Subject: linux-next: manual merge of the hmm tree with the kvm-ppc tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 30 Jul 2020 19:16:10 +1000

Hi all,

Today's linux-next merge of the hmm tree got a conflict in:

  arch/powerpc/kvm/book3s_hv_uvmem.c

between commit:

  f1b87ea8784b ("KVM: PPC: Book3S HV: Move kvmppc_svm_page_out up")

from the kvm-ppc tree and commit:

  5143192cd410 ("mm/migrate: add a flags parameter to migrate_vma")

from the hmm tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc arch/powerpc/kvm/book3s_hv_uvmem.c
index 0d49e3425a12,6850bd04bcb9..000000000000
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@@ -496,94 -253,14 +496,95 @@@ unsigned long kvmppc_h_svm_init_start(s
  	return ret;
  }
  
 -unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
 +/*
 + * Provision a new page on HV side and copy over the contents
 + * from secure memory using UV_PAGE_OUT uvcall.
 + * Caller must held kvm->arch.uvmem_lock.
 + */
 +static int __kvmppc_svm_page_out(struct vm_area_struct *vma,
 +		unsigned long start,
 +		unsigned long end, unsigned long page_shift,
 +		struct kvm *kvm, unsigned long gpa)
  {
 -	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
 -		return H_UNSUPPORTED;
 +	unsigned long src_pfn, dst_pfn = 0;
 +	struct migrate_vma mig;
 +	struct page *dpage, *spage;
 +	struct kvmppc_uvmem_page_pvt *pvt;
 +	unsigned long pfn;
 +	int ret = U_SUCCESS;
  
 -	kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
 -	pr_info("LPID %d went secure\n", kvm->arch.lpid);
 -	return H_SUCCESS;
 +	memset(&mig, 0, sizeof(mig));
 +	mig.vma = vma;
 +	mig.start = start;
 +	mig.end = end;
 +	mig.src = &src_pfn;
 +	mig.dst = &dst_pfn;
- 	mig.src_owner = &kvmppc_uvmem_pgmap;
++	mig.pgmap_owner = &kvmppc_uvmem_pgmap;
++	mig.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
 +
 +	/* The requested page is already paged-out, nothing to do */
 +	if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
 +		return ret;
 +
 +	ret = migrate_vma_setup(&mig);
 +	if (ret)
 +		return -1;
 +
 +	spage = migrate_pfn_to_page(*mig.src);
 +	if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
 +		goto out_finalize;
 +
 +	if (!is_zone_device_page(spage))
 +		goto out_finalize;
 +
 +	dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
 +	if (!dpage) {
 +		ret = -1;
 +		goto out_finalize;
 +	}
 +
 +	lock_page(dpage);
 +	pvt = spage->zone_device_data;
 +	pfn = page_to_pfn(dpage);
 +
 +	/*
 +	 * This function is used in two cases:
 +	 * - When HV touches a secure page, for which we do UV_PAGE_OUT
 +	 * - When a secure page is converted to shared page, we *get*
 +	 *   the page to essentially unmap the device page. In this
 +	 *   case we skip page-out.
 +	 */
 +	if (!pvt->skip_page_out)
 +		ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
 +				  gpa, 0, page_shift);
 +
 +	if (ret == U_SUCCESS)
 +		*mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
 +	else {
 +		unlock_page(dpage);
 +		__free_page(dpage);
 +		goto out_finalize;
 +	}
 +
 +	migrate_vma_pages(&mig);
 +
 +out_finalize:
 +	migrate_vma_finalize(&mig);
 +	return ret;
 +}
 +
 +static inline int kvmppc_svm_page_out(struct vm_area_struct *vma,
 +				      unsigned long start, unsigned long end,
 +				      unsigned long page_shift,
 +				      struct kvm *kvm, unsigned long gpa)
 +{
 +	int ret;
 +
 +	mutex_lock(&kvm->arch.uvmem_lock);
 +	ret = __kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa);
 +	mutex_unlock(&kvm->arch.uvmem_lock);
 +
 +	return ret;
  }
  
  /*
@@@ -744,7 -400,20 +745,8 @@@ static int kvmppc_svm_page_in(struct vm
  	mig.end = end;
  	mig.src = &src_pfn;
  	mig.dst = &dst_pfn;
+ 	mig.flags = MIGRATE_VMA_SELECT_SYSTEM;
  
 -	/*
 -	 * We come here with mmap_lock write lock held just for
 -	 * ksm_madvise(), otherwise we only need read mmap_lock.
 -	 * Hence downgrade to read lock once ksm_madvise() is done.
 -	 */
 -	ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
 -			  MADV_UNMERGEABLE, &vma->vm_flags);
 -	mmap_write_downgrade(kvm->mm);
 -	*downgrade = true;
 -	if (ret)
 -		return ret;
 -
  	ret = migrate_vma_setup(&mig);
  	if (ret)
  		return ret;