[Xen-devel] [PATCH v8 20/21] xen/arm: Add a hypercall for device mmio mapping

[Shannon Zhao <zhaoshenglong@xxxxxxxxxx>]

From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>

It needs to map platform or amba device mmio to Dom0 on ARM. But when
booting with ACPI, it can't get the mmio region in Xen due to lack of
AML interpreter to parse DSDT table. Therefore, let Dom0 call a
hypercall to map mmio region when it adds the devices.

Here we add a new map space like the XEN_DOMCTL_memory_mapping to map
mmio region for Dom0. Also add a helper to combine the
xsm_add_to_physmap and XENMAPSPACE_dev_mmio space check together.

Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
v8: add a helper to combine xsm_add_to_physmap and XENMAPSPACE_dev_mmio
space check together
---
 xen/arch/arm/mm.c           |  3 +++
 xen/arch/arm/p2m.c          | 22 ++++++++++++++++++++++
 xen/common/memory.c         | 17 +++++++++++++++--
 xen/include/asm-arm/p2m.h   |  5 +++++
 xen/include/public/memory.h |  1 +
 5 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 81f9e2e..0aae6c5 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1138,6 +1138,9 @@ int xenmem_add_to_physmap_one(
         rcu_unlock_domain(od);
         break;
     }
+    case XENMAPSPACE_dev_mmio:
+        rc = map_dev_mmio_region(d, gpfn, 1, idx);
+        return rc;
 
     default:
         return -ENOSYS;
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 7e5f5d1..0011708 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -7,6 +7,7 @@
 #include <xen/bitops.h>
 #include <xen/vm_event.h>
 #include <xen/mem_access.h>
+#include <xen/iocap.h>
 #include <public/vm_event.h>
 #include <asm/flushtlb.h>
 #include <asm/gic.h>
@@ -1270,6 +1271,27 @@ int unmap_mmio_regions(struct domain *d,
                              d->arch.p2m.default_access);
 }
 
+int map_dev_mmio_region(struct domain *d,
+                        unsigned long start_gfn,
+                        unsigned long nr,
+                        unsigned long mfn)
+{
+    int res;
+
+    if ( !(nr && iomem_access_permitted(d, start_gfn, start_gfn + nr - 1)) )
+        return 0;
+
+    res = map_mmio_regions(d, start_gfn, nr, mfn);
+    if ( res < 0 )
+    {
+        printk(XENLOG_ERR "Unable to map [%#lx - %#lx] in Dom%d\n",
+               start_gfn, start_gfn + nr - 1, d->domain_id);
+        return res;
+    }
+
+    return 0;
+}
+
 int guest_physmap_add_entry(struct domain *d,
                             unsigned long gpfn,
                             unsigned long mfn,
diff --git a/xen/common/memory.c b/xen/common/memory.c
index c7fca96..644f81a 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -834,6 +834,19 @@ static int get_reserved_device_memory(xen_pfn_t start, 
xen_ulong_t nr,
 }
 #endif
 
+static long xatp_permission_check(struct domain *d, unsigned int space)
+{
+    /*
+     * XENMAPSPACE_dev_mmio mapping is only supported for hardware Domain
+     * to map this kind of space to itself.
+     */
+    if ( (space == XENMAPSPACE_dev_mmio) &&
+         (!is_hardware_domain(current->domain) || (d != current->domain)) )
+        return -EACCES;
+
+    return xsm_add_to_physmap(XSM_TARGET, current->domain, d);
+}
+
 long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     struct domain *d;
@@ -980,7 +993,7 @@ long do_memory_op(unsigned long cmd, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         if ( d == NULL )
             return -ESRCH;
 
-        rc = xsm_add_to_physmap(XSM_TARGET, current->domain, d);
+        rc = xatp_permission_check(d, xatp.space);
         if ( rc )
         {
             rcu_unlock_domain(d);
@@ -1024,7 +1037,7 @@ long do_memory_op(unsigned long cmd, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         if ( d == NULL )
             return -ESRCH;
 
-        rc = xsm_add_to_physmap(XSM_TARGET, current->domain, d);
+        rc = xatp_permission_check(d, xatpb.space);
         if ( rc )
         {
             rcu_unlock_domain(d);
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 55626b4..d240d1e 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -154,6 +154,11 @@ int unmap_regions_rw_cache(struct domain *d,
                            unsigned long nr_mfns,
                            unsigned long mfn);
 
+int map_dev_mmio_region(struct domain *d,
+                        unsigned long start_gfn,
+                        unsigned long nr,
+                        unsigned long mfn);
+
 int guest_physmap_add_entry(struct domain *d,
                             unsigned long gfn,
                             unsigned long mfn,
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index f69e92f..fe52ee1 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -220,6 +220,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_machphys_mapping_t);
 #define XENMAPSPACE_gmfn_range   3 /* GMFN range, XENMEM_add_to_physmap only. 
*/
 #define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another dom,
                                     * XENMEM_add_to_physmap_batch only. */
+#define XENMAPSPACE_dev_mmio     5 /* device mmio region */
 /* ` } */
 
 /*
-- 
2.0.4



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