[Xen-devel] [PATCH v2 03/15] xen/arm: p2m: Differentiate cacheable vs non-cacheable MMIO

[Julien Grall <julien.grall@xxxxxxx>]

Currently, the p2m type p2m_mmio_direct is used to map in stage-2
cacheable MMIO (via map_regions_rw_cache) and non-cacheable one (via
map_mmio_regions). The p2m code is relying on the caller to give the
correct memory attribute.

In a follow-up patch, the p2m code will rely on the p2m type to find the
correct memory attribute. In preparation of this, introduce
p2m_mmio_direct_nc and p2m_mimo_direct_c to differentiate the
cacheability of the MMIO.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/arch/arm/p2m.c        | 7 ++++---
 xen/include/asm-arm/p2m.h | 3 ++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 851b110..cffb12e 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -272,7 +272,8 @@ static void p2m_set_permission(lpae_t *e, p2m_type_t t, 
p2m_access_t a)
     case p2m_iommu_map_rw:
     case p2m_map_foreign:
     case p2m_grant_map_rw:
-    case p2m_mmio_direct:
+    case p2m_mmio_direct_nc:
+    case p2m_mmio_direct_c:
         e->p2m.xn = 1;
         e->p2m.write = 1;
         break;
@@ -1194,7 +1195,7 @@ int map_regions_rw_cache(struct domain *d,
                          mfn_t mfn)
 {
     return p2m_insert_mapping(d, gfn, nr, mfn,
-                              MATTR_MEM, p2m_mmio_direct);
+                              MATTR_MEM, p2m_mmio_direct_c);
 }
 
 int unmap_regions_rw_cache(struct domain *d,
@@ -1211,7 +1212,7 @@ int map_mmio_regions(struct domain *d,
                      mfn_t mfn)
 {
     return p2m_insert_mapping(d, start_gfn, nr, mfn,
-                              MATTR_DEV, p2m_mmio_direct);
+                              MATTR_DEV, p2m_mmio_direct_nc);
 }
 
 int unmap_mmio_regions(struct domain *d,
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 78d37ab..20a220ea 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -87,7 +87,8 @@ 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_mmio_direct_nc, /* Read/write mapping of genuine MMIO area 
non-cacheable */
+    p2m_mmio_direct_c,  /* Read/write mapping of genuine MMIO area cacheable */
     p2m_map_foreign,    /* Ram pages from foreign domain */
     p2m_grant_map_rw,   /* Read/write grant mapping */
     p2m_grant_map_ro,   /* Read-only grant mapping */
-- 
1.9.1


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