[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC v13 08/20] pvh: PVH access to hypercalls
>>> On 27.09.13 at 23:15, Mukesh Rathor <mukesh.rathor@xxxxxxxxxx> wrote: > On Thu, 26 Sep 2013 16:33:07 +0100 > "Jan Beulich" <JBeulich@xxxxxxxx> wrote: > >> >>> On 23.09.13 at 18:49, George Dunlap <george.dunlap@xxxxxxxxxxxxx> >> >>> wrote: >> > --- a/xen/arch/x86/hvm/mtrr.c >> > +++ b/xen/arch/x86/hvm/mtrr.c >> > @@ -578,6 +578,7 @@ int32_t hvm_set_mem_pinned_cacheattr( >> > { >> > struct hvm_mem_pinned_cacheattr_range *range; >> > >> > + /* Side note: A PVH guest writes to MSR_IA32_CR_PAT natively. >> > */ if ( !((type == PAT_TYPE_UNCACHABLE) || >> > (type == PAT_TYPE_WRCOMB) || >> > (type == PAT_TYPE_WRTHROUGH) || >> >> I always wondered what this comment is trying to tell the >> reader. > > Original code: > > /* Side note: A PVH guest writes to MSR_IA32_CR_PAT natively. */ > if ( is_pvh_domain(d) ) > return -EOPNOTSUPP; > > We don't support this because the guest writes PAT natively, was > my intention. Either it was your comment to return EOPNOTSUPP > or just my thought - it will return EINVAL now, I guess ok too. That wasn't the question (albeit nevertheless good you comment on it). I was really after understanding what "writes natively" is supposed to mean. _If_ there's any behavioral difference to how "normal" HVM accesses the PAT MSR, this surely requires (in the commit message at least) a more detailed explanation. And if there was no difference, the comment would seem rather pointless. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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