MSI: Robust resource release

msi_init may fail, so we need to check on uninit if the cap was
actually installed. This also avoids that the users need to check.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

3 files changed, 12 insertions, 9 deletions

diff --git a/hw/ide/ich.c b/hw/ide/ich.c
index eb00f03..fd3537e 100644
--- a/hw/ide/ich.c
+++ b/hw/ide/ich.c
@@ -110,10 +110,7 @@ static int pci_ich9_uninit(PCIDevice *dev)
     struct AHCIPCIState *d;
     d = DO_UPCAST(struct AHCIPCIState, card, dev);
 
-    if (msi_enabled(dev)) {
-        msi_uninit(dev);
-    }
-
+    msi_uninit(dev);
     qemu_unregister_reset(ahci_reset, d);
     ahci_uninit(&d->ahci);
 
diff --git a/hw/intel-hda.c b/hw/intel-hda.c
index 7f83745..5485745 100644
--- a/hw/intel-hda.c
+++ b/hw/intel-hda.c
@@ -1165,9 +1165,7 @@ static int intel_hda_exit(PCIDevice *pci)
 {
     IntelHDAState *d = DO_UPCAST(IntelHDAState, pci, pci);
 
-    if (d->msi) {
-        msi_uninit(&d->pci);
-    }
+    msi_uninit(&d->pci);
     cpu_unregister_io_memory(d->mmio_addr);
     return 0;
 }
diff --git a/hw/msi.c b/hw/msi.c
index 3dc3a24..b0795bd 100644
--- a/hw/msi.c
+++ b/hw/msi.c
@@ -164,9 +164,17 @@ int msi_init(struct PCIDevice *dev, uint8_t offset,
 
 void msi_uninit(struct PCIDevice *dev)
 {
-    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
-    uint8_t cap_size = msi_cap_sizeof(flags);
+    uint16_t flags;
+    uint8_t cap_size;
+
+    if (!(dev->cap_present & QEMU_PCI_CAP_MSI)) {
+        return;
+    }
+    flags = pci_get_word(dev->config + msi_flags_off(dev));
+    cap_size = msi_cap_sizeof(flags);
     pci_del_capability(dev, PCI_CAP_ID_MSIX, cap_size);
+    dev->cap_present &= ~QEMU_PCI_CAP_MSI;
+
     MSI_DEV_PRINTF(dev, "uninit\n");
 }