Re: [PATCH 4/6] KVM: arm64/mmu: avoid struct page in MMU

From: David Stevens <redacted>

Avoid converting pfns returned by follow_fault_pfn to struct pages to
transiently take a reference. The reference was originally taken to
match the reference taken by gup. However, pfns returned by
follow_fault_pfn may not have a struct page set up for reference
counting.

Signed-off-by: David Stevens <redacted>
---
 arch/arm64/kvm/mmu.c | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 896b3644b36f..a741972cb75f 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c

@@ -968,16 +968,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 */
 	if (vma_pagesize == PAGE_SIZE && !force_pte)
 		vma_pagesize = transparent_hugepage_adjust(memslot, hva,
-							   &pfn, &fault_ipa);
+							   &pfnpg, &fault_ipa);
 	if (writable)
 		prot |= KVM_PGTABLE_PROT_W;
 
 	if (fault_status != FSC_PERM && !device)
-		clean_dcache_guest_page(pfn, vma_pagesize);
+		clean_dcache_guest_page(pfnpg.pfn, vma_pagesize);
 
 	if (exec_fault) {
 		prot |= KVM_PGTABLE_PROT_X;
-		invalidate_icache_guest_page(pfn, vma_pagesize);
+		invalidate_icache_guest_page(pfnpg.pfn, vma_pagesize);