KVM: arm64: Replace force_pte with a max_map_size attribute

force_pte is annoyingly limited in what it expresses, and we'd
be better off with a more generic primitive. Introduce max_map_size
instead, which does the trick and can be moved into the vma_info
structure. This firther allows it to reduce the scopes in which
it is mutable.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index f749b5a2f893ea4bdd369b373004ecaaf56cbe4a..422b1b4f662d3d9bf4a84023f060d8949f607aed 100644 (file)
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1650,6 +1650,7 @@ struct kvm_s2_fault_vma_info {
        unsigned long   mmu_seq;
        long            vma_pagesize;
        vm_flags_t      vm_flags;
+       unsigned long   max_map_size;
        struct page     *page;
        kvm_pfn_t       pfn;
        gfn_t           gfn;
@@ -1659,14 +1660,18 @@ struct kvm_s2_fault_vma_info {
 };
 
 static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
-                                    struct vm_area_struct *vma, bool *force_pte)
+                                    struct kvm_s2_fault_vma_info *s2vi,
+                                    struct vm_area_struct *vma)
 {
        short vma_shift;
 
-       if (*force_pte)
+       if (memslot_is_logging(s2fd->memslot)) {
+               s2vi->max_map_size = PAGE_SIZE;
                vma_shift = PAGE_SHIFT;
-       else
+       } else {
+               s2vi->max_map_size = PUD_SIZE;
                vma_shift = get_vma_page_shift(vma, s2fd->hva);
+       }
 
        switch (vma_shift) {
 #ifndef __PAGETABLE_PMD_FOLDED
@@ -1684,7 +1689,7 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
                fallthrough;
        case CONT_PTE_SHIFT:
                vma_shift = PAGE_SHIFT;
-               *force_pte = true;
+               s2vi->max_map_size = PAGE_SIZE;
                fallthrough;
        case PAGE_SHIFT:
                break;
@@ -1695,7 +1700,7 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
        if (s2fd->nested) {
                unsigned long max_map_size;
 
-               max_map_size = *force_pte ? PAGE_SIZE : PUD_SIZE;
+               max_map_size = min(s2vi->max_map_size, PUD_SIZE);
 
                /*
                 * If we're about to create a shadow stage 2 entry, then we
@@ -1713,7 +1718,7 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
                else if (max_map_size >= PAGE_SIZE && max_map_size < PMD_SIZE)
                        max_map_size = PAGE_SIZE;
 
-               *force_pte = (max_map_size == PAGE_SIZE);
+               s2vi->max_map_size = max_map_size;
                vma_shift = min_t(short, vma_shift, __ffs(max_map_size));
        }
 
@@ -1722,7 +1727,6 @@ static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
 
 struct kvm_s2_fault {
        bool s2_force_noncacheable;
-       bool force_pte;
        enum kvm_pgtable_prot prot;
 };
 
@@ -1746,7 +1750,7 @@ static int kvm_s2_fault_get_vma_info(const struct kvm_s2_fault_desc *s2fd,
                return -EFAULT;
        }
 
-       s2vi->vma_pagesize = BIT(kvm_s2_resolve_vma_size(s2fd, vma, &fault->force_pte));
+       s2vi->vma_pagesize = BIT(kvm_s2_resolve_vma_size(s2fd, s2vi, vma));
 
        /*
         * Both the canonical IPA and fault IPA must be aligned to the
@@ -1931,7 +1935,7 @@ static int kvm_s2_fault_map(const struct kvm_s2_fault_desc *s2fd,
         * backed by a THP and thus use block mapping if possible.
         */
        if (mapping_size == PAGE_SIZE &&
-           !(fault->force_pte || fault->s2_force_noncacheable)) {
+           !(s2vi->max_map_size == PAGE_SIZE || fault->s2_force_noncacheable)) {
                if (perm_fault_granule > PAGE_SIZE) {
                        mapping_size = perm_fault_granule;
                } else {
@@ -1992,7 +1996,6 @@ static int user_mem_abort(const struct kvm_s2_fault_desc *s2fd)
        bool perm_fault = kvm_vcpu_trap_is_permission_fault(s2fd->vcpu);
        struct kvm_s2_fault_vma_info s2vi = {};
        struct kvm_s2_fault fault = {
-               .force_pte = memslot_is_logging(s2fd->memslot),
                .prot = KVM_PGTABLE_PROT_R,
        };
        void *memcache;