Re: [Xen-devel] [RFC for-4.8 4/6] xen/arm: Add helper functions to map RWX memory regions

["Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxx>]

On Mon, May 23, 2016 at 04:36:03PM +0100, Julien Grall wrote:
> Hi Edgar,
> 
> On 20/05/16 16:51, Edgar E. Iglesias wrote:
> >From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxxx>
> >
> >Create a helper function to map regions as MEMORY with
> >cached attributes and read-write-execute permissions.
> 
> Providing setting the execute bit is useful, I would try to rationalize the
> helpers by expanding map_regions_rw_cache (and maybe rename it).

Thanks, I'll have change the code around to do that.

> 
> >Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxxxxx>
> >---
> >  xen/arch/arm/p2m.c        | 26 ++++++++++++++++++++++++++
> >  xen/include/asm-arm/p2m.h | 10 ++++++++++
> >  2 files changed, 36 insertions(+)
> >
> >diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> >index db21433..7e788f9 100644
> >--- a/xen/arch/arm/p2m.c
> >+++ b/xen/arch/arm/p2m.c
> >@@ -1219,6 +1219,32 @@ int p2m_populate_ram(struct domain *d,
> >                               d->arch.p2m.default_access);
> >  }
> >
> >+int map_regions_rwx_cache(struct domain *d,
> >+                         unsigned long start_gfn,
> >+                         unsigned long nr,
> >+                         unsigned long mfn)
> >+{
> >+    return apply_p2m_changes(d, INSERT,
> >+                             pfn_to_paddr(start_gfn),
> >+                             pfn_to_paddr(start_gfn + nr),
> >+                             pfn_to_paddr(mfn),
> >+                             MATTR_MEM, 0, p2m_ram_rw,
> 
> We should not use p2m_ram_rw for other mapping than DRAM. It could be used
> by Xen to differentiate MMIO vs RAM.


OK, I see. I'll fix that.

Cheers,
Edgar

> 
> >+                             p2m_access_rwx);
> >+}
> >+
> >+int unmap_regions_rwx_cache(struct domain *d,
> >+                           unsigned long start_gfn,
> >+                           unsigned long nr,
> >+                           unsigned long mfn)
> >+{
> >+    return apply_p2m_changes(d, REMOVE,
> >+                             pfn_to_paddr(start_gfn),
> >+                             pfn_to_paddr(start_gfn + nr),
> >+                             pfn_to_paddr(mfn),
> >+                             MATTR_MEM, 0, p2m_invalid,
> >+                             p2m_access_rwx);
> >+}
> >+
> >  int map_regions_rw_cache(struct domain *d,
> >                           unsigned long start_gfn,
> >                           unsigned long nr,
> >diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> >index d240d1e..294050e 100644
> >--- a/xen/include/asm-arm/p2m.h
> >+++ b/xen/include/asm-arm/p2m.h
> >@@ -144,6 +144,16 @@ int p2m_cache_flush(struct domain *d, xen_pfn_t 
> >start_mfn, xen_pfn_t end_mfn);
> >  /* Setup p2m RAM mapping for domain d from start-end. */
> >  int p2m_populate_ram(struct domain *d, paddr_t start, paddr_t end);
> >
> >+int map_regions_rwx_cache(struct domain *d,
> >+                          unsigned long start_gfn,
> >+                          unsigned long nr_mfns,
> >+                          unsigned long mfn);
> >+
> >+int unmap_regions_rwx_cache(struct domain *d,
> >+                            unsigned long start_gfn,
> >+                            unsigned long nr_mfns,
> >+                            unsigned long mfn);
> >+
> >  int map_regions_rw_cache(struct domain *d,
> >                           unsigned long start_gfn,
> >                           unsigned long nr_mfns,
> >
> 
> Regards,
> 
> -- 
> Julien Grall

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