linux-kernel - [PATCH 2/6] KVM: Assert slots_lock is held in __kvm_set_memory

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Message-ID: <20240802205003.353672-3-seanjc@google.com>
Date: Fri,  2 Aug 2024 13:49:59 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/6] KVM: Assert slots_lock is held in  __kvm_set_memory_region()

Add a proper lockdep assertion in __kvm_set_memory_region() instead of
relying on a function comment.  Opportunistically delete the 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.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 virt/kvm/kvm_main.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0557d663b69b..f202bdbfca9e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1973,14 +1973,6 @@ 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)
 {
@@ -1992,6 +1984,8 @@ 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;
-- 
2.46.0.rc2.264.g509ed76dc8-goog