On 2/29/2024 14:36, Xiaoyao Li wrote:> 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;
kvm_check_extension() only returns non-negative value, so we can just
kvm_supported_memory_attributes = kvm_check_extension(s, KVM_CAP_MEMORY_ATTRIBUTES);
> +
> 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
