On 2023-07-31 at 12:21:57 -0400, Xiaoyao Li wrote:
> From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
>
> Currently only KVM_MEMORY_EXIT_FLAG_PRIVATE in flags is valid when
> KVM_EXIT_MEMORY_FAULT happens. It indicates userspace needs to do
> the memory conversion on the RAMBlock to turn the memory into desired
> attribute, i.e., private/shared.
>
> Note, KVM_EXIT_MEMORY_FAULT makes sense only when the RAMBlock has
> gmem memory backend.
>
> Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> ---
> accel/kvm/kvm-all.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 52 insertions(+)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index f9b5050b8885..72d50b923bf2 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -3040,6 +3040,48 @@ static void kvm_eat_signals(CPUState *cpu)
> } while (sigismember(&chkset, SIG_IPI));
> }
>
> +static int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private)
> +{
> + MemoryRegionSection section;
> + void *addr;
> + RAMBlock *rb;
> + ram_addr_t offset;
> + int ret = -1;
> +
> + section = memory_region_find(get_system_memory(), start, size);
> + if (!section.mr) {
> + return ret;
> + }
> +
> + if (memory_region_can_be_private(section.mr)) {
> + if (to_private) {
> + ret = kvm_set_memory_attributes_private(start, size);
> + } else {
> + ret = kvm_set_memory_attributes_shared(start, size);
> + }
> +
> + if (ret) {
> + return ret;
Should we unref the memory region before return?
Thanks,
Yilun
> + }
> +
> + addr = memory_region_get_ram_ptr(section.mr) +
> + section.offset_within_region;
> + rb = qemu_ram_block_from_host(addr, false, &offset);
> + /*
> + * With KVM_SET_MEMORY_ATTRIBUTES by kvm_set_memory_attributes(),
> + * operation on underlying file descriptor is only for releasing
> + * unnecessary pages.
> + */
> + ram_block_convert_range(rb, offset, size, to_private);
> + } else {
> + warn_report("Convert non guest-memfd backed memory region (0x%"HWADDR_PRIx" ,+ 0x%"HWADDR_PRIx") to %s",
> + start, size, to_private ? "private" : "shared");
> + }
> +
> + memory_region_unref(section.mr);
> + return ret;
> +}
