diff --git a/tools/include/xencall.h b/tools/include/xencall.h
index fc95ed0fe58e..962cb45e1f1b 100644
--- a/tools/include/xencall.h
+++ b/tools/include/xencall.h
@@ -113,6 +113,8 @@ int xencall5(xencall_handle *xcall, unsigned int op,
              uint64_t arg1, uint64_t arg2, uint64_t arg3,
              uint64_t arg4, uint64_t arg5);
 
+int xen_oscall_gsi_from_irq(xencall_handle *xcall, int irq);
+
 /* Variant(s) of the above, as needed, returning "long" instead of "int". */
 long xencall2L(xencall_handle *xcall, unsigned int op,
                uint64_t arg1, uint64_t arg2);
diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 2ef8b4e05422..2b9d55d2c6d7 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -1641,6 +1641,8 @@ int xc_physdev_unmap_pirq(xc_interface *xch,
                           uint32_t domid,
                           int pirq);
 
+int xc_physdev_gsi_from_irq(xc_interface *xch, int irq);
+
 /*
  *  LOGGING AND ERROR REPORTING
  */
diff --git a/tools/libs/call/core.c b/tools/libs/call/core.c
index 02c4f8e1aefa..6f79f3babd19 100644
--- a/tools/libs/call/core.c
+++ b/tools/libs/call/core.c
@@ -173,6 +173,11 @@ int xencall5(xencall_handle *xcall, unsigned int op,
     return osdep_hypercall(xcall, &call);
 }
 
+int xen_oscall_gsi_from_irq(xencall_handle *xcall, int irq)
+{
+    return osdep_oscall(xcall, irq);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/call/libxencall.map b/tools/libs/call/libxencall.map
index d18a3174e9dc..6cde8eda05e2 100644
--- a/tools/libs/call/libxencall.map
+++ b/tools/libs/call/libxencall.map
@@ -10,6 +10,8 @@ VERS_1.0 {
 		xencall4;
 		xencall5;
 
+		xen_oscall_gsi_from_irq;
+
 		xencall_alloc_buffer;
 		xencall_free_buffer;
 		xencall_alloc_buffer_pages;
diff --git a/tools/libs/call/linux.c b/tools/libs/call/linux.c
index 6d588e6bea8f..32b60c8b403e 100644
--- a/tools/libs/call/linux.c
+++ b/tools/libs/call/linux.c
@@ -85,6 +85,21 @@ long osdep_hypercall(xencall_handle *xcall, privcmd_hypercall_t *hypercall)
     return ioctl(xcall->fd, IOCTL_PRIVCMD_HYPERCALL, hypercall);
 }
 
+long osdep_oscall(xencall_handle *xcall, int irq)
+{
+    privcmd_gsi_from_irq_t gsi_irq = {
+        .irq = irq,
+        .gsi = -1,
+    };
+
+    if (ioctl(xcall->fd, IOCTL_PRIVCMD_GSI_FROM_IRQ, &gsi_irq)) {
+        PERROR("failed to get gsi from irq");
+        return -1;
+    }
+
+    return gsi_irq.gsi;
+}
+
 static void *alloc_pages_bufdev(xencall_handle *xcall, size_t npages)
 {
     void *p;
diff --git a/tools/libs/call/private.h b/tools/libs/call/private.h
index 9c3aa432efe2..2d86cfb1e099 100644
--- a/tools/libs/call/private.h
+++ b/tools/libs/call/private.h
@@ -57,6 +57,15 @@ int osdep_xencall_close(xencall_handle *xcall);
 
 long osdep_hypercall(xencall_handle *xcall, privcmd_hypercall_t *hypercall);
 
+#if defined(__linux__)
+long osdep_oscall(xencall_handle *xcall, int irq);
+#else
+static inline long osdep_oscall(xencall_handle *xcall, int irq)
+{
+    return -1;
+}
+#endif
+
 void *osdep_alloc_pages(xencall_handle *xcall, size_t nr_pages);
 void osdep_free_pages(xencall_handle *xcall, void *p, size_t nr_pages);
 
diff --git a/tools/libs/ctrl/xc_physdev.c b/tools/libs/ctrl/xc_physdev.c
index 460a8e779ce8..4d3b138ebd0e 100644
--- a/tools/libs/ctrl/xc_physdev.c
+++ b/tools/libs/ctrl/xc_physdev.c
@@ -111,3 +111,7 @@ int xc_physdev_unmap_pirq(xc_interface *xch,
     return rc;
 }
 
+int xc_physdev_gsi_from_irq(xc_interface *xch, int irq)
+{
+    return xen_oscall_gsi_from_irq(xch->xcall, irq);
+}
diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
index 96cb4da0794e..d4313e196ebd 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -1486,6 +1486,11 @@ static void pci_add_dm_done(libxl__egc *egc,
         goto out_no_irq;
     }
     if ((fscanf(f, "%u", &irq) == 1) && irq) {
+        /* if fail, keep using irq; if success, r is gsi, use gsi. */
+        r = xc_physdev_gsi_from_irq(ctx->xch, irq);
+        if (r != -1) {
+            irq = r;
+        }
         r = xc_physdev_map_pirq(ctx->xch, domid, irq, &irq);
         if (r < 0) {
             LOGED(ERROR, domainid, "xc_physdev_map_pirq irq=%d (error=%d)",
@@ -2174,6 +2179,7 @@ static void pci_remove_detached(libxl__egc *egc,
     FILE *f;
     uint32_t domainid = prs->domid;
     bool isstubdom;
+    int r;
 
     /* Convenience aliases */
     libxl_device_pci *const pci = &prs->pci;
@@ -2239,6 +2245,11 @@ skip_bar:
     }
 
     if ((fscanf(f, "%u", &irq) == 1) && irq) {
+        /* if fail, keep using irq; if success, r is gsi, use gsi. */
+        r = xc_physdev_gsi_from_irq(ctx->xch, irq);
+        if (r != -1) {
+            irq = r;
+        }
         rc = xc_physdev_unmap_pirq(ctx->xch, domid, irq);
         if (rc < 0) {
             /*
