Re: [PATCH v5 2/6] x86: rearrange how mod_l*_entry() functions call UPDATE_ENTRY

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.11.2026 15:10, Jan Beulich wrote:
> On 12.11.2026 14:56, Andrew Cooper wrote:
>> On 12/11/2026 10:00 am, Kevin Lampis wrote:
>>> --- a/xen/arch/x86/mm.c
>>> +++ b/xen/arch/x86/mm.c
>>> @@ -2197,12 +2197,12 @@ static int mod_l1_entry(l1_pgentry_t *pl1e, 
>>> l1_pgentry_t nl1e,
>>>  {
>>>      l1_pgentry_t ol1e = l1e_read(pl1e);
>>>      struct domain *pt_dom = pt_vcpu->domain;
>>> -    int rc = 0;
>>>  
>>>      ASSERT(!paging_mode_refcounts(pt_dom));
>>>  
>>>      if ( l1e_get_flags(nl1e) & _PAGE_PRESENT )
>>>      {
>>> +        int rc;
>>>          struct page_info *page = NULL;
>>>          uint32_t disallow = l1_disallow_mask(pt_dom);
>>>  
>>> @@ -2276,16 +2276,14 @@ static int mod_l1_entry(l1_pgentry_t *pl1e, 
>>> l1_pgentry_t nl1e,
>>>          }
>>>          if ( page )
>>>              put_page(page);
>>> -
>>> -        UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
>>>      }
>>>      else if ( pv_l1tf_check_l1e(pt_dom, nl1e) )
>>>          return -ERESTART;
>>> -    else
>>> -        UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
>>> +
>>> +    UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
>>>  
>>>      put_page_from_l1e(ol1e, pt_dom);
>>> -    return rc;
>>> +    return 0;
>>>  }
>>>  
>>>  
>>> @@ -2300,7 +2298,6 @@ static int mod_l2_entry(l2_pgentry_t *pl2e,
>>>      struct domain *d = vcpu->domain;
>>>      struct page_info *l2pg = mfn_to_page(mfn);
>>>      unsigned long type = l2pg->u.inuse.type_info;
>>> -    int rc = 0;
>>>  
>>>      if ( unlikely(!is_guest_l2_slot(d, type, pgentry_ptr_to_slot(pl2e))) )
>>>      {
>>> @@ -2313,6 +2310,8 @@ static int mod_l2_entry(l2_pgentry_t *pl2e,
>>>  
>>>      if ( l2e_get_flags(nl2e) & _PAGE_PRESENT )
>>>      {
>>> +        int rc;
>>> +
>>>          if ( unlikely(l2e_get_flags(nl2e) & L2_DISALLOW_MASK) )
>>>          {
>>>              gdprintk(XENLOG_WARNING, "Bad L2 flags %x\n",
>>> @@ -2331,17 +2330,15 @@ static int mod_l2_entry(l2_pgentry_t *pl2e,
>>>  
>>>          if ( unlikely((rc = get_page_from_l2e(nl2e, mfn, d, 0)) < 0) )
>>>              return rc;
>>
>> Looking further through the call tree, I'm now confident that
>> get_page_from_l?e() can't return a positive number.
> 
> They can return L{2,4}E_RECURSIVE (i.e. 1).

Oh, sorry, these constants are still only local to my tree.

Jan