[PATCH v2] arm/gicv3: Decode cacheability fields before comparing

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

From: Mykola Kvach <mykola_kvach@xxxxxxxx>

GITS_BASER_INNER_CACHEABILITY_MASK and
GICR_PROPBASER_INNER_CACHEABILITY_MASK are shifted masks. Comparing the
masked but unshifted values against GIC_BASER_CACHE_nC, which is an
unshifted enum value, leads to incorrect detection of non-cacheable
GITS_CBASER command queue, GITS_BASER tables, and GICR_PROPBASER
mappings.

Use MASK_EXTR() to decode these cacheability fields before comparing
against GIC_BASER_CACHE_nC, so the backing memory is flushed when
required.

Fixes: 8ed8d21373be ("ARM: GICv3 ITS: map ITS command buffer")
Fixes: 05238012b86d ("ARM: GICv3 ITS: allocate device and collection table")
Fixes: c9b939863c89 ("ARM: GICv3: allocate LPI pending and property table")
Signed-off-by: Mykyta Poturai <mykyta_poturai@xxxxxxxx>
Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
---
Changes in v2:
- use MASK_EXTR() instead of open-coding the BASER field shift
- fix the analogous PROPBASER cacheability comparison in
  gicv3_lpi_set_proptable()
- fix the CBASER command queue cacheability check as well
---
 xen/arch/arm/gic-v3-its.c | 6 ++++--
 xen/arch/arm/gic-v3-lpi.c | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index 9ba068c46f..e87465d2ff 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -424,7 +424,8 @@ static void *its_map_cbaser(struct host_its *its)
      * If the command queue memory is mapped as uncached, we need to flush
      * it on every access.
      */
-    if ( !(reg & GITS_BASER_INNER_CACHEABILITY_MASK) )
+    if ( MASK_EXTR(reg, GITS_BASER_INNER_CACHEABILITY_MASK) <=
+         GIC_BASER_CACHE_nC )
     {
         its->flags |= HOST_ITS_FLUSH_CMD_QUEUE;
         printk(XENLOG_WARNING "using non-cacheable ITS command queue\n");
@@ -496,7 +497,8 @@ retry:
         }
         attr = regc & BASER_ATTR_MASK;
     }
-    if ( (regc & GITS_BASER_INNER_CACHEABILITY_MASK) <= GIC_BASER_CACHE_nC )
+    if ( MASK_EXTR(regc, GITS_BASER_INNER_CACHEABILITY_MASK) <=
+         GIC_BASER_CACHE_nC )
         clean_and_invalidate_dcache_va_range(buffer, table_size);
 
     /* If the host accepted our page size, we are done. */
diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
index de5052e5cf..9ee338edc2 100644
--- a/xen/arch/arm/gic-v3-lpi.c
+++ b/xen/arch/arm/gic-v3-lpi.c
@@ -351,7 +351,8 @@ static int gicv3_lpi_set_proptable(void __iomem * 
rdist_base)
     }
 
     /* Remember that we have to flush the property table if non-cacheable. */
-    if ( (reg & GICR_PROPBASER_INNER_CACHEABILITY_MASK) <= GIC_BASER_CACHE_nC )
+    if ( MASK_EXTR(reg, GICR_PROPBASER_INNER_CACHEABILITY_MASK) <=
+         GIC_BASER_CACHE_nC )
     {
         lpi_data.flags |= LPI_PROPTABLE_NEEDS_FLUSHING;
         /* Update the redistributors knowledge about the attributes. */
-- 
2.43.0