Re: [PATCH 3/4] x86/mce: Translate passed-in GPA to host machine address

["Egger, Christoph" <chegger@amazon.de>]

On 2015/09/15 10:29, Haozhong Zhang wrote:
> This patch adds a new flag MC_MSRINJ_F_GPADDR to
> xen_mc_msrinject.mcinj_flags, and makes do_mca() to translate the
> guest physical address passed-in through
> xen_mc_msrinject.mcinj_msr[i].value to the host machine address if
> this flag is present.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>

Comments inline.

> ---
>  xen/arch/x86/cpu/mcheck/mce.c         | 33 +++++++++++++++++++++++++++++++++
>  xen/include/public/arch-x86/xen-mca.h |  5 ++++-
>  2 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
> index 561257d..343d9d2 100644
> --- a/xen/arch/x86/cpu/mcheck/mce.c
> +++ b/xen/arch/x86/cpu/mcheck/mce.c
> @@ -21,6 +21,7 @@
>  #include <asm/processor.h>
>  #include <asm/system.h>
>  #include <asm/msr.h>
> +#include <asm/p2m.h>
>  
>  #include "mce.h"
>  #include "barrier.h"
> @@ -1422,6 +1423,38 @@ long do_mca(XEN_GUEST_HANDLE_PARAM(xen_mc_t) u_xen_mc)
>          if (mc_msrinject->mcinj_count == 0)
>              return 0;
>  
> +        if (mc_msrinject->mcinj_flags & MC_MSRINJ_F_GPADDR) {
> +            struct domain *d;
> +            struct mcinfo_msr *msr;
> +            int i;
> +            uint64_t gaddr, gpfn, mfn, haddr;
> +            p2m_type_t t;
> +
> +            d = get_domain_by_id(mc_msrinject->mcinj_domid);
> +            if (d == NULL)
> +                return x86_mcerr("do_mca inject: illegal domain id", -EINVAL);
> +
> +            for (i = 0, msr = &mc_msrinject->mcinj_msr[0];
> +                 i < mc_msrinject->mcinj_count; i++, msr++) {
> +                gaddr = msr->value;
> +                gpfn = gaddr >> PAGE_SHIFT;
> +                mfn = mfn_x(get_gfn(d, gpfn, &t));
> +
> +                if (mfn == INVALID_MFN) {

                       put_gfn(d, gpfn);

> +                    put_domain(d);
> +                    return x86_mcerr("do_mca inject: illegal MSR value",
> +                                     -EINVAL);
> +                }
> +
> +                haddr = (mfn << PAGE_SHIFT) | (gaddr & (PAGE_SIZE - 1));
> +                msr->value = haddr;
> +
> +                put_gfn(d, gpfn);
> +            }
> +
> +            put_domain(d);
> +        }
> +
>          if (!x86_mc_msrinject_verify(mc_msrinject))
>              return x86_mcerr("do_mca inject: illegal MSR", -EINVAL);
>  
> diff --git a/xen/include/public/arch-x86/xen-mca.h b/xen/include/public/arch-x86/xen-mca.h
> index 2422b76..33c1a84 100644
> --- a/xen/include/public/arch-x86/xen-mca.h
> +++ b/xen/include/public/arch-x86/xen-mca.h
> @@ -392,12 +392,15 @@ struct xen_mc_msrinject {
>      uint32_t mcinj_cpunr;           /* target processor id */
>      uint32_t mcinj_flags;           /* see MC_MSRINJ_F_* below */
>      uint32_t mcinj_count;           /* 0 .. count-1 in array are valid */
> -    uint32_t _pad0;
> +    domid_t  mcinj_domid;           /* valid only if MC_MSRINJ_F_GPADDR presents
> +                                       in mcinj_flags */

wording. I prefer "s/presents/is present/"

> +    uint16_t _pad0;
>      struct mcinfo_msr mcinj_msr[MC_MSRINJ_MAXMSRS];
>  };
>  
>  /* Flags for mcinj_flags above; bits 16-31 are reserved */
>  #define MC_MSRINJ_F_INTERPOSE   0x1
> +#define MC_MSRINJ_F_GPADDR      0x2
>  
>  #define XEN_MC_mceinject    5
>  struct xen_mc_mceinject {
> 

Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrer: Dr. Ralf Herbrich, Christian Schlaeger
Ust-ID: DE289237879
Eingetragen am Amtsgericht Charlottenburg HRB 149173 B