[PATCH 10/11] xen/arm: Do not map PCI ECAM space to Domain-0's p2m

[Oleksandr Andrushchenko <andr2000@xxxxxxxxx>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

Host bridge controller's ECAM space is mapped into Domain-0's p2m,
thus it is not possible to trap the same for vPCI via MMIO handlers.
For this to work we need to not map those while constructing the domain.

Note, that during Domain-0 creation there is no pci_dev yet allocated for
host bridges, thus we cannot match PCI host and its associated
bridge by SBDF. Use dt_device_node field for checks instead.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
---
 xen/arch/arm/domain_build.c        |  3 +++
 xen/arch/arm/pci/ecam.c            | 17 +++++++++++++++++
 xen/arch/arm/pci/pci-host-common.c | 22 ++++++++++++++++++++++
 xen/include/asm-arm/pci.h          | 12 ++++++++++++
 4 files changed, 54 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index da427f399711..76f5b513280c 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1257,6 +1257,9 @@ static int __init map_range_to_domain(const struct 
dt_device_node *dev,
         }
     }
 
+    if ( need_mapping && (device_get_class(dev) == DEVICE_PCI) )
+        need_mapping = pci_host_bridge_need_p2m_mapping(d, dev, addr, len);
+
     if ( need_mapping )
     {
         res = map_regions_p2mt(d,
diff --git a/xen/arch/arm/pci/ecam.c b/xen/arch/arm/pci/ecam.c
index 92ecb2e0762b..d32efb7fcbd0 100644
--- a/xen/arch/arm/pci/ecam.c
+++ b/xen/arch/arm/pci/ecam.c
@@ -52,6 +52,22 @@ static int pci_ecam_register_mmio_handler(struct domain *d,
     return 0;
 }
 
+static int pci_ecam_need_p2m_mapping(struct domain *d,
+                                     struct pci_host_bridge *bridge,
+                                     uint64_t addr, uint64_t len)
+{
+    struct pci_config_window *cfg = bridge->sysdata;
+
+    if ( !is_hardware_domain(d) )
+        return true;
+
+    /*
+     * We do not want ECAM address space to be mapped in domain's p2m,
+     * so we can trap access to it.
+     */
+    return cfg->phys_addr != addr;
+}
+
 /* ECAM ops */
 const struct pci_ecam_ops pci_generic_ecam_ops = {
     .bus_shift  = 20,
@@ -60,6 +76,7 @@ const struct pci_ecam_ops pci_generic_ecam_ops = {
         .read                   = pci_generic_config_read,
         .write                  = pci_generic_config_write,
         .register_mmio_handler  = pci_ecam_register_mmio_handler,
+        .need_p2m_mapping       = pci_ecam_need_p2m_mapping,
     }
 };
 
diff --git a/xen/arch/arm/pci/pci-host-common.c 
b/xen/arch/arm/pci/pci-host-common.c
index a89112bfbb7c..c04be636452d 100644
--- a/xen/arch/arm/pci/pci-host-common.c
+++ b/xen/arch/arm/pci/pci-host-common.c
@@ -334,6 +334,28 @@ int pci_host_iterate_bridges(struct domain *d,
     }
     return 0;
 }
+
+bool pci_host_bridge_need_p2m_mapping(struct domain *d,
+                                      const struct dt_device_node *node,
+                                      uint64_t addr, uint64_t len)
+{
+    struct pci_host_bridge *bridge;
+
+    list_for_each_entry( bridge, &pci_host_bridges, node )
+    {
+        if ( bridge->dt_node != node )
+            continue;
+
+        if ( !bridge->ops->need_p2m_mapping )
+            return true;
+
+        return bridge->ops->need_p2m_mapping(d, bridge, addr, len);
+    }
+    printk(XENLOG_ERR "Unable to find PCI bridge for %s segment %d, addr 
%lx\n",
+           node->full_name, bridge->segment, addr);
+    return true;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/pci.h b/xen/include/asm-arm/pci.h
index 2c7c7649e00f..9c28a4bdc4b7 100644
--- a/xen/include/asm-arm/pci.h
+++ b/xen/include/asm-arm/pci.h
@@ -82,6 +82,8 @@ struct pci_ops {
     int (*register_mmio_handler)(struct domain *d,
                                  struct pci_host_bridge *bridge,
                                  const struct mmio_handler_ops *ops);
+    int (*need_p2m_mapping)(struct domain *d, struct pci_host_bridge *bridge,
+                            uint64_t addr, uint64_t len);
 };
 
 /*
@@ -115,9 +117,19 @@ struct dt_device_node *pci_find_host_bridge_node(struct 
device *dev);
 int pci_host_iterate_bridges(struct domain *d,
                              int (*clb)(struct domain *d,
                                         struct pci_host_bridge *bridge));
+bool pci_host_bridge_need_p2m_mapping(struct domain *d,
+                                      const struct dt_device_node *node,
+                                      uint64_t addr, uint64_t len);
 #else   /*!CONFIG_HAS_PCI*/
 
 struct arch_pci_dev { };
 
+static inline bool
+pci_host_bridge_need_p2m_mapping(struct domain *d,
+                                 const struct dt_device_node *node,
+                                 uint64_t addr, uint64_t len)
+{
+    return true;
+}
 #endif  /*!CONFIG_HAS_PCI*/
 #endif /* __ARM_PCI_H__ */
-- 
2.25.1