Commit 7fbdda31 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: guest_memfd: do not go through struct page 



We have a perfectly usable folio, use it to retrieve the pfn and order.
All that's needed is a version of folio_file_page that returns a pfn.

Reviewed-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d04c77d2

virt/kvm/guest_memfd.c

+17 −10
Original line number Diff line number Diff line
@@ -13,6 +13,18 @@ struct kvm_gmem { 
	struct list_head entry;

};



/**

 * folio_file_pfn - like folio_file_page, but return a pfn.

 * @folio: The folio which contains this index.

 * @index: The index we want to look up.

 *

 * Return: The pfn for this index.

 */

static inline kvm_pfn_t folio_file_pfn(struct folio *folio, pgoff_t index)

{

	return folio_pfn(folio) + (index & (folio_nr_pages(folio) - 1));

}



static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct folio *folio)

{

#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
@@ -22,7 +34,6 @@ static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct fol 
	list_for_each_entry(gmem, gmem_list, entry) {

		struct kvm_memory_slot *slot;

		struct kvm *kvm = gmem->kvm;

		struct page *page;

		kvm_pfn_t pfn;

		gfn_t gfn;

		int rc;
@@ -34,13 +45,12 @@ static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct fol 
		if (!slot)

			continue;



		page = folio_file_page(folio, index);

		pfn = page_to_pfn(page);

		pfn = folio_file_pfn(folio, index);

		gfn = slot->base_gfn + index - slot->gmem.pgoff;

		rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, compound_order(compound_head(page)));

		rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio));

		if (rc) {

			pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",

					    index, gfn, pfn, rc);

			pr_warn_ratelimited("gmem: Failed to prepare folio for GFN %llx PFN %llx error %d.\n",

					    gfn, pfn, rc);

			return rc;

		}

	}
@@ -548,7 +558,6 @@ __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, 
	pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff;

	struct kvm_gmem *gmem = file->private_data;

	struct folio *folio;

	struct page *page;



	if (file != slot->gmem.file) {

		WARN_ON_ONCE(slot->gmem.file);
@@ -571,9 +580,7 @@ __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, 
		return ERR_PTR(-EHWPOISON);

	}



	page = folio_file_page(folio, index);



	*pfn = page_to_pfn(page);

	*pfn = folio_file_pfn(folio, index);

	if (max_order)

		*max_order = 0;