[PATCH 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.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
---
 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..cd4fea46c3f7 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -1434,6 +1434,7 @@ static void pci_add_dm_done(libxl__egc *egc,
         }
     }
     fclose(f);
+#ifndef CONFIG_PCI_SUPP_LEGACY_IRQ
     sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
                                 pci->bus, pci->dev, pci->func);
     f = fopen(sysfs_path, "r");
@@ -1460,6 +1461,7 @@ static void pci_add_dm_done(libxl__egc *egc,
         }
     }
     fclose(f);
+#endif
 
     /* Don't restrict writes to the PCI config space from this VM */
     if (pci->permissive) {
@@ -1471,7 +1473,9 @@ static void pci_add_dm_done(libxl__egc *egc,
         }
     }
 
+#ifndef CONFIG_PCI_SUPP_LEGACY_IRQ
 out_no_irq:
+#endif
     if (!isstubdom) {
         if (pci->rdm_policy == LIBXL_RDM_RESERVE_POLICY_STRICT) {
             flag &= ~XEN_DOMCTL_DEV_RDM_RELAXED;
@@ -1951,7 +1955,9 @@ static void do_pci_remove(libxl__egc *egc, 
pci_remove_state *prs)
                                      pci->bus, pci->dev, pci->func);
         FILE *f = fopen(sysfs_path, "r");
         unsigned int start = 0, end = 0, flags = 0, size = 0;
+#ifndef CONFIG_PCI_SUPP_LEGACY_IRQ
         int irq = 0;
+#endif
         int i;
 
         if (f == NULL) {
@@ -1983,6 +1989,7 @@ static void do_pci_remove(libxl__egc *egc, 
pci_remove_state *prs)
         }
         fclose(f);
 skip1:
+#ifndef CONFIG_PCI_SUPP_LEGACY_IRQ
         sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
                                pci->bus, pci->dev, pci->func);
         f = fopen(sysfs_path, "r");
@@ -2001,8 +2008,14 @@ skip1:
             }
         }
         fclose(f);
+#else
+        /* Silence error: label at end of compound statement */
+        ;
+#endif
     }
+#ifndef CONFIG_PCI_SUPP_LEGACY_IRQ
 skip_irq:
+#endif
     rc = 0;
 out_fail:
     pci_remove_detached(egc, prs, rc); /* must be last */
-- 
2.25.1