KVM: x86/mmu: Add KVM_RMAP_MANY to replace open coded '1' and '1ul' literals

Replace all of the open coded '1' literals used to mark a PTE list as
having many/multiple entries with a proper define.  It's hard enough to
read the code with one magic bit, and a future patch to support "locking"
a single rmap will add another.

No functional change intended.

Link: https://lore.kernel.org/r/20240809194335.1726916-17-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 24ca233..53e2489 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -912,6 +912,7 @@ static struct kvm_memory_slot *gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu
  * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
  * pte_list_desc containing more mappings.
  */
+#define KVM_RMAP_MANY  BIT(0)
 
 /*
  * Returns the number of pointers in the rmap chain, not counting the new one.
@@ -924,16 +925,16 @@ static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
 
        if (!rmap_head->val) {
                rmap_head->val = (unsigned long)spte;
-       } else if (!(rmap_head->val & 1)) {
+       } else if (!(rmap_head->val & KVM_RMAP_MANY)) {
                desc = kvm_mmu_memory_cache_alloc(cache);
                desc->sptes[0] = (u64 *)rmap_head->val;
                desc->sptes[1] = spte;
                desc->spte_count = 2;
                desc->tail_count = 0;
-               rmap_head->val = (unsigned long)desc | 1;
+               rmap_head->val = (unsigned long)desc | KVM_RMAP_MANY;
                ++count;
        } else {
-               desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+               desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
                count = desc->tail_count + desc->spte_count;
 
                /*
@@ -942,10 +943,10 @@ static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
                 */
                if (desc->spte_count == PTE_LIST_EXT) {
                        desc = kvm_mmu_memory_cache_alloc(cache);
-                       desc->more = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+                       desc->more = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
                        desc->spte_count = 0;
                        desc->tail_count = count;
-                       rmap_head->val = (unsigned long)desc | 1;
+                       rmap_head->val = (unsigned long)desc | KVM_RMAP_MANY;
                }
                desc->sptes[desc->spte_count++] = spte;
        }
@@ -956,7 +957,7 @@ static void pte_list_desc_remove_entry(struct kvm *kvm,
                                       struct kvm_rmap_head *rmap_head,
                                       struct pte_list_desc *desc, int i)
 {
-       struct pte_list_desc *head_desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+       struct pte_list_desc *head_desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
        int j = head_desc->spte_count - 1;
 
        /*
@@ -985,7 +986,7 @@ static void pte_list_desc_remove_entry(struct kvm *kvm,
        if (!head_desc->more)
                rmap_head->val = 0;
        else
-               rmap_head->val = (unsigned long)head_desc->more | 1;
+               rmap_head->val = (unsigned long)head_desc->more | KVM_RMAP_MANY;
        mmu_free_pte_list_desc(head_desc);
 }
 
@@ -998,13 +999,13 @@ static void pte_list_remove(struct kvm *kvm, u64 *spte,
        if (KVM_BUG_ON_DATA_CORRUPTION(!rmap_head->val, kvm))
                return;
 
-       if (!(rmap_head->val & 1)) {
+       if (!(rmap_head->val & KVM_RMAP_MANY)) {
                if (KVM_BUG_ON_DATA_CORRUPTION((u64 *)rmap_head->val != spte, kvm))
                        return;
 
                rmap_head->val = 0;
        } else {
-               desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+               desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
                while (desc) {
                        for (i = 0; i < desc->spte_count; ++i) {
                                if (desc->sptes[i] == spte) {
@@ -1037,12 +1038,12 @@ static bool kvm_zap_all_rmap_sptes(struct kvm *kvm,
        if (!rmap_head->val)
                return false;
 
-       if (!(rmap_head->val & 1)) {
+       if (!(rmap_head->val & KVM_RMAP_MANY)) {
                mmu_spte_clear_track_bits(kvm, (u64 *)rmap_head->val);
                goto out;
        }
 
-       desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+       desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
 
        for (; desc; desc = next) {
                for (i = 0; i < desc->spte_count; i++)
@@ -1062,10 +1063,10 @@ unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
 
        if (!rmap_head->val)
                return 0;
-       else if (!(rmap_head->val & 1))
+       else if (!(rmap_head->val & KVM_RMAP_MANY))
                return 1;
 
-       desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+       desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
        return desc->tail_count + desc->spte_count;
 }
 
@@ -1127,13 +1128,13 @@ static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head,
        if (!rmap_head->val)
                return NULL;
 
-       if (!(rmap_head->val & 1)) {
+       if (!(rmap_head->val & KVM_RMAP_MANY)) {
                iter->desc = NULL;
                sptep = (u64 *)rmap_head->val;
                goto out;
        }
 
-       iter->desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+       iter->desc = (struct pte_list_desc *)(rmap_head->val & ~KVM_RMAP_MANY);
        iter->pos = 0;
        sptep = iter->desc->sptes[iter->pos];
 out: