[PATCH v4 08/11] libxl: Only map legacy PCI IRQs if they are supported

[Oleksandr Andrushchenko <andr2000@xxxxxxxxx>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

Arm's PCI passthrough implementation doesn't support legacy interrupts,
but MSI/MSI-X. This can be the case for other platforms too.
For that reason introduce a new CONFIG_PCI_SUPP_LEGACY_IRQ and add
it to the CFLAGS and compile the relevant code in the toolstack only if
applicable.

Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
Since v1:
 - Minimized #idefery by introducing pci_supp_legacy_irq function
   for relevant checks
---
 tools/libs/light/Makefile    |  4 ++++
 tools/libs/light/libxl_pci.c | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
index 7d8c51d49242..bd3f6be2a183 100644
--- a/tools/libs/light/Makefile
+++ b/tools/libs/light/Makefile
@@ -46,6 +46,10 @@ CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
        -Wno-declaration-after-statement -Wformat-nonliteral
 CFLAGS += -I.
 
+ifeq ($(CONFIG_X86),y)
+CFLAGS += -DCONFIG_PCI_SUPP_LEGACY_IRQ
+endif
+
 SRCS-$(CONFIG_X86) += libxl_cpuid.c
 SRCS-$(CONFIG_X86) += libxl_x86.c
 SRCS-$(CONFIG_X86) += libxl_psr.c
diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
index 59f3686fc85e..4c2d7aeefbb2 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -1364,6 +1364,15 @@ static void pci_add_timeout(libxl__egc *egc, 
libxl__ev_time *ev,
     pci_add_dm_done(egc, pas, rc);
 }
 
+static bool pci_supp_legacy_irq(void)
+{
+#ifdef CONFIG_PCI_SUPP_LEGACY_IRQ
+    return true;
+#else
+    return false;
+#endif
+}
+
 static void pci_add_dm_done(libxl__egc *egc,
                             pci_add_state *pas,
                             int rc)
@@ -1434,6 +1443,8 @@ static void pci_add_dm_done(libxl__egc *egc,
         }
     }
     fclose(f);
+    if (!pci_supp_legacy_irq())
+        goto out_no_irq;
     sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
                                 pci->bus, pci->dev, pci->func);
     f = fopen(sysfs_path, "r");
@@ -1983,6 +1994,8 @@ static void do_pci_remove(libxl__egc *egc, 
pci_remove_state *prs)
         }
         fclose(f);
 skip1:
+        if (!pci_supp_legacy_irq())
+            goto skip_irq;
         sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
                                pci->bus, pci->dev, pci->func);
         f = fopen(sysfs_path, "r");
-- 
2.25.1