Re: [Xen-devel] [v8][PATCH 14/17] xen/x86/p2m: introduce set_identity_p2m_entry

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Mon, Dec 01, 2014 at 05:24:32PM +0800, Tiejun Chen wrote:
> We will create RMRR mapping as follows:
> 
> If gfn space unoccupied, we just set that. If
> space already occupy by 1:1 RMRR mapping do thing. Others

What is 'do thing'?

It looks as if we do nothing. Is that what you meant?

> should be failed.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> ---
>  xen/arch/x86/mm/p2m.c     | 28 ++++++++++++++++++++++++++++
>  xen/include/asm-x86/p2m.h |  4 ++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index 607ecd0..c415521 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -913,6 +913,34 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long 
> gfn, mfn_t mfn)
>      return set_typed_p2m_entry(d, gfn, mfn, p2m_mmio_direct);
>  }
>  
> +int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
> +                           p2m_access_t p2ma)
> +{
> +    p2m_type_t p2mt;
> +    p2m_access_t a;
> +    mfn_t mfn;
> +    struct p2m_domain *p2m = p2m_get_hostp2m(d);
> +    int ret = -EBUSY;
> +
> +    gfn_lock(p2m, gfn, 0);
> +
> +    mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL);
> +
> +    if ( !mfn_valid(mfn) )
> +        ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, 
> p2m_mmio_direct,
> +                            p2ma);
> +    else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2ma )
> +        ret = 0;
> +    else
> +        printk(XENLOG_G_WARNING
> +               "Cannot identity map d%d:%lx, already mapped to %lx.\n",
> +               d->domain_id, gfn, mfn_x(mfn));
> +
> +    gfn_unlock(p2m, gfn, 0);
> +
> +    return ret;
> +}
> +
>  /* Returns: 0 for success, -errno for failure */
>  int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
>  {
> diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
> index 99f7fb7..26cf0cc 100644
> --- a/xen/include/asm-x86/p2m.h
> +++ b/xen/include/asm-x86/p2m.h
> @@ -509,6 +509,10 @@ int p2m_is_logdirty_range(struct p2m_domain *, unsigned 
> long start,
>  int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
>  int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
>  
> +/* Set identity addresses in the p2m table (for pass-through) */
> +int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
> +                           p2m_access_t p2ma);
> +
>  /* Add foreign mapping to the guest's p2m table. */
>  int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
>                      unsigned long gpfn, domid_t foreign_domid);
> -- 
> 1.9.1
> 

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