Re: [Xen-devel] [PATCH v6 09/16] x86/hvm: limit reps to avoid the need to handle retry

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 09.07.15 at 13:11, <Paul.Durrant@xxxxxxxxxx> wrote:
>> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
>> Sent: 09 July 2015 11:05
>> >>> On 03.07.15 at 18:25, <paul.durrant@xxxxxxxxxx> wrote:
>> > @@ -287,17 +271,56 @@ static int hvmemul_do_io_addr(
>> >      bool_t is_mmio, paddr_t addr, unsigned long *reps,
>> >      unsigned int size, uint8_t dir, bool_t df, paddr_t ram_gpa)
>> >  {
>> > -    struct page_info *ram_page;
>> > +    struct vcpu *v = current;
>> > +    unsigned long ram_gmfn = paddr_to_pfn(ram_gpa);
>> > +    unsigned int page_off = ram_gpa & (PAGE_SIZE - 1);
>> > +    struct page_info *ram_page[2];
>> > +    int nr_pages = 0;
>> 
>> unsigned int
> 
> No, it's intentionally signed because the unwind code at the end of the 
> function is:
> 
>     while ( --nr_pages >= 0 )
>         hvmemul_release_page(ram_page[nr_pages]);
> 
> I.e. the loop terminates when nr_pages gets to -1.

     while ( nr_pages-- )
         hvmemul_release_page(ram_page[nr_pages]);

Jan


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