Re: [Xen-devel] [PATCH v3] x86/mce: handle reserved domain ID in XEN_MC_msrinject

["Egger, Christoph" <chegger@xxxxxxxxx>]

On 27.05.16 15:30, Haozhong Zhang wrote:
> Commit 26646f3 "x86/mce: translate passed-in GPA to host machine
> address" and commit 4ddf474 "tools/xen-mceinj: Pass in GPA when
> injecting through MSR_MCI_ADDR" forgot to consider reserved domain
> ID and mistakenly add MC_MSRINJ_F_GPADDR flag for them, which in turn
> causes bug reported by
> http://lists.xenproject.org/archives/html/xen-devel/2016-05/msg02640.html.
> 
> This patch removes MC_MSRINK_F_GPADDR flag and checks this when injecting
> to reserved domain IDs except DOMID_SELF, and treats the passed-in
> address as host machine address.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>

Acked-by: Christoph Egger <chegger@xxxxxxxxx>

> ---
> Changes in v3:
>  * Refine check condition of domid.
> 
> Changes in v2:
>  * Consider all reserved domain IDs rather than just DOMID_XEN.
> 
> v1 can be found at
> http://lists.xenproject.org/archives/html/xen-devel/2016-05/msg02534.html.
> ---
>  tools/tests/mce-test/tools/xen-mceinj.c |  5 ++++-
>  xen/arch/x86/cpu/mcheck/mce.c           | 14 +++++++++++---
>  2 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/tests/mce-test/tools/xen-mceinj.c 
> b/tools/tests/mce-test/tools/xen-mceinj.c
> index 061ec7c..51abc8a 100644
> --- a/tools/tests/mce-test/tools/xen-mceinj.c
> +++ b/tools/tests/mce-test/tools/xen-mceinj.c
> @@ -317,7 +317,10 @@ static int inject_mci_addr(xc_interface *xc_handle,
>                             domid_t domid)
>  {
>      return add_msr_bank_intpose(xc_handle, cpu_nr,
> -                                MC_MSRINJ_F_INTERPOSE | MC_MSRINJ_F_GPADDR,
> +                                MC_MSRINJ_F_INTERPOSE |
> +                                ((domid >= DOMID_FIRST_RESERVED &&
> +                                  domid != DOMID_SELF) ?
> +                                 0 : MC_MSRINJ_F_GPADDR),
>                                  MCi_type_ADDR, bank, val, domid);
>  }
>  
> diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
> index cc446eb..0244553 100644
> --- a/xen/arch/x86/cpu/mcheck/mce.c
> +++ b/xen/arch/x86/cpu/mcheck/mce.c
> @@ -1427,6 +1427,7 @@ long do_mca(XEN_GUEST_HANDLE_PARAM(xen_mc_t) u_xen_mc)
>  
>          if ( mc_msrinject->mcinj_flags & MC_MSRINJ_F_GPADDR )
>          {
> +            domid_t domid;
>              struct domain *d;
>              struct mcinfo_msr *msr;
>              unsigned int i;
> @@ -1434,10 +1435,17 @@ long do_mca(XEN_GUEST_HANDLE_PARAM(xen_mc_t) u_xen_mc)
>              unsigned long gfn, mfn;
>              p2m_type_t t;
>  
> -            d = get_domain_by_id(mc_msrinject->mcinj_domid);
> +            domid = (mc_msrinject->mcinj_domid == DOMID_SELF) ?
> +                    current->domain->domain_id : mc_msrinject->mcinj_domid;
> +            if ( domid >= DOMID_FIRST_RESERVED )
> +                return x86_mcerr("do_mca inject: incompatible flag "
> +                                 "MC_MSRINJ_F_GPADDR with domain %d",
> +                                 -EINVAL, domid);
> +
> +            d = get_domain_by_id(domid);
>              if ( d == NULL )
>                  return x86_mcerr("do_mca inject: bad domain id %d",
> -                                 -EINVAL, mc_msrinject->mcinj_domid);
> +                                 -EINVAL, domid);
>  
>              for ( i = 0, msr = &mc_msrinject->mcinj_msr[0];
>                    i < mc_msrinject->mcinj_count;
> @@ -1452,7 +1460,7 @@ long do_mca(XEN_GUEST_HANDLE_PARAM(xen_mc_t) u_xen_mc)
>                      put_gfn(d, gfn);
>                      put_domain(d);
>                      return x86_mcerr("do_mca inject: bad gfn %#lx of domain 
> %d",
> -                                     -EINVAL, gfn, 
> mc_msrinject->mcinj_domid);
> +                                     -EINVAL, gfn, domid);
>                  }
>  
>                  msr->value = pfn_to_paddr(mfn) | (gaddr & (PAGE_SIZE - 1));
> 


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