On Tue, Sep 17, 2019 at 04:31:39PM -0700, Sukadev Bhattiprolu wrote:
>
> Minor: Can this allocation be outside the lock? I guess it would change
> the order of cleanup at the end of the function.
Cleanup has bitmap_clear which needs be under spinlock, so this order
of setup/alloc and cleanup will keep things simple is what I felt.
>
> > + spin_unlock(&kvmppc_uvmem_pfn_lock);
> > +
> > + *rmap = uvmem_pfn | KVMPPC_RMAP_UVMEM_PFN;
> > + pvt->rmap = rmap;
> > + pvt->gpa = gpa;
> > + pvt->lpid = lpid;
> > + dpage->zone_device_data = pvt;
> > +
> > + get_page(dpage);
> > + return dpage;
> > +
> > +out_unlock:
> > + unlock_page(dpage);
> > +out_clear:
> > + bitmap_clear(kvmppc_uvmem_pfn_bitmap, uvmem_pfn - pfn_first, 1);
>
> Reuse variable 'bit' here?
Sure.
>
> > +out:
> > + spin_unlock(&kvmppc_uvmem_pfn_lock);
> > + return NULL;
> > +}
> > +
> > +/*
> > + * Alloc a PFN from private device memory pool and copy page from normal
> > + * memory to secure memory using UV_PAGE_IN uvcall.
> > + */
> > +static int
> > +kvmppc_svm_page_in(struct vm_area_struct *vma, unsigned long start,
> > + unsigned long end, unsigned long *rmap,
> > + unsigned long gpa, unsigned int lpid,
> > + unsigned long page_shift)
> > +{
> > + unsigned long src_pfn, dst_pfn = 0;
> > + struct migrate_vma mig;
> > + struct page *spage;
> > + unsigned long pfn;
> > + struct page *dpage;
> > + int ret = 0;
> > +
> > + memset(&mig, 0, sizeof(mig));
> > + mig.vma = vma;
> > + mig.start = start;
> > + mig.end = end;
> > + mig.src = &src_pfn;
> > + mig.dst = &dst_pfn;
> > +
> > + ret = migrate_vma_setup(&mig);
> > + if (ret)
> > + return ret;
> > +
> > + spage = migrate_pfn_to_page(*mig.src);
> > + pfn = *mig.src >> MIGRATE_PFN_SHIFT;
> > + if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE)) {
> > + ret = 0;
>
> Do we want to return success here (and have caller return H_SUCCESS) if
> we can't find the source page?
spage is NULL for zero page. In this case we return success but there is
no UV_PAGE_IN involved.
Absence of MIGRATE_PFN_MIGRATE indicates that the requested page
can't be migrated. I haven't hit this case till now. Similar check
is also present in the nouveau driver. I am not sure if this is strictly
needed here.
Christoph, Jason - do you know if !(*mig.src & MIGRATE_PFN_MIGRATE)
check is required and if so in which cases will it be true?
> > + * Fault handler callback when HV touches any page that has been
>
> Nit: s/callback/callback. Called /
Yeah will rephrase.
Regards,
Bharata.
