pci: Cache the bus mastering status in the device

The cached is_master value is necessary to know if a device is
allowed to issue ATS/PRI requests or not as these operations do not go
through the master_enable memory region.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
Message-Id: <20250520071823.764266-7-clement.mathieu--drif@eviden.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index f5ab510697e76bbc3a1a1db453ba698f8628622b..1114ba85298be088f9a2fd28f3a43c6f87ca7b6a 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -128,6 +128,12 @@ static GSequence *pci_acpi_index_list(void)
     return used_acpi_index_list;
 }
 
+static void pci_set_master(PCIDevice *d, bool enable)
+{
+    memory_region_set_enabled(&d->bus_master_enable_region, enable);
+    d->is_master = enable; /* cache the status */
+}
+
 static void pci_init_bus_master(PCIDevice *pci_dev)
 {
     AddressSpace *dma_as = pci_device_iommu_address_space(pci_dev);
@@ -135,7 +141,7 @@ static void pci_init_bus_master(PCIDevice *pci_dev)
     memory_region_init_alias(&pci_dev->bus_master_enable_region,
                              OBJECT(pci_dev), "bus master",
                              dma_as->root, 0, memory_region_size(dma_as->root));
-    memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
+    pci_set_master(pci_dev, false);
     memory_region_add_subregion(&pci_dev->bus_master_container_region, 0,
                                 &pci_dev->bus_master_enable_region);
 }
@@ -804,9 +810,8 @@ static int get_pci_config_device(QEMUFile *f, void *pv, size_t size,
         pci_bridge_update_mappings(PCI_BRIDGE(s));
     }
 
-    memory_region_set_enabled(&s->bus_master_enable_region,
-                              pci_get_word(s->config + PCI_COMMAND)
-                              & PCI_COMMAND_MASTER);
+    pci_set_master(s, pci_get_word(s->config + PCI_COMMAND)
+                      & PCI_COMMAND_MASTER);
 
     g_free(config);
     return 0;
@@ -1787,9 +1792,8 @@ void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val_in, int
 
     if (ranges_overlap(addr, l, PCI_COMMAND, 2)) {
         pci_update_irq_disabled(d, was_irq_disabled);
-        memory_region_set_enabled(&d->bus_master_enable_region,
-                                  (pci_get_word(d->config + PCI_COMMAND)
-                                   & PCI_COMMAND_MASTER) && d->enabled);
+        pci_set_master(d, (pci_get_word(d->config + PCI_COMMAND) &
+                          PCI_COMMAND_MASTER) && d->enabled);
     }
 
     msi_write_config(d, addr, val_in, l);
@@ -3100,9 +3104,8 @@ void pci_set_enabled(PCIDevice *d, bool state)
 
     d->enabled = state;
     pci_update_mappings(d);
-    memory_region_set_enabled(&d->bus_master_enable_region,
-                              (pci_get_word(d->config + PCI_COMMAND)
-                               & PCI_COMMAND_MASTER) && d->enabled);
+    pci_set_master(d, (pci_get_word(d->config + PCI_COMMAND)
+                      & PCI_COMMAND_MASTER) && d->enabled);
     if (qdev_is_realized(&d->qdev)) {
         pci_device_reset(d);
     }

diff --git a/include/hw/pci/pci_device.h b/include/hw/pci/pci_device.h
index e41d95b0b06fda0050e437a8edbcbb5ff9b2ba38..eee03385686c6fa00e4177e32623cdcac79b6fda 100644 (file)
--- a/include/hw/pci/pci_device.h
+++ b/include/hw/pci/pci_device.h
@@ -90,6 +90,7 @@ struct PCIDevice {
     char name[64];
     PCIIORegion io_regions[PCI_NUM_REGIONS];
     AddressSpace bus_master_as;
+    bool is_master;
     MemoryRegion bus_master_container_region;
     MemoryRegion bus_master_enable_region;