Re: [Xen-devel] [PATCH 5/5] X86/vMCE: guest broken page handling when migration

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2012-09-19 at 09:15 +0100, Liu, Jinsong wrote:
> X86/vMCE: guest broken page handling when migration
> 
> This patch is used to handle guest broken page when migration.
> 
> At sender, the broken page would not be mapped, and the error page
> content would not be copied to target, otherwise it may trigger more
> serious error (i.e. SRAR error). While its pfn_type and pfn number
> would be transferred to target so that target take appropriate action.
> 
> At target, it would set p2m as p2m_ram_broken for broken page, so that
> if guest access the broken page again, it would kill guest as expected.
> 
> Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> 
> diff -r a1d106d1aec8 tools/libxc/xc_domain.c
> --- a/tools/libxc/xc_domain.c Wed Sep 19 03:31:31 2012 +0800
> +++ b/tools/libxc/xc_domain.c Wed Sep 19 04:22:26 2012 +0800
> @@ -314,6 +314,22 @@
>      return ret ? -1 : 0;
>  }
>  
> +/* set broken page p2m */
> +int xc_set_broken_page_p2m(xc_interface *xch,
> +                           uint32_t domid,
> +                           unsigned long pfn)
> +{
> +    int ret;
> +    DECLARE_DOMCTL;
> +
> +    domctl.cmd = XEN_DOMCTL_set_broken_page_p2m;
> +    domctl.domain = (domid_t)domid;
> +    domctl.u.set_broken_page_p2m.pfn = pfn;
> +    ret = do_domctl(xch, &domctl);
> +
> +    return ret ? -1 : 0;
> +}
> +
>  /* get info from hvm guest for save */
>  int xc_domain_hvm_getcontext(xc_interface *xch,
>                               uint32_t domid,
> diff -r a1d106d1aec8 tools/libxc/xc_domain_restore.c
> --- a/tools/libxc/xc_domain_restore.c Wed Sep 19 03:31:31 2012 +0800
> +++ b/tools/libxc/xc_domain_restore.c Wed Sep 19 04:22:26 2012 +0800
> @@ -962,9 +962,15 @@
>  
>      countpages = count;
>      for (i = oldcount; i < buf->nr_pages; ++i)
> -        if ((buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == 
> XEN_DOMCTL_PFINFO_XTAB
> -            ||(buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) == 
> XEN_DOMCTL_PFINFO_XALLOC)
> +    {
> +        unsigned long pagetype;
> +
> +        pagetype = buf->pfn_types[i] & XEN_DOMCTL_PFINFO_LTAB_MASK;
> +        if ( pagetype == XEN_DOMCTL_PFINFO_XTAB ||
> +             pagetype == XEN_DOMCTL_PFINFO_BROKEN ||
> +             pagetype == XEN_DOMCTL_PFINFO_XALLOC )
>              --countpages;
> +    }
>  
>      if (!countpages)
>          return count;
> @@ -1200,6 +1206,17 @@
>              /* a bogus/unmapped/allocate-only page: skip it */
>              continue;
>  
> +        if ( pagetype == XEN_DOMCTL_PFINFO_BROKEN )
> +        {
> +            if ( xc_set_broken_page_p2m(xch, dom, pfn) )
> +            {
> +                ERROR("Set p2m for broken page fail, "

"failed"

> +                      "dom=%d, pfn=%lx\n", dom, pfn);
> +                goto err_mapped;
> +            }
> +            continue;
> +        }
> +
>          if (pfn_err[i])
>          {
>              ERROR("unexpected PFN mapping failure pfn %lx map_mfn %lx 
> p2m_mfn %lx",
> diff -r a1d106d1aec8 xen/include/public/domctl.h
> --- a/xen/include/public/domctl.h     Wed Sep 19 03:31:31 2012 +0800
> +++ b/xen/include/public/domctl.h     Wed Sep 19 04:22:26 2012 +0800
> @@ -136,6 +136,7 @@
>  #define XEN_DOMCTL_PFINFO_LPINTAB (0x1U<<31)
>  #define XEN_DOMCTL_PFINFO_XTAB    (0xfU<<28) /* invalid page */
>  #define XEN_DOMCTL_PFINFO_XALLOC  (0xeU<<28) /* allocate-only page */
> +#define XEN_DOMCTL_PFINFO_BROKEN  (0xdU<<28) /* broken page */
>  #define XEN_DOMCTL_PFINFO_PAGEDTAB (0x8U<<28)
>  #define XEN_DOMCTL_PFINFO_LTAB_MASK (0xfU<<28)
>  
> @@ -834,6 +835,12 @@
>  typedef struct xen_domctl_vmce_monitor xen_domctl_vmce_monitor_t;
>  DEFINE_XEN_GUEST_HANDLE(xen_domctl_vmce_monitor_t);
>  
> +struct xen_domctl_set_broken_page_p2m {
> +    uint64_t pfn;
> +};

why not xen_pfn_t? or uint64_aligned_t?

Is domctl the right interface for this? Seems like more of an add to
physmap thing?

> +typedef struct xen_domctl_set_broken_page_p2m 
> xen_domctl_set_broken_page_p2m_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_domctl_set_broken_page_p2m_t);
> +
>  struct xen_domctl {
>      uint32_t cmd;
>  #define XEN_DOMCTL_createdomain                   1
> @@ -901,6 +908,7 @@
>  #define XEN_DOMCTL_set_virq_handler              66
>  #define XEN_DOMCTL_vmce_monitor_start            67
>  #define XEN_DOMCTL_vmce_monitor_end              68
> +#define XEN_DOMCTL_set_broken_page_p2m           69
>  #define XEN_DOMCTL_gdbsx_guestmemio            1000
>  #define XEN_DOMCTL_gdbsx_pausevcpu             1001
>  #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
> @@ -957,6 +965,7 @@
>          struct xen_domctl_set_virq_handler  set_virq_handler;
>          struct xen_domctl_vmce_monitor      vmce_monitor;
>          struct xen_domctl_gdbsx_memio       gdbsx_guest_memio;
> +        struct xen_domctl_set_broken_page_p2m set_broken_page_p2m;
>          struct xen_domctl_gdbsx_pauseunp_vcpu gdbsx_pauseunp_vcpu;
>          struct xen_domctl_gdbsx_domstatus   gdbsx_domstatus;
>          uint8_t                             pad[128];



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