[PATCH v3 06/70] kvm: Introduce support for memory_attributes

Xiaoyao Li
2023-11-15T07:16:28Z

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@intel.com>
---
accel/kvm/kvm-all.c | 42 ++++++++++++++++++++++++++++++++++++++++++
include/sysemu/kvm.h | 3 +++
2 files changed, 45 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 69afeb47c9c0..76e2404d54d2 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -102,6 +102,7 @@ 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[] = {
@@ -1305,6 +1306,44 @@ 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;
+
+ 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) {
+ warn_report("%s: failed to set memory (0x%lx+%#zx) with attr 0x%lx error '%s'",
+ __func__, start, size, attr, strerror(errno));
+ }
+ return r;
+}
+
+int kvm_set_memory_attributes_private(hwaddr start, hwaddr size)
+{
+ if (!(kvm_supported_memory_attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
+ error_report("KVM doesn't support PRIVATE memory attribute\n");
+ return -EINVAL;
+ }
+
+ return kvm_set_memory_attributes(start, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
+int kvm_set_memory_attributes_shared(hwaddr start, hwaddr size)
+{
+ if (!(kvm_supported_memory_attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
+ error_report("KVM doesn't support PRIVATE memory attribute\n");
+ return -EINVAL;
+ }
+
+ 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)
@@ -2440,6 +2479,9 @@ 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 fedc28c7d17f..0e88958190a4 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -540,4 +540,7 @@ bool kvm_dirty_ring_enabled(void);
uint32_t kvm_dirty_ring_size(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