[PATCH v7 04/29] KVM: Use "new" memslot's address space ID instead of dedicated param

From: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Igor Mammedov <imammedo@redhat.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Huacai Chen <chenhuacai@kernel.org>,
	Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
	Paul Mackerras <paulus@ozlabs.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Anup Patel <anup.patel@wdc.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Ben Gardon <bgardon@google.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v7 04/29] KVM: Use "new" memslot's address space ID instead of dedicated param
Date: Mon,  6 Dec 2021 20:54:10 +0100	[thread overview]
Message-ID: <03189577be214ab8530a4b3a3ee3ed1c2f9e5815.1638817639.git.maciej.szmigiero@oracle.com> (raw)
In-Reply-To: <cover.1638817637.git.maciej.szmigiero@oracle.com>

From: Sean Christopherson <seanjc@google.com>

Now that the address space ID is stored in every slot, including fake
slots used for deletion, use the slot's as_id instead of passing in the
redundant information as a param to kvm_set_memslot().  This will greatly
simplify future memslot work by avoiding passing a large number of
variables around purely to honor @as_id.

Drop a comment in the DELETE path about new->as_id being provided purely
for debug, as that's now a lie.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
---
 virt/kvm/kvm_main.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 95616392ff91..683a5ef6f71e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1553,7 +1553,7 @@ static void kvm_copy_memslots_arch(struct kvm_memslots *to,
 
 static int kvm_set_memslot(struct kvm *kvm,
 			   const struct kvm_userspace_memory_region *mem,
-			   struct kvm_memory_slot *new, int as_id,
+			   struct kvm_memory_slot *new,
 			   enum kvm_mr_change change)
 {
 	struct kvm_memory_slot *slot, old;
@@ -1576,7 +1576,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 	 */
 	mutex_lock(&kvm->slots_arch_lock);
 
-	slots = kvm_dup_memslots(__kvm_memslots(kvm, as_id), change);
+	slots = kvm_dup_memslots(__kvm_memslots(kvm, new->as_id), change);
 	if (!slots) {
 		mutex_unlock(&kvm->slots_arch_lock);
 		return -ENOMEM;
@@ -1596,7 +1596,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 		 * dropped by update_memslots anyway.  We'll also revert to the
 		 * old memslots if preparing the new memory region fails.
 		 */
-		slots = install_new_memslots(kvm, as_id, slots);
+		slots = install_new_memslots(kvm, new->as_id, slots);
 
 		/* From this point no new shadow pages pointing to a deleted,
 		 * or moved, memslot will be created.
@@ -1618,7 +1618,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 		 * to retrieve memslots *after* acquiring slots_arch_lock, thus
 		 * the active memslots are guaranteed to be fresh.
 		 */
-		kvm_copy_memslots_arch(slots, __kvm_memslots(kvm, as_id));
+		kvm_copy_memslots_arch(slots, __kvm_memslots(kvm, new->as_id));
 	}
 
 	/*
@@ -1635,7 +1635,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 		WARN_ON_ONCE(change != KVM_MR_CREATE);
 		memset(&old, 0, sizeof(old));
 		old.id = new->id;
-		old.as_id = as_id;
+		old.as_id = new->as_id;
 	}
 
 	/* Copy the arch-specific data, again after (re)acquiring slots_arch_lock. */
@@ -1646,7 +1646,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 		goto out_slots;
 
 	update_memslots(slots, new, change);
-	slots = install_new_memslots(kvm, as_id, slots);
+	slots = install_new_memslots(kvm, new->as_id, slots);
 
 	/*
 	 * Update the total number of memslot pages before calling the arch
@@ -1668,7 +1668,7 @@ static int kvm_set_memslot(struct kvm *kvm,
 
 out_slots:
 	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
-		slots = install_new_memslots(kvm, as_id, slots);
+		slots = install_new_memslots(kvm, new->as_id, slots);
 	else
 		mutex_unlock(&kvm->slots_arch_lock);
 	kvfree(slots);
@@ -1740,13 +1740,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
 		memset(&new, 0, sizeof(new));
 		new.id = id;
-		/*
-		 * This is only for debugging purpose; it should never be
-		 * referenced for a removed memslot.
-		 */
 		new.as_id = as_id;
 
-		return kvm_set_memslot(kvm, mem, &new, as_id, KVM_MR_DELETE);
+		return kvm_set_memslot(kvm, mem, &new, KVM_MR_DELETE);
 	}
 
 	new.as_id = as_id;
@@ -1809,7 +1805,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 			bitmap_set(new.dirty_bitmap, 0, new.npages);
 	}
 
-	r = kvm_set_memslot(kvm, mem, &new, as_id, change);
+	r = kvm_set_memslot(kvm, mem, &new, change);
 	if (r)
 		goto out_bitmap;
 
