[PATCH ats_vtd v2 10/25] pcie: helper functions to check if PASID and ATS are enabled

[CLEMENT MATHIEU--DRIF <clement.mathieu--drif@eviden.com>]

ats_enabled and pasid_enabled check whether the capabilities are
present or not. If so, we read the configuration space to get
the status of the feature (enabled or not).

Signed-off-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
---
 hw/pci/pcie.c         | 18 ++++++++++++++++++
 include/hw/pci/pcie.h |  3 +++
 2 files changed, 21 insertions(+)

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index d6a052b616..4efd84fed5 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -1201,3 +1201,21 @@ void pcie_pasid_init(PCIDevice *dev, uint16_t offset, uint8_t pasid_width,
 
     dev->exp.pasid_cap = offset;
 }
+
+bool pcie_pasid_enabled(const PCIDevice *dev)
+{
+    if (!pci_is_express(dev) || !dev->exp.pasid_cap) {
+        return false;
+    }
+    return (pci_get_word(dev->config + dev->exp.pasid_cap + PCI_PASID_CTRL) &
+                PCI_PASID_CTRL_ENABLE) != 0;
+}
+
+bool pcie_ats_enabled(const PCIDevice *dev)
+{
+    if (!pci_is_express(dev) || !dev->exp.ats_cap) {
+        return false;
+    }
+    return (pci_get_word(dev->config + dev->exp.ats_cap + PCI_ATS_CTRL) &
+                PCI_ATS_CTRL_ENABLE) != 0;
+}
diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
index c59627d556..8c222f09da 100644
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -151,4 +151,7 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
 
 void pcie_pasid_init(PCIDevice *dev, uint16_t offset, uint8_t pasid_width,
                      bool exec_perm, bool priv_mod);
+
+bool pcie_pasid_enabled(const PCIDevice *dev);
+bool pcie_ats_enabled(const PCIDevice *dev);
 #endif /* QEMU_PCIE_H */
-- 
2.44.0