Re: [Xen-devel] [PATCH v1 4/6] x86/vvmx: add VMX_INSN_VMCLEAR_WITH_VMXON_PTR errno

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Sergey Dyasli [mailto:sergey.dyasli@xxxxxxxxxx]
> Sent: Friday, October 12, 2018 11:28 PM
> 
> And make nvmx_handle_vmclear() return the new errno in case the
> provided
> address is the same as vmxon region address.
> 
> While at it, correct the return value for not-4KB-aligned case and for
> invalid physaddr.
> 
> Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
> ---
>  xen/arch/x86/hvm/vmx/vvmx.c        | 23 ++++++++++++++++++-----
>  xen/include/asm-x86/hvm/vmx/vmcs.h |  1 +
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/vmx/vvmx.c
> b/xen/arch/x86/hvm/vmx/vvmx.c
> index 4caa5811a1..8b691bfc04 100644
> --- a/xen/arch/x86/hvm/vmx/vvmx.c
> +++ b/xen/arch/x86/hvm/vmx/vvmx.c
> @@ -1804,9 +1804,20 @@ int nvmx_handle_vmclear(struct cpu_user_regs
> *regs)
>          return rc;
> 
>      BUILD_BUG_ON(X86EMUL_OKAY != VMSUCCEED); /* rc = VMSUCCEED;
> */
> +
> +    if ( gpa == vcpu_2_nvmx(v).vmxon_region_pa )
> +    {
> +        vmfail(regs, VMX_INSN_VMCLEAR_WITH_VMXON_PTR);
> +        goto out;
> +    }
> +
>      if ( gpa & 0xfff )
> -        rc = VMFAIL_INVALID;
> -    else if ( gpa == nvcpu->nv_vvmcxaddr )
> +    {
> +        vmfail(regs, VMX_INSN_VMCLEAR_INVALID_PHYADDR);
> +        goto out;
> +    }
> +
> +    if ( gpa == nvcpu->nv_vvmcxaddr )
>      {
>          if ( cpu_has_vmx_vmcs_shadowing )
>              nvmx_clear_vmcs_pointer(v, nvcpu->nv_vvmcx);
> @@ -1820,7 +1831,10 @@ int nvmx_handle_vmclear(struct cpu_user_regs
> *regs)
>          bool_t writable;
> 
>          vvmcs = hvm_map_guest_frame_rw(paddr_to_pfn(gpa), 0, &writable);
> -        if ( vvmcs )
> +
> +        if ( !vvmcs )
> +            rc = VMFAIL_VALID;
> +        else
>          {
>              if ( writable )
>                  clear_vvmcs_launched(&nvmx->launched_list,
> @@ -1835,9 +1849,8 @@ int nvmx_handle_vmclear(struct cpu_user_regs
> *regs)
>          vmsucceed(regs);
>      else if ( rc == VMFAIL_VALID )
>          vmfail(regs, VMX_INSN_VMCLEAR_INVALID_PHYADDR);
> -    else
> -        vmfail_invalid(regs);
> 

there is only one place poking rc now. clearer to replace rc with direct
vmfail too. then above rc checks can be removed.

> +out:
>      return X86EMUL_OKAY;
>  }
> 
> diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-
> x86/hvm/vmx/vmcs.h
> index cae1861610..e84d2e482b 100644
> --- a/xen/include/asm-x86/hvm/vmx/vmcs.h
> +++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
> @@ -529,6 +529,7 @@ enum vmx_insn_errno
>  {
>      VMX_INSN_SUCCEED                       = 0,
>      VMX_INSN_VMCLEAR_INVALID_PHYADDR       = 2,
> +    VMX_INSN_VMCLEAR_WITH_VMXON_PTR        = 3,
>      VMX_INSN_VMLAUNCH_NONCLEAR_VMCS        = 4,
>      VMX_INSN_VMRESUME_NONLAUNCHED_VMCS     = 5,
>      VMX_INSN_INVALID_CONTROL_STATE         = 7,
> --
> 2.17.1


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