Re: [PATCH v3 3/3] xen: prevent access to HPET from Dom0

["Roger Pau Monné" <roger.pau@citrix.com>]

El 22/01/15 a les 16.47, Jan Beulich ha escrit:
>>>> On 22.01.15 at 16:19, <roger.pau@citrix.com> wrote:
>> --- a/xen/arch/x86/domain_build.c
>> +++ b/xen/arch/x86/domain_build.c
>> @@ -36,6 +36,7 @@
>>  #include <asm/bzimage.h> /* for bzimage_parse */
>>  #include <asm/io_apic.h>
>>  #include <asm/hap.h>
>> +#include <asm/hpet.h> /* for hpet_address */
> 
> Please drop the comment - with hpet_flags it's now stale
> 
>> @@ -1495,6 +1499,16 @@ int __init construct_dom0(
>>              rc |= iomem_deny_access(d, sfn, efn);
>>      }
>>  
>> +    /* Prevent access to HPET */
>> +    if ( hpet_address != 0 )
>> +    {
>> +        mfn = paddr_to_pfn(hpet_address);
>> +        if ( hpet_flags & ACPI_HPET_PAGE_PROTECT4 )
> 
> The constant isn't a binary mask, you need to also use
> ACPI_HPET_PAGE_PROTECT_MASK. I further can't see why
> you wouldn't want to also handle ACPI_HPET_PAGE_PROTECT64.

Right, for PAGE_PROTECT64 we can also block access to the adjacent 15 pages.

Roger.