linux-kernel - [RFC 22/33] KVM: Decouple kvm_ioctl_set_mem_attributes() from kvm's mem_attr

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Message-ID: <20231108111806.92604-23-nsaenz@amazon.com>
Date:   Wed, 8 Nov 2023 11:17:55 +0000
From:   Nicolas Saenz Julienne <nsaenz@...zon.com>
To:     <kvm@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-hyperv@...r.kernel.org>,
        <pbonzini@...hat.com>, <seanjc@...gle.com>, <vkuznets@...hat.com>,
        <anelkz@...zon.com>, <graf@...zon.com>, <dwmw@...zon.co.uk>,
        <jgowans@...zon.com>, <corbert@....net>, <kys@...rosoft.com>,
        <haiyangz@...rosoft.com>, <decui@...rosoft.com>, <x86@...nel.org>,
        <linux-doc@...r.kernel.org>,
        Nicolas Saenz Julienne <nsaenz@...zon.com>
Subject: [RFC 22/33] KVM: Decouple kvm_ioctl_set_mem_attributes() from kvm's mem_attr_array

VSM will keep track of each VTL's memory protections in a separate
mem_attr_array. Access to these arrays will happen by issuing
KVM_SET_MEMORY_ATTRIBUTES ioctls to their respective KVM VTL devices
(which is also introduced in subsequent patches). Let the VTL devices
reuse kvm_ioctl_set_mem_attributes() by decoupling it from struct kvm's
mem_attr_array. The xarray is now input as a function argument as well
as the list of supported memory attributes.

Signed-off-by: Nicolas Saenz Julienne <nsaenz@...zon.com>
---
 include/linux/kvm_host.h |  3 +++
 virt/kvm/kvm_main.c      | 32 ++++++++++++++++++++++----------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 652656444c45..ad104794037f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2394,6 +2394,9 @@ kvm_get_memory_attributes(struct xarray *mem_attr_array, gfn_t gfn)
 	return xa_to_value(xa_load(mem_attr_array, gfn));
 }
 
+int kvm_ioctl_set_mem_attributes(struct kvm *kvm, struct xarray *mem_attr_array,
+				 u64 supported_attrs,
+				 struct kvm_memory_attributes *attrs);
 bool kvm_range_has_memory_attributes(struct xarray *mem_attr_array, gfn_t start,
 				     gfn_t end, unsigned long attrs);
 bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f20dafaedc72..74c4c42b2126 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2554,8 +2554,9 @@ static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
 }
 
 /* Set @attributes for the gfn range [@start, @end). */
-static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
-				     unsigned long attributes)
+static int kvm_set_mem_attributes(struct kvm *kvm,
+				  struct xarray *mem_attr_array, gfn_t start,
+				  gfn_t end, unsigned long attributes)
 {
 	struct kvm_mmu_notifier_range pre_set_range = {
 		.start = start,
@@ -2569,7 +2570,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 		.start = start,
 		.end = end,
 		.arg.attributes = attributes,
-		.arg.mem_attr_array = &kvm->mem_attr_array,
+		.arg.mem_attr_array = mem_attr_array,
 		.handler = kvm_arch_post_set_memory_attributes,
 		.on_lock = kvm_mmu_invalidate_end,
 		.may_block = true,
@@ -2583,7 +2584,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 	mutex_lock(&kvm->slots_lock);
 
 	/* Nothing to do if the entire range as the desired attributes. */
-	if (kvm_range_has_memory_attributes(&kvm->mem_attr_array, start, end,
+	if (kvm_range_has_memory_attributes(mem_attr_array, start, end,
 					    attributes))
 		goto out_unlock;
 
@@ -2592,7 +2593,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 	 * partway through setting the new attributes.
 	 */
 	for (i = start; i < end; i++) {
-		r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT);
+		r = xa_reserve(mem_attr_array, i, GFP_KERNEL_ACCOUNT);
 		if (r)
 			goto out_unlock;
 	}
@@ -2600,7 +2601,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 	kvm_handle_gfn_range(kvm, &pre_set_range);
 
 	for (i = start; i < end; i++) {
-		r = xa_err(xa_store(&kvm->mem_attr_array, i, entry,
+		r = xa_err(xa_store(mem_attr_array, i, entry,
 				    GFP_KERNEL_ACCOUNT));
 		KVM_BUG_ON(r, kvm);
 	}
@@ -2612,15 +2613,17 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 
 	return r;
 }
-static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
-					   struct kvm_memory_attributes *attrs)
+
+int kvm_ioctl_set_mem_attributes(struct kvm *kvm, struct xarray *mem_attr_array,
+				 u64 supported_attrs,
+				 struct kvm_memory_attributes *attrs)
 {
 	gfn_t start, end;
 
 	/* flags is currently not used. */
 	if (attrs->flags)
 		return -EINVAL;
-	if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
+	if (attrs->attributes & ~supported_attrs)
 		return -EINVAL;
 	if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
 		return -EINVAL;
@@ -2637,7 +2640,16 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	 */
 	BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long));
 
-	return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
+	return kvm_set_mem_attributes(kvm, mem_attr_array, start, end,
+				      attrs->attributes);
+}
+
+static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
+					   struct kvm_memory_attributes *attrs)
+{
+	return kvm_ioctl_set_mem_attributes(kvm, &kvm->mem_attr_array,
+					    kvm_supported_mem_attributes(kvm),
+					    attrs);
 }
 #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
 
-- 
2.40.1