Re: [Xen-devel] [PATCH] x86/mem_access: fixed vm_event emulation check with altp2m enabled

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.03.17 at 10:28, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
> --- a/xen/arch/x86/mm/mem_access.c
> +++ b/xen/arch/x86/mm/mem_access.c
> @@ -32,14 +32,68 @@
>  
>  #include "mm-locks.h"
>  
> +/*
> + * Get access type for a gfn.
> + * If gfn == INVALID_GFN, gets the default access type.
> + */
> +static int _p2m_get_mem_access(struct p2m_domain *p2m, gfn_t gfn,
> +                               xenmem_access_t *access)
> +{
> +    p2m_type_t t;
> +    p2m_access_t a;
> +    mfn_t mfn;
> +
> +    static const xenmem_access_t memaccess[] = {
> +#define ACCESS(ac) [p2m_access_##ac] = XENMEM_access_##ac
> +            ACCESS(n),
> +            ACCESS(r),
> +            ACCESS(w),
> +            ACCESS(rw),
> +            ACCESS(x),
> +            ACCESS(rx),
> +            ACCESS(wx),
> +            ACCESS(rwx),
> +            ACCESS(rx2rw),
> +            ACCESS(n2rwx),
> +#undef ACCESS
> +    };
> +
> +    /* If request to get default access. */
> +    if ( gfn_eq(gfn, INVALID_GFN) )
> +    {
> +        *access = memaccess[p2m->default_access];
> +        return 0;
> +    }
> +
> +    gfn_lock(p2m, gfn, 0);
> +    mfn = p2m->get_entry(p2m, gfn_x(gfn), &t, &a, 0, NULL, NULL);
> +    gfn_unlock(p2m, gfn, 0);
> +
> +    if ( mfn_eq(mfn, INVALID_MFN) )
> +        return -ESRCH;
> +
> +    if ( (unsigned) a >= ARRAY_SIZE(memaccess) )

Granted you're just moving this code here, but while doing so you
could have removed the stray blank and added the missing "int"
from/to the cast expression. Unless there's a need for a v2 this
could of course be adjusted upon commit.

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan


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