Commit d131f004 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: Assert slots_lock is held when setting memory regions 



Add proper lockdep assertions in __kvm_set_memory_region() and
__x86_set_memory_region() instead of relying comments.

Opportunistically delete __kvm_set_memory_region()'s entire function
comment as the API doesn't allocate memory or select a gfn, and the
"mostly for framebuffers" comment hasn't been true for a very long time.

Cc: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: default avatarChristoph Schlameuss <schlameuss@linux.ibm.com>
Link: https://lore.kernel.org/r/20250111002022.1230573-3-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent f81a6d12

arch/x86/kvm/x86.c

+2 −1
Original line number Diff line number Diff line
@@ -12793,7 +12793,8 @@ 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);

virt/kvm/kvm_main.c

+2 −8
Original line number Diff line number Diff line
@@ -1926,14 +1926,6 @@ 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,

			    const struct kvm_userspace_memory_region2 *mem)

{
@@ -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;