RE: [Xen-devel] [PATCH 08/16] vmx: nest: vmresume/vmlaunch

["Dong, Eddie" <eddie.dong@xxxxxxxxx>]

Christoph Egger wrote:
> On Wednesday 15 September 2010 11:52:26 Christoph Egger wrote:
>> On Wednesday 08 September 2010 17:22:16 Qing He wrote:
>>> vmresume and vmlaunch instructions and transitional states
>>> 
>>> Signed-off-by: Qing He <qing.he@xxxxxxxxx>
>>> Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>
>>> 
>>> ---
>>> 
>>> diff -r e828d55c10bb xen/arch/x86/hvm/vmx/nest.c
>>> --- a/xen/arch/x86/hvm/vmx/nest.c   Wed Sep 08 21:42:10 2010 +0800
>>> +++ b/xen/arch/x86/hvm/vmx/nest.c   Wed Sep 08 22:04:16 2010 +0800 @@
>>>      -633,3 +633,33 @@ hvm_inject_exception(TRAP_invalid_op, 0, 0);
>>>      return X86EMUL_EXCEPTION;
>>>  }
>>> +
>>> +int vmx_nest_handle_vmresume(struct cpu_user_regs *regs) +{
>>> +    struct vcpu *v = current;
>>> +    struct vmx_nest_struct *nest = &v->arch.hvm_vmx.nest; +    int
>>> rc; +
>>> +    if ( unlikely(!nest->guest_vmxon_pa) )
>>> +        goto invalid_op;
>>> +
>>> +    rc = vmx_inst_check_privilege(regs);
>>> +    if ( rc != X86EMUL_OKAY )
>>> +        return rc;
>>> +
>>> +    if ( nest->vmcs_valid == 1 )
>>> +        nest->vmresume_pending = 1;
>>> +    else
>>> +        vmreturn(regs, VMFAIL_INVALID);
>>> +
>>> +    return X86EMUL_OKAY;
>>> +
>>> +invalid_op:
>>> +    hvm_inject_exception(TRAP_invalid_op, 0, 0);
>>> +    return X86EMUL_EXCEPTION;
>>> +}
>>> +
>>> +int vmx_nest_handle_vmlaunch(struct cpu_user_regs *regs) +{
>>> +    return vmx_nest_handle_vmresume(regs);
>>> +}
>>> diff -r e828d55c10bb xen/arch/x86/hvm/vmx/vmx.c
>>> --- a/xen/arch/x86/hvm/vmx/vmx.c    Wed Sep 08 21:42:10 2010 +0800
>>> +++ b/xen/arch/x86/hvm/vmx/vmx.c    Wed Sep 08 22:04:16 2010 +0800 @@
>>>      -2321,6 +2321,11 @@ /* Now enable interrupts so it's safe to
>>> take locks. */      local_irq_enable(); 
>>> 
>>> +    /* XXX: This looks ugly, but we need a mechanism to ensure
>>> +     * any pending vmresume has really happened
>>> +     */
>>> +    v->arch.hvm_vmx.nest.vmresume_in_progress = 0; +
>>>      if ( unlikely(exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) )
>>>          return vmx_failed_vmentry(exit_reason, regs);
>>> 
>>> @@ -2592,6 +2597,11 @@
>>>          if ( vmx_nest_handle_vmclear(regs) == X86EMUL_OKAY )
>>>              __update_guest_eip(inst_len);
>>>          break;
>>> +    case EXIT_REASON_VMLAUNCH:
>>> +        inst_len = __get_instruction_length();
>>> +        if ( vmx_nest_handle_vmlaunch(regs) == X86EMUL_OKAY )
>>> +            __update_guest_eip(inst_len);
>>> +        break;
>>>      case EXIT_REASON_VMPTRLD:
>>>          inst_len = __get_instruction_length();
>>>          if ( vmx_nest_handle_vmptrld(regs) == X86EMUL_OKAY ) @@
>>>          -2607,6 +2617,11 @@ if ( vmx_nest_handle_vmread(regs) ==
>>>              X86EMUL_OKAY ) __update_guest_eip(inst_len);
>>>          break;
>>> +    case EXIT_REASON_VMRESUME:
>>> +        inst_len = __get_instruction_length();
>>> +        if ( vmx_nest_handle_vmresume(regs) == X86EMUL_OKAY )
>>> +            __update_guest_eip(inst_len);
>>> +        break;
>>>      case EXIT_REASON_VMWRITE:
>>>          inst_len = __get_instruction_length();
>>>          if ( vmx_nest_handle_vmwrite(regs) == X86EMUL_OKAY ) @@
>>> -2625,8 +2640,6 @@ 
>>> 
>>>      case EXIT_REASON_MWAIT_INSTRUCTION:
>>>      case EXIT_REASON_MONITOR_INSTRUCTION:
>>> -    case EXIT_REASON_VMLAUNCH:
>>> -    case EXIT_REASON_VMRESUME:
>>>          vmx_inject_hw_exception(TRAP_invalid_op,
>>> HVM_DELIVER_NO_ERROR_CODE); break;
>>> 
>>> diff -r e828d55c10bb xen/include/asm-x86/hvm/vmx/nest.h
>>> --- a/xen/include/asm-x86/hvm/vmx/nest.h    Wed Sep 08 21:42:10 2010
>>> +0800 +++ b/xen/include/asm-x86/hvm/vmx/nest.h      Wed Sep 08 22:04:16
>>>      2010 +0800 @@ -40,6 +40,20 @@ void                *vvmcs;
>>>      struct vmcs_struct  *svmcs;
>>>      int                  vmcs_valid;
>>> +
>>> +    /*
>>> +     * vmexit_pending and vmresume_pending is to mark pending
>>> +     * switches, they are cleared when physical vmcs is changed. +
>>> */ +    int                  vmexit_pending;
>>> +    int                  vmresume_pending;
>> 
>> This is functional equal to the vmentry flag in struct nestedhvm.
> 
> Is it possible to have both vmexit and vmresume pending at the same
> time ? 
> 

Should not be. We may be able to use single variable for multiple state.
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