On 8/9/2023 11:02 PM, Xu Yilun wrote:
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 for catching this!
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; +}
