KVM: extend kvm_range_has_memory_attributes() to check subset of attributes

While currently there is no other attribute than KVM_MEMORY_ATTRIBUTE_PRIVATE,
KVM code such as kvm_mem_is_private() is written to expect their existence.
Allow using kvm_range_has_memory_attributes() as a multi-page version of
kvm_mem_is_private(), without it breaking later when more attributes are
introduced.

Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 26ef5b6ac3c1c0b0b76bdf4e38b4d062d615ff8a..43a02891babb23125f52de7fa5373b4bca539b49 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7513,7 +7513,7 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
        const unsigned long end = start + KVM_PAGES_PER_HPAGE(level);
 
        if (level == PG_LEVEL_2M)
-               return kvm_range_has_memory_attributes(kvm, start, end, attrs);
+               return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs);
 
        for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
                if (hugepage_test_mixed(slot, gfn, level - 1) ||

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 45373d42f3141fd6b20f7cefd81b2e3f6bbe0373..c223b97df03e2f2255dfa72b704b141be5172628 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2414,7 +2414,7 @@ static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn
 }
 
 bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
-                                    unsigned long attrs);
+                                    unsigned long mask, unsigned long attrs);
 bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
                                        struct kvm_gfn_range *range);
 bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 30328ff2d8407c7e14776e3b4ffa8b9d1505db93..92901656a0d413651741ebd069d335f8f5f161be 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2408,21 +2408,21 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
 
 /*
  * Returns true if _all_ gfns in the range [@start, @end) have attributes
- * matching @attrs.
+ * such that the bits in @mask match @attrs.
  */
 bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
-                                    unsigned long attrs)
+                                    unsigned long mask, unsigned long attrs)
 {
        XA_STATE(xas, &kvm->mem_attr_array, start);
-       unsigned long mask = kvm_supported_mem_attributes(kvm);
        unsigned long index;
        void *entry;
 
+       mask &= kvm_supported_mem_attributes(kvm);
        if (attrs & ~mask)
                return false;
 
        if (end == start + 1)
-               return kvm_get_memory_attributes(kvm, start) == attrs;
+               return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
 
        guard(rcu)();
        if (!attrs)
@@ -2433,7 +2433,8 @@ bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
                        entry = xas_next(&xas);
                } while (xas_retry(&xas, entry));
 
-               if (xas.xa_index != index || xa_to_value(entry) != attrs)
+               if (xas.xa_index != index ||
+                   (xa_to_value(entry) & mask) != attrs)
                        return false;
        }
 
@@ -2532,7 +2533,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
        mutex_lock(&kvm->slots_lock);
 
        /* Nothing to do if the entire range as the desired attributes. */
-       if (kvm_range_has_memory_attributes(kvm, start, end, attributes))
+       if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
                goto out_unlock;
 
        /*