linux-kernel - [PATCH 6/6] KVM: Move flags check for user memory regions to the ioctl() specific API

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Message-ID: <20240802205003.353672-7-seanjc@google.com>
Date: Fri,  2 Aug 2024 13:50:03 -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 6/6] KVM: Move flags check for user memory regions to the
 ioctl() specific API

Move the check on memory region flags to kvm_vm_ioctl_set_memory_region()
now that the internal API, kvm_set_internal_memslot(), disallows any and
all flags.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 virt/kvm/kvm_main.c | 54 ++++++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 32 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 84fcb20e3e1c..09cc261b080a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1566,34 +1566,6 @@ static void kvm_replace_memslot(struct kvm *kvm,
 #define KVM_SET_USER_MEMORY_REGION_V1_FLAGS \
 	(KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)
 
-static int check_memory_region_flags(struct kvm *kvm,
-				     const struct kvm_userspace_memory_region2 *mem)
-{
-	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
-
-	if (kvm_arch_has_private_mem(kvm))
-		valid_flags |= KVM_MEM_GUEST_MEMFD;
-
-	/* Dirty logging private memory is not currently supported. */
-	if (mem->flags & KVM_MEM_GUEST_MEMFD)
-		valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
-
-#ifdef CONFIG_HAVE_KVM_READONLY_MEM
-	/*
-	 * GUEST_MEMFD is incompatible with read-only memslots, as writes to
-	 * read-only memslots have emulated MMIO, not page fault, semantics,
-	 * and KVM doesn't allow emulated MMIO for private memory.
-	 */
-	if (!(mem->flags & KVM_MEM_GUEST_MEMFD))
-		valid_flags |= KVM_MEM_READONLY;
-#endif
-
-	if (mem->flags & ~valid_flags)
-		return -EINVAL;
-
-	return 0;
-}
-
 static void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
 {
 	struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
@@ -1986,10 +1958,6 @@ static int kvm_set_memory_region(struct kvm *kvm,
 
 	lockdep_assert_held(&kvm->slots_lock);
 
-	r = check_memory_region_flags(kvm, mem);
-	if (r)
-		return r;
-
 	as_id = mem->slot >> 16;
 	id = (u16)mem->slot;
 
@@ -2114,6 +2082,28 @@ EXPORT_SYMBOL_GPL(kvm_set_internal_memslot);
 static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
 					  struct kvm_userspace_memory_region2 *mem)
 {
+	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
+
+	if (kvm_arch_has_private_mem(kvm))
+		valid_flags |= KVM_MEM_GUEST_MEMFD;
+
+	/* Dirty logging private memory is not currently supported. */
+	if (mem->flags & KVM_MEM_GUEST_MEMFD)
+		valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
+
+#ifdef CONFIG_HAVE_KVM_READONLY_MEM
+	/*
+	 * GUEST_MEMFD is incompatible with read-only memslots, as writes to
+	 * read-only memslots have emulated MMIO, not page fault, semantics,
+	 * and KVM doesn't allow emulated MMIO for private memory.
+	 */
+	if (!(mem->flags & KVM_MEM_GUEST_MEMFD))
+		valid_flags |= KVM_MEM_READONLY;
+#endif
+
+	if (mem->flags & ~valid_flags)
+		return -EINVAL;
+
 	if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
 		return -EINVAL;
 
-- 
2.46.0.rc2.264.g509ed76dc8-goog