xen/pci: replace call to is_memory_hole to pci_check_bar

is_memory_hole was implemented for x86 and not for ARM when introduced.
Replace is_memory_hole call to pci_check_bar as function should check
if device BAR is in defined memory range. Also, add an implementation
for ARM which is required for PCI passthrough.

On x86, pci_check_bar will call is_memory_hole which will check if BAR
is not overlapping with any memory region defined in the memory map.

On ARM, pci_check_bar will go through the host bridge ranges and check
if the BAR is in the range of defined ranges.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/include/asm/pci.h

@@ -126,6 +126,8 @@ int pci_host_iterate_bridges_and_count(struct domain *d,
 
 int pci_host_bridge_mappings(struct domain *d);
 
+bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end);
+
 #else   /*!CONFIG_HAS_PCI*/
 
 struct arch_pci_dev { };

xen/arch/arm/pci/pci-host-common.c

@@ -24,6 +24,16 @@
 
 #include <asm/setup.h>
 
+/*
+ * struct to hold pci device bar.
+ */
+struct pdev_bar_check
+{
+    paddr_t start;
+    paddr_t end;
+    bool is_valid;
+};
+
 /*
  * List for all the pci host bridges.
  */
@@ -363,6 +373,50 @@ int __init pci_host_bridge_mappings(struct domain *d)
     return 0;
 }
 
+/*
+ * TODO: BAR addresses and Root Complex window addresses are not guaranteed
+ * to be page aligned. We should check for alignment but this is not the
+ * right place for alignment check.
+ */
+static int is_bar_valid(const struct dt_device_node *dev,
+                        paddr_t addr, paddr_t len, void *data)
+{
+    struct pdev_bar_check *bar_data = data;
+    paddr_t s = bar_data->start;
+    paddr_t e = bar_data->end;
+
+    if ( (s >= addr) && (e <= (addr + len - 1)) )
+        bar_data->is_valid =  true;
+
+    return 0;
+}
+
+/* TODO: Revisit this function when ACPI PCI passthrough support is added. */
+bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end)
+{
+    int ret;
+    const struct dt_device_node *dt_node;
+    paddr_t s = mfn_to_maddr(start);
+    paddr_t e = mfn_to_maddr(end);
+    struct pdev_bar_check bar_data =  {
+        .start = s,
+        .end = e,
+        .is_valid = false
+    };
+
+    if ( s >= e )
+        return false;
+
+    dt_node = pci_find_host_bridge_node(pdev);
+    if ( !dt_node )
+        return false;
+
+    ret = dt_for_each_range(dt_node, &is_bar_valid, &bar_data);
+    if ( ret < 0 )
+        return false;
+
+    return bar_data.is_valid;
+}
 /*
  * Local variables:
  * mode: C

xen/arch/x86/include/asm/pci.h

@@ -57,4 +57,14 @@ static always_inline bool is_pci_passthrough_enabled(void)
 
 void arch_pci_init_pdev(struct pci_dev *pdev);
 
+static inline bool pci_check_bar(const struct pci_dev *pdev,
+                                 mfn_t start, mfn_t end)
+{
+    /*
+     * Check if BAR is not overlapping with any memory region defined
+     * in the memory map.
+     */
+    return is_memory_hole(start, end);
+}
+
 #endif /* __X86_PCI_H__ */

xen/drivers/passthrough/pci.c

@@ -304,8 +304,8 @@ static void check_pdev(const struct pci_dev *pdev)
         if ( rc < 0 )
             /* Unable to size, better leave memory decoding disabled. */
             return;
-        if ( size && !is_memory_hole(maddr_to_mfn(addr),
-                                     maddr_to_mfn(addr + size - 1)) )
+        if ( size && !pci_check_bar(pdev, maddr_to_mfn(addr),
+                                    maddr_to_mfn(addr + size - 1)) )
         {
             /*
              * Return without enabling memory decoding if BAR position is not
@@ -331,8 +331,8 @@ static void check_pdev(const struct pci_dev *pdev)
 
         if ( rc < 0 )
             return;
-        if ( size && !is_memory_hole(maddr_to_mfn(addr),
-                                     maddr_to_mfn(addr + size - 1)) )
+        if ( size && !pci_check_bar(pdev, maddr_to_mfn(addr),
+                                    maddr_to_mfn(addr + size - 1)) )
         {
             printk(warn, &pdev->sbdf, "ROM ", PFN_DOWN(addr),
                    PFN_DOWN(addr + size - 1));