[xen master] tools/libxl: Skip invalid IRQs

[patchbot@xxxxxxx]

commit ec9fda045b517128e2173fa7b87bf6aee9dcc33a
Author:     Jason Andryuk <jason.andryuk@xxxxxxx>
AuthorDate: Fri Apr 18 17:05:49 2025 -0400
Commit:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
CommitDate: Fri Apr 25 11:44:48 2025 +0200

    tools/libxl: Skip invalid IRQs
    
    A PCI device's irq field is an 8-bit number.  A value of 0xff indicates
    that the device IRQ is not connected.  Additionally, the Linux ACPI code
    can convert these 0xff values to IRQ_NOTCONNECTED(0x80000000) because
    "0x80000000 is guaranteed to be outside the available range of
    interrupts and easy to distinguish from other possible incorrect
    values."  When the hypercall to assign that IRQ fails, device
    passthrough as a whole fails.
    
    Add checking for a valid IRQ and skip the IRQ handling for PCI devices
    outside that range.  This allows for passthrough of devices without
    legacy IRQs.
    
    Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
    Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/libs/light/libxl_pci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
index 1647fd6f47..6ddcdef6ad 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -26,6 +26,9 @@
 #define PCI_BDF_XSPATH         "%04x-%02x-%02x-%01x"
 #define PCI_PT_QDEV_ID         "pci-pt-%02x_%02x.%01x"
 
+/* PCI Interrupt Line is an 8-bit value, 0xff means disconnected. */
+#define PCI_IRQ_LINE_LIMIT     0xff
+
 static unsigned int pci_encode_bdf(libxl_device_pci *pci)
 {
     unsigned int value;
@@ -1495,7 +1498,7 @@ static void pci_add_dm_done(libxl__egc *egc,
             LOGED(ERROR, domainid, "Couldn't open %s", sysfs_path);
             goto out_no_irq;
         }
-        if ((fscanf(f, "%u", &irq) == 1) && irq) {
+        if (fscanf(f, "%u", &irq) == 1 && irq > 0 && irq < PCI_IRQ_LINE_LIMIT) 
{
             r = xc_physdev_map_pirq(ctx->xch, domid, irq, &irq);
             if (r < 0) {
                 LOGED(ERROR, domainid, "xc_physdev_map_pirq irq=%d (error=%d)",
@@ -2257,7 +2260,7 @@ skip_bar:
             goto skip_legacy_irq;
         }
 
-        if ((fscanf(f, "%u", &irq) == 1) && irq) {
+        if (fscanf(f, "%u", &irq) == 1 && irq > 0 && irq < PCI_IRQ_LINE_LIMIT) 
{
             rc = xc_physdev_unmap_pirq(ctx->xch, domid, irq);
             if (rc < 0) {
                 /*
--
generated by git-patchbot for /home/xen/git/xen.git#master