On Thu, Jul 18, 2024 at 03:33:25PM +0800, Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> wrote: > > > > + > > > > + memcpy(&val, vcpu->run->mmio.data, size); > > > > + tdvmcall_set_return_val(vcpu, val); > > > > + trace_kvm_mmio(KVM_TRACE_MMIO_READ, size, gpa, &val); > > > > + } > > > Tracepoint for KVM_TRACE_MMIO_WRITE is missing when it is handled in > > > userspace. > > tdx_mmio_write() has it before existing to the user space. It matches with > > how write_mmio() behaves in x86.c. > > > > Hmm, to match with other code, we should remove > > trace_kvm_mmio(KVM_TRACE_MMIO_READ) and keep KVM_TRACE_MMIO_READ_UNSATISFIED > > in tdx_emulate_mmio(). That's how read_prepare() and read_exit_mmio() behaves. > > > > For MMIO read > > - When kernel can handle the MMIO, KVM_TRACE_MMIO_READ with data. > > - When exiting to the user space, KVM_TRACE_MMIO_READ_UNSATISFIED before > > the exit. No trace after the user space handled the MMIO. > > For MMIO read, in the emulator, there is still a trace after the userspace > handled the MMIO. > In complete_emulated_mmio(), if all fragments have been handled, it will > set vcpu->mmio_read_completed to 1 and call complete_emulated_io(). > complete_emulated_io > kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE) > x86_emulate_instruction > x86_emulate_insn > emulator_read_write > read_prepare > At this point, vcpu->mmio_read_completed is 1, > it traces KVM_TRACE_MMIO_READ with data > and then clear vcpu->mmio_read_completed > > So to align with emulator, we should keep the trace for KVM_TRACE_MMIO_READ. Oops, you're right. Agreed to keep it. -- Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
