[PATCH] xen/pci: replace call to is_memory_hole to pci_check_bar

[Rahul Singh <rahul.singh@xxxxxxx>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

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@xxxxxxx>
---
 xen/arch/arm/include/asm/pci.h     | 12 ++++++++++
 xen/arch/arm/pci/pci-host-common.c | 35 ++++++++++++++++++++++++++++++
 xen/arch/x86/include/asm/pci.h     | 10 +++++++++
 xen/drivers/passthrough/pci.c      |  8 +++----
 4 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/include/asm/pci.h b/xen/arch/arm/include/asm/pci.h
index 7c7449d64f..5c4ab2c4dc 100644
--- a/xen/arch/arm/include/asm/pci.h
+++ b/xen/arch/arm/include/asm/pci.h
@@ -91,6 +91,16 @@ struct pci_ecam_ops {
     int (*init)(struct pci_config_window *);
 };
 
+/*
+ * struct to hold pci device bar.
+ */
+struct pdev_bar
+{
+    mfn_t start;
+    mfn_t end;
+    bool is_valid;
+};
+
 /* Default ECAM ops */
 extern const struct pci_ecam_ops pci_generic_ecam_ops;
 
@@ -125,6 +135,8 @@ 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 { };
diff --git a/xen/arch/arm/pci/pci-host-common.c 
b/xen/arch/arm/pci/pci-host-common.c
index fd8c0f837a..8ea1aaeece 100644
--- a/xen/arch/arm/pci/pci-host-common.c
+++ b/xen/arch/arm/pci/pci-host-common.c
@@ -363,6 +363,41 @@ int __init pci_host_bridge_mappings(struct domain *d)
     return 0;
 }
 
+static int is_bar_valid(const struct dt_device_node *dev,
+                        u64 addr, u64 len, void *data)
+{
+    struct pdev_bar *bar_data = data;
+    unsigned long s = mfn_x(bar_data->start);
+    unsigned long e = mfn_x(bar_data->end);
+
+    if ( (s < e) && (s >= PFN_DOWN(addr)) && (e<= PFN_DOWN(addr + len - 1)) )
+        bar_data->is_valid =  true;
+
+    return 0;
+}
+
+bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end)
+{
+    int ret;
+    struct dt_device_node *dt_node;
+    struct device *dev = (struct device *)pci_to_dev(pdev);
+    struct pdev_bar bar_data =  {
+        .start = start,
+        .end = end,
+        .is_valid = false
+    };
+
+    dt_node = pci_find_host_bridge_node(dev);
+
+    ret = dt_for_each_range(dt_node, &is_bar_valid, &bar_data);
+    if ( ret < 0 )
+        return ret;
+
+    if ( !bar_data.is_valid )
+        return false;
+
+    return true;
+}
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/include/asm/pci.h b/xen/arch/x86/include/asm/pci.h
index c8e1a9ecdb..f4a58c8acf 100644
--- a/xen/arch/x86/include/asm/pci.h
+++ b/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__ */
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 29356d59a7..52453a05fe 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/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));
-- 
2.25.1