Commit 4e4f38f8 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

Merge tag 'kvm-memslots-6.14' of https://github.com/kvm-x86/linux into HEAD 

KVM kvm_set_memory_region() cleanups and hardening for 6.14:

 - Add proper lockdep assertions when setting memory regions.

 - Add a dedicated API for setting KVM-internal memory regions.

 - Explicitly disallow all flags for KVM-internal memory regions.
parents 5cf32aff 0cc3cb21

arch/x86/kvm/x86.c

+4 −3
Original line number Diff line number Diff line
@@ -12800,7 +12800,8 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, 
	struct kvm_memslots *slots = kvm_memslots(kvm);

	struct kvm_memory_slot *slot;



	/* Called with kvm->slots_lock held.  */

	lockdep_assert_held(&kvm->slots_lock);



	if (WARN_ON(id >= KVM_MEM_SLOTS_NUM))

		return ERR_PTR_USR(-EINVAL);
@@ -12833,7 +12834,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, 
		m.guest_phys_addr = gpa;

		m.userspace_addr = hva;

		m.memory_size = size;

		r = __kvm_set_memory_region(kvm, &m);

		r = kvm_set_internal_memslot(kvm, &m);

		if (r < 0)

			return ERR_PTR_USR(r);

	}
@@ -12934,7 +12935,7 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, 


	/*

	 * Clear out the previous array pointers for the KVM_MR_MOVE case.  The

	 * old arrays will be freed by __kvm_set_memory_region() if installing

	 * old arrays will be freed by kvm_set_memory_region() if installing

	 * the new memslot is successful.

	 */

	memset(&slot->arch, 0, sizeof(slot->arch));

include/linux/kvm_host.h

+3 −5
Original line number Diff line number Diff line
@@ -1183,7 +1183,7 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn 
 *   -- just change its flags

 *

 * Since flags can be changed by some of these operations, the following

 * differentiation is the best we can do for __kvm_set_memory_region():

 * differentiation is the best we can do for kvm_set_memory_region():

 */

enum kvm_mr_change {

	KVM_MR_CREATE,
@@ -1192,9 +1192,7 @@ enum kvm_mr_change { 
	KVM_MR_FLAGS_ONLY,

};



int kvm_set_memory_region(struct kvm *kvm,

			  const struct kvm_userspace_memory_region2 *mem);

int __kvm_set_memory_region(struct kvm *kvm,

int kvm_set_internal_memslot(struct kvm *kvm,

			     const struct kvm_userspace_memory_region2 *mem);

void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot);

void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen);

virt/kvm/kvm_main.c

+14 −19
Original line number Diff line number Diff line
@@ -1926,15 +1926,7 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, 
	return false;

}



/*

 * Allocate some memory and give it an address in the guest physical address

 * space.

 *

 * Discontiguous memory is allowed, mostly for framebuffers.

 *

 * Must be called holding kvm->slots_lock for write.

 */

int __kvm_set_memory_region(struct kvm *kvm,

static int kvm_set_memory_region(struct kvm *kvm,

				 const struct kvm_userspace_memory_region2 *mem)

{

	struct kvm_memory_slot *old, *new;
@@ -1945,6 +1937,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 
	int as_id, id;

	int r;



	lockdep_assert_held(&kvm->slots_lock);



	r = check_memory_region_flags(kvm, mem);

	if (r)

		return r;
@@ -2056,19 +2050,19 @@ int __kvm_set_memory_region(struct kvm *kvm, 
	kfree(new);

	return r;

}

EXPORT_SYMBOL_GPL(__kvm_set_memory_region);



int kvm_set_memory_region(struct kvm *kvm,

int kvm_set_internal_memslot(struct kvm *kvm,

			     const struct kvm_userspace_memory_region2 *mem)

{

	int r;

	if (WARN_ON_ONCE(mem->slot < KVM_USER_MEM_SLOTS))

		return -EINVAL;



	mutex_lock(&kvm->slots_lock);

	r = __kvm_set_memory_region(kvm, mem);

	mutex_unlock(&kvm->slots_lock);

	return r;

	if (WARN_ON_ONCE(mem->flags))

		return -EINVAL;



	return kvm_set_memory_region(kvm, mem);

}

EXPORT_SYMBOL_GPL(kvm_set_memory_region);

EXPORT_SYMBOL_GPL(kvm_set_internal_memslot);



static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,

					  struct kvm_userspace_memory_region2 *mem)
@@ -2076,6 +2070,7 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, 
	if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)

		return -EINVAL;



	guard(mutex)(&kvm->slots_lock);

	return kvm_set_memory_region(kvm, mem);

}