Re: [PATCH V2] libxc: fix xc_translate_foreign_address()

[Julien Grall <julien.grall@arm.com>]

On 05/04/17 16:03, Wei Liu wrote:
> On Wed, Apr 05, 2017 at 03:58:05PM +0100, Julien Grall wrote:
>> Hi Razvan,
>>
>> On 05/04/17 15:53, Razvan Cojocaru wrote:
>>> Currently xc_translate_foreign_address() only checks for the PSE bit on
>>> level 2 entries (that's 2 MB pages on x64 and 32-bit with PAE, and 4 MB
>>> pages on 32-bit). But the Linux kernel sometimes uses 1 GB pages. This
>>> patch fixes that, by checking the PSE bit on level 3 entries if the guest
>>> has 4 translation levels (that means 64-bit guests only).
>>>
>>> Signed-off-by: Cristian-Bogdan Sirb <csirb@bitdefender.com>
>>
>> He is the author of the patch, correct? If so, he should be the author as
>> well (e.g From: ...).
>>
>> Also, you may want to add your signed-off-by here.
>>
>
> Julien, if you agree to let this patch go in 4.9. I can fix those up.

Release-acked-by: Julien Grall <julien.grall@arm.com>

Cheers,

>
> Razvan, please tell me what you want me to do.
>
> Code-wise:
>
> Acked-by: Wei Liu <wei.liu2@citrix.com>
>
>
>> Cheers,
>>
>>> ---
>>> Changes since V1:
>>>  - Added header comment.
>>> ---
>>>  tools/libxc/include/xenctrl.h | 3 +++
>>>  tools/libxc/xc_pagetab.c      | 2 +-
>>>  2 files changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
>>> index 2d97d36..ca4bb6c 100644
>>> --- a/tools/libxc/include/xenctrl.h
>>> +++ b/tools/libxc/include/xenctrl.h
>>> @@ -1460,6 +1460,9 @@ int xc_lockprof_query(xc_interface *xch,
>>>  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size);
>>>
>>>  /**
>>> + * Avoid using this function, as it does not work for all cases (such
>>> + * as 4M superpages, or guests using PSE36). Only used for debugging.
>>> + *
>>>   * Translates a virtual address in the context of a given domain and
>>>   * vcpu returning the GFN containing the address (that is, an MFN for
>>>   * PV guests, a PFN for HVM guests).  Returns 0 for failure.
>>> diff --git a/tools/libxc/xc_pagetab.c b/tools/libxc/xc_pagetab.c
>>> index 92eebd6..db25c20 100644
>>> --- a/tools/libxc/xc_pagetab.c
>>> +++ b/tools/libxc/xc_pagetab.c
>>> @@ -93,7 +93,7 @@ unsigned long xc_translate_foreign_address(xc_interface *xch, uint32_t dom,
>>>              return 0;
>>>          }
>>>          paddr = pte & 0x000ffffffffff000ull;
>>> -        if (level == 2 && (pte & PTE_PSE)) {
>>> +        if ((level == 2 || (level == 3 && pt_levels == 4)) && (pte & PTE_PSE)) {
>>>              mask = ((mask ^ ~-mask) >> 1); /* All bits below first set bit */
>>>              return ((paddr & ~mask) | (virt & mask)) >> PAGE_SHIFT;
>>>          }
>>>
>>
>> --
>> Julien Grall

-- 
Julien Grall

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