Re: [PATCH v2 3/4] x86/mce: Translate passed-in GPA to host machine address

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

On 2015/09/16 7:35, 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>

Acked-by: Christoph Egger <chegger@amazon.de>

> ---
>  xen/arch/x86/cpu/mcheck/mce.c         | 56 ++++++++++++++++++++++++++++++-----
>  xen/include/public/arch-x86/xen-mca.h |  5 +++-
>  2 files changed, 52 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
> index 561257d..08cd3f2 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"
> @@ -48,14 +49,15 @@ struct mca_banks *mca_allbanks;
>  #define _MC_MSRINJ_F_REQ_HWCR_WREN (1 << 16)
>  
>  #if 0
> -static int x86_mcerr(const char *msg, int err)
> -{
> -    gdprintk(XENLOG_WARNING, "x86_mcerr: %s, returning %d\n",
> -             msg != NULL ? msg : "", err);
> -    return err;
> -}
> +#define x86_mcerr(fmt, err, args...)                                    \
> +    ({                                                                  \
> +        int _err = (err);                                               \
> +        gdprintk(XENLOG_WARNING, "x86_mcerr: " fmt ", returning %d\n",  \
> +                 ## args, _err);                                        \
> +        _err;                                                           \
> +    })
>  #else
> -#define x86_mcerr(msg, err) (err)
> +#define x86_mcerr(fmt, err, args...) (err)
>  #endif
>  
>  int mce_verbosity;
> @@ -1307,7 +1309,7 @@ long do_mca(XEN_GUEST_HANDLE_PARAM(xen_mc_t) u_xen_mc)
>  
>      ret = xsm_do_mca(XSM_PRIV);
>      if ( ret )
> -        return x86_mcerr(NULL, ret);
> +        return x86_mcerr("", ret);
>  
>      if ( copy_from_guest(op, u_xen_mc, 1) )
>          return x86_mcerr("do_mca: failed copyin of xen_mc_t", -EFAULT);
> @@ -1422,6 +1424,44 @@ 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;
> +            unsigned int i;
> +            paddr_t gaddr;
> +            unsigned long gfn, mfn;
> +            p2m_type_t t;
> +
> +            d = get_domain_by_id(mc_msrinject->mcinj_domid);
> +            if ( d == NULL )
> +                return x86_mcerr("do_mca inject: bad domain id %d",
> +                                 -EINVAL, mc_msrinject->mcinj_domid);
> +
> +            for ( i = 0, msr = &mc_msrinject->mcinj_msr[0];
> +                  i < mc_msrinject->mcinj_count;
> +                  i++, msr++ )
> +            {
> +                gaddr = msr->value;
> +                gfn = PFN_DOWN(gaddr);
> +                mfn = mfn_x(get_gfn(d, gfn, &t));
> +
> +                if ( mfn == INVALID_MFN )
> +                {
> +                    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);
> +                }
> +
> +                msr->value = pfn_to_paddr(mfn) | (gaddr & (PAGE_SIZE - 1));
> +
> +                put_gfn(d, gfn);
> +            }
> +
> +            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 ec1237a..a97e821 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 is
> +                                       present in mcinj_flags */
> +    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 {
> 

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