Re: [Xen-devel] [PATCH v4 09/16] xen/arm: p2m type definitions and changes

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Tamas,

On 05/09/14 01:58, Tamas K Lengyel wrote:
> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> index 06c93a0..b2009ee 100644
> --- a/xen/include/asm-arm/p2m.h
> +++ b/xen/include/asm-arm/p2m.h
> @@ -2,9 +2,54 @@
[..]

> +#include <public/memory.h>
> +#include <public/mem_event.h>
Why do you need this 2 includes?

>   struct domain;
>
> +/* List of possible type for each page in the p2m entry.
> + * The number of available bit per page in the pte for this purpose is 4 bits.
> + * So it's possible to only have 16 fields. If we run out of value in the
> + * future, it's possible to use higher value for pseudo-type and don't store
> + * them in the p2m entry.
> + */
> +typedef enum {
> +    p2m_invalid = 0,    /* Nothing mapped here */
> +    p2m_ram_rw,         /* Normal read/write guest RAM */
> +    p2m_ram_ro,         /* Read-only; writes are silently dropped */
> +    p2m_mmio_direct,    /* Read/write mapping of genuine MMIO area */
> +    p2m_map_foreign,    /* Ram pages from foreign domain */
> +    p2m_grant_map_rw,   /* Read/write grant mapping */
> +    p2m_grant_map_ro,   /* Read-only grant mapping */
> +    /* The types below are only used to decide the page attribute in the P2M */
> +    p2m_iommu_map_rw,   /* Read/write iommu mapping */
> +    p2m_iommu_map_ro,   /* Read-only iommu mapping */
> +    p2m_max_real_type,  /* Types after this won't be store in the p2m */
> +} p2m_type_t;
> +
Any reason to move the enum earlier? If not, I would prefer to keep at 
the same place. It will be easier with git-blame to find when a new type 
has been added.
> +/*
> + * Additional access types, which are used to further restrict
> + * the permissions given by the p2m_type_t memory type. Violations
> + * caused by p2m_access_t restrictions are sent to the mem_event
> + * interface.
> + *
> + * The access permissions are soft state: when any ambigious change of page
ambiguous

[..]

> +    /* Default P2M access type for each page in the the domain: new pages,
> +     * swapped in pages, cleared pages, and pages that are ambiquously
Did you intend to mean ambiguously rather than ambiquously?

[..]

> +/* get host p2m table */
> +#define p2m_get_hostp2m(d) (&((d)->arch.p2m))
> +
> +/* mem_event and mem_access are supported on all ARM */
I don't find "all ARM" clear. I would replace by "any ARM guest"

Regards,

--
Julien Grall

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