From 216887f79d9878d9cb169729fea3bb16c56db465 Mon Sep 17 00:00:00 2001 From: Ankit Agrawal Date: Sat, 5 Jul 2025 07:17:13 +0000 Subject: [PATCH] KVM: arm64: Assume non-PFNMAP/MIXEDMAP VMAs can be mapped cacheable Despite its name, kvm_is_device_pfn() is actually used to determine if a given PFN has a kernel mapping that can be used to perform cache maintenance, as it calls pfn_is_map_memory() internally. Expand the helper into its single callsite and further condition the check on the VMA having either VM_PFNMAP or VM_MIXEDMAP set. VMAs that set neither of these flags must always contain Normal, struct page backed memory with valid aliases in the kernel address space. Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Reviewed-by: David Hildenbrand Tested-by: Donald Dutile Signed-off-by: Ankit Agrawal Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20250705071717.5062-3-ankita@nvidia.com [ Oliver: fixed typos, refined changelog ] Signed-off-by: Oliver Upton --- arch/arm64/kvm/mmu.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 1601ab9527d44..5fe24f30999d3 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -193,11 +193,6 @@ int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, return 0; } -static bool kvm_is_device_pfn(unsigned long pfn) -{ - return !pfn_is_map_memory(pfn); -} - static void *stage2_memcache_zalloc_page(void *arg) { struct kvm_mmu_memory_cache *mc = arg; @@ -1492,6 +1487,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; struct kvm_pgtable *pgt; struct page *page; + vm_flags_t vm_flags; enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED; if (fault_is_perm) @@ -1619,6 +1615,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED; + vm_flags = vma->vm_flags; + /* Don't use the VMA after the unlock -- it may have vanished */ vma = NULL; @@ -1642,7 +1640,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (is_error_noslot_pfn(pfn)) return -EFAULT; - if (kvm_is_device_pfn(pfn)) { + if (vm_flags & (VM_PFNMAP | VM_MIXEDMAP) && !pfn_is_map_memory(pfn)) { /* * If the page was identified as device early by looking at * the VMA flags, vma_pagesize is already representing the -- 2.47.2