Commit f39b80e3 authored by Paul Durrant's avatar Paul Durrant Committed by Sean Christopherson
Browse files

KVM: pfncache: Add a map helper function 



There is a pfncache unmap helper but mapping is open-coded. Arguably this
is fine because mapping is done in only one place, hva_to_pfn_retry(), but
adding the helper does make that function more readable.

No functional change intended.

Signed-off-by: default avatarPaul Durrant <pdurrant@amazon.com>
Reviewed-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240215152916.1158-2-paul@xen.org


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent db7d6fbc

virt/kvm/pfncache.c

+29 −18
Original line number Diff line number Diff line
@@ -96,18 +96,33 @@ bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len) 
}

EXPORT_SYMBOL_GPL(kvm_gpc_check);



static void gpc_unmap_khva(kvm_pfn_t pfn, void *khva)

static void *gpc_map(kvm_pfn_t pfn)

{

	/* Unmap the old pfn/page if it was mapped before. */

	if (!is_error_noslot_pfn(pfn) && khva) {

	if (pfn_valid(pfn))

		return kmap(pfn_to_page(pfn));



#ifdef CONFIG_HAS_IOMEM

	return memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);

#else

	return NULL;

#endif

}



static void gpc_unmap(kvm_pfn_t pfn, void *khva)

{

	/* Unmap the old pfn/page if it was mapped before. */

	if (is_error_noslot_pfn(pfn) || !khva)

		return;



	if (pfn_valid(pfn)) {

		kunmap(pfn_to_page(pfn));

		return;

	}



#ifdef CONFIG_HAS_IOMEM

		else

	memunmap(khva);

#endif

}

}



static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_seq)

{
@@ -175,7 +190,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) 
			 * the existing mapping and didn't create a new one.

			 */

			if (new_khva != old_khva)

				gpc_unmap_khva(new_pfn, new_khva);

				gpc_unmap(new_pfn, new_khva);



			kvm_release_pfn_clean(new_pfn);
@@ -193,15 +208,11 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) 
		 * too must be done outside of gpc->lock!

		 */

		if (gpc->usage & KVM_HOST_USES_PFN) {

			if (new_pfn == gpc->pfn) {

			if (new_pfn == gpc->pfn)

				new_khva = old_khva;

			} else if (pfn_valid(new_pfn)) {

				new_khva = kmap(pfn_to_page(new_pfn));

#ifdef CONFIG_HAS_IOMEM

			} else {

				new_khva = memremap(pfn_to_hpa(new_pfn), PAGE_SIZE, MEMREMAP_WB);

#endif

			}

			else

				new_khva = gpc_map(new_pfn);



			if (!new_khva) {

				kvm_release_pfn_clean(new_pfn);

				goto out_error;
@@ -326,7 +337,7 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, 
	mutex_unlock(&gpc->refresh_lock);



	if (unmap_old)

		gpc_unmap_khva(old_pfn, old_khva);

		gpc_unmap(old_pfn, old_khva);



	return ret;

}
@@ -412,7 +423,7 @@ void kvm_gpc_deactivate(struct gfn_to_pfn_cache *gpc) 
		list_del(&gpc->list);

		spin_unlock(&kvm->gpc_lock);



		gpc_unmap_khva(old_pfn, old_khva);

		gpc_unmap(old_pfn, old_khva);

	}

}

EXPORT_SYMBOL_GPL(kvm_gpc_deactivate);