Commit e300614f authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: cleanup and add shortcuts to kvm_range_has_memory_attributes() 



Use a guard to simplify early returns, and add two more easy
shortcuts.  If the requested attributes are invalid, the attributes
xarray will never show them as set.  And if testing a single page,
kvm_get_memory_attributes() is more efficient.

Reviewed-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent de802524

virt/kvm/kvm_main.c

+20 −22
Original line number Diff line number Diff line
@@ -2398,6 +2398,14 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm, 
#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */



#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES

static u64 kvm_supported_mem_attributes(struct kvm *kvm)

{

	if (!kvm || kvm_arch_has_private_mem(kvm))

		return KVM_MEMORY_ATTRIBUTE_PRIVATE;



	return 0;

}



/*

 * Returns true if _all_ gfns in the range [@start, @end) have attributes

 * matching @attrs.
@@ -2406,40 +2414,30 @@ bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end, 
				     unsigned long attrs)

{

	XA_STATE(xas, &kvm->mem_attr_array, start);

	unsigned long mask = kvm_supported_mem_attributes(kvm);

	unsigned long index;

	bool has_attrs;

	void *entry;



	rcu_read_lock();

	if (attrs & ~mask)

		return false;



	if (!attrs) {

		has_attrs = !xas_find(&xas, end - 1);

		goto out;

	}

	if (end == start + 1)

		return kvm_get_memory_attributes(kvm, start) == attrs;



	guard(rcu)();

	if (!attrs)

		return !xas_find(&xas, end - 1);



	has_attrs = true;

	for (index = start; index < end; index++) {

		do {

			entry = xas_next(&xas);

		} while (xas_retry(&xas, entry));



		if (xas.xa_index != index || xa_to_value(entry) != attrs) {

			has_attrs = false;

			break;

		}

	}



out:

	rcu_read_unlock();

	return has_attrs;

		if (xas.xa_index != index || xa_to_value(entry) != attrs)

			return false;

	}



static u64 kvm_supported_mem_attributes(struct kvm *kvm)

{

	if (!kvm || kvm_arch_has_private_mem(kvm))

		return KVM_MEMORY_ATTRIBUTE_PRIVATE;



	return 0;

	return true;

}



static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,