[PATCH v5 06/65] kvm: Introduce support for memory_attributes

[Xiaoyao Li <xiaoyao.li@xxxxxxxxx>]

Introduce the helper functions to set the attributes of a range of
memory to private or shared.

This is necessary to notify KVM the private/shared attribute of each gpa
range. KVM needs the information to decide the GPA needs to be mapped at
hva-based shared memory or guest_memfd based private memory.

Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
Changes in v4:
- move the check of kvm_supported_memory_attributes to the common
  kvm_set_memory_attributes(); (Wang Wei)
- change warn_report() to error_report() in kvm_set_memory_attributes()
  and drop the __func__; (Daniel)
---
 accel/kvm/kvm-all.c  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 include/sysemu/kvm.h |  3 +++
 2 files changed, 47 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index cd0aa7545a1f..70d482a2c936 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -92,6 +92,7 @@ static bool kvm_has_guest_debug;
 static int kvm_sstep_flags;
 static bool kvm_immediate_exit;
 static bool kvm_guest_memfd_supported;
+static uint64_t kvm_supported_memory_attributes;
 static hwaddr kvm_max_slot_size = ~0;
 
 static const KVMCapabilityInfo kvm_required_capabilites[] = {
@@ -1304,6 +1305,46 @@ void kvm_set_max_memslot_size(hwaddr max_slot_size)
     kvm_max_slot_size = max_slot_size;
 }
 
+static int kvm_set_memory_attributes(hwaddr start, hwaddr size, uint64_t attr)
+{
+    struct kvm_memory_attributes attrs;
+    int r;
+
+    if (kvm_supported_memory_attributes == 0) {
+        error_report("No memory attribute supported by KVM\n");
+        return -EINVAL;
+    }
+
+    if ((attr & kvm_supported_memory_attributes) != attr) {
+        error_report("memory attribute 0x%lx not supported by KVM,"
+                     " supported bits are 0x%lx\n",
+                     attr, kvm_supported_memory_attributes);
+        return -EINVAL;
+    }
+
+    attrs.attributes = attr;
+    attrs.address = start;
+    attrs.size = size;
+    attrs.flags = 0;
+
+    r = kvm_vm_ioctl(kvm_state, KVM_SET_MEMORY_ATTRIBUTES, &attrs);
+    if (r) {
+        error_report("failed to set memory (0x%lx+%#zx) with attr 0x%lx error '%s'",
+                     start, size, attr, strerror(errno));
+    }
+    return r;
+}
+
+int kvm_set_memory_attributes_private(hwaddr start, hwaddr size)
+{
+    return kvm_set_memory_attributes(start, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
+int kvm_set_memory_attributes_shared(hwaddr start, hwaddr size)
+{
+    return kvm_set_memory_attributes(start, size, 0);
+}
+
 /* Called with KVMMemoryListener.slots_lock held */
 static void kvm_set_phys_mem(KVMMemoryListener *kml,
                              MemoryRegionSection *section, bool add)
@@ -2439,6 +2480,9 @@ static int kvm_init(MachineState *ms)
 
     kvm_guest_memfd_supported = kvm_check_extension(s, KVM_CAP_GUEST_MEMFD);
 
+    ret = kvm_check_extension(s, KVM_CAP_MEMORY_ATTRIBUTES);
+    kvm_supported_memory_attributes = ret > 0 ? ret : 0;
+
     if (object_property_find(OBJECT(current_machine), "kvm-type")) {
         g_autofree char *kvm_type = object_property_get_str(OBJECT(current_machine),
                                                             "kvm-type",
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 6cdf82de8372..8e83adfbbd19 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -546,4 +546,7 @@ uint32_t kvm_dirty_ring_size(void);
 bool kvm_hwpoisoned_mem(void);
 
 int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp);
+
+int kvm_set_memory_attributes_private(hwaddr start, hwaddr size);
+int kvm_set_memory_attributes_shared(hwaddr start, hwaddr size);
 #endif
-- 
2.34.1