Re: [Xen-devel] [PATCH v2 2/2] x86/mm: merge ptwr and mmio_ro page fault handlers

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.09.17 at 15:50, <wei.liu2@xxxxxxxxxx> wrote:
> On Fri, Sep 01, 2017 at 02:46:27PM +0100, Wei Liu wrote:
>> On Fri, Sep 01, 2017 at 03:38:49AM -0600, Jan Beulich wrote:
>> > > +                     struct cpu_user_regs *regs)
>> > > +{
>> > > +    l1_pgentry_t pte;
>> > > +    struct domain *d = v->domain;
>> > > +    unsigned int addr_size = is_pv_32bit_vcpu(v) ? 32 : BITS_PER_LONG;
>> > > +    struct x86_emulate_ctxt ctxt = {
>> > > +        .regs      = regs,
>> > > +        .vendor    = d->arch.cpuid->x86_vendor,
>> > > +        .addr_size = addr_size,
>> > > +        .sp_size   = addr_size,
>> > > +        .lma       = !is_pv_32bit_vcpu(v),
>> > 
>> > ... both is_pv_32bit_vcpu() accesses here (which internally use
>> > v->domain). In fact I wonder whether it wouldn't yield more
>> > consistent code if you didn't pass in the domain at all, as this
>> > must strictly be current->domain, or invoking x86_emulate() and
>> > various other functions is bogus. You'd then latch this into currd
>> > here.
>> > 
>> > Furthermore I think this second use could become "addr_size > 32".
>> > 
>> 
>> Sorry, second use of what?
> 
> Oh, you mean
> 
>    .lma = addr_size > 32

Yes.

Jan


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