeof(sinit_size),
>                        TXT_PUB_CONFIG_REGS_BASE + TXTCR_SINIT_SIZE);
> +    __set_fixmap(FIX_TBOOT_MAP_ADDRESS, 0, 0);
>  }
>  
>  /* definitions from xen/drivers/passthrough/vtd/iommu.h
> @@ -476,6 +477,8 @@ int __init tboot_parse_dmar_table(acpi_t
>      dmar_table_raw = xmalloc_array(unsigned char, dmar_table_length);
>      tboot_copy_memory(dmar_table_raw, dmar_table_length, pa);
>      dmar_table = (struct acpi_table_header *)dmar_table_raw;
> +    __set_fixmap(FIX_TBOOT_MAP_ADDRESS, 0, 0);
> +
>      rc = dmar_handler(dmar_table);
>      xfree(dmar_table_raw);
>  
>
>
>