[Qemu-devel] [PATCH 1/2] pci: track function accesses

["Michael S. Tsirkin" <mst@redhat.com>]

Set a flag when function is first accessed after system reset.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/pci.c      |   26 ++++++++++++++++++++++++++
 hw/pci.h      |    3 +++
 hw/pci_host.c |    2 ++
 3 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index b706e69..2aaa45e 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -407,6 +407,17 @@ static VMStateInfo vmstate_info_pci_irq_state = {
     .put  = put_pci_irq_state,
 };
 
+static const VMStateDescription pci_vmstate_accessed_since_reset ={
+    .name = "pci/accessed_since_reset",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField []) {
+        VMSTATE_BOOL(accessed_since_reset, PCIDevice),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_pci_device = {
     .name = "PCIDevice",
     .version_id = 2,
@@ -421,6 +432,12 @@ const VMStateDescription vmstate_pci_device = {
 				   vmstate_info_pci_irq_state,
 				   PCI_NUM_PINS * sizeof(int32_t)),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (VMStateSubsection[]) {
+        {
+            .vmsd = &pci_vmstate_accessed_since_reset,
+        },
+        VMSTATE_END_OF_LIST()
     }
 };
 
@@ -738,6 +755,12 @@ static void pci_config_free(PCIDevice *pci_dev)
     g_free(pci_dev->used);
 }
 
+static void pci_system_reset_fn(void *opaque)
+{
+    PCIDevice *dev = opaque;
+    dev->accessed_since_reset = false;
+}
+
 /* -1 for devfn means auto assign */
 static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
                                          const char *name, int devfn)
@@ -805,11 +828,14 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     bus->devices[devfn] = pci_dev;
     pci_dev->irq = qemu_allocate_irqs(pci_set_irq, pci_dev, PCI_NUM_PINS);
     pci_dev->version_id = 2; /* Current pci device vmstate version */
+    pci_dev->accessed_since_reset = false;
+    qemu_register_reset(pci_system_reset_fn, pci_dev);
     return pci_dev;
 }
 
 static void do_pci_unregister_device(PCIDevice *pci_dev)
 {
+    qemu_unregister_reset(pci_system_reset_fn, pci_dev);
     qemu_free_irqs(pci_dev->irq);
     pci_dev->bus->devices[pci_dev->devfn] = NULL;
     pci_config_free(pci_dev);
diff --git a/hw/pci.h b/hw/pci.h
index 8d0aa49..3fdd1dc 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -243,6 +243,9 @@ struct PCIDevice {
     bool has_rom;
     MemoryRegion rom;
     uint32_t rom_bar;
+
+    /* Cleared on first access after system reset */
+    bool accessed_since_reset;
 };
 
 void pci_register_bar(PCIDevice *pci_dev, int region_num,
diff --git a/hw/pci_host.c b/hw/pci_host.c
index 44c6c20..3019d72 100644
--- a/hw/pci_host.c
+++ b/hw/pci_host.c
@@ -51,6 +51,7 @@ void pci_host_config_write_common(PCIDevice *pci_dev, uint32_t addr,
                                   uint32_t limit, uint32_t val, uint32_t len)
 {
     assert(len <= 4);
+    pci_dev->accessed_since_reset = true;
     pci_dev->config_write(pci_dev, addr, val, MIN(len, limit - addr));
 }
 
@@ -58,6 +59,7 @@ uint32_t pci_host_config_read_common(PCIDevice *pci_dev, uint32_t addr,
                                      uint32_t limit, uint32_t len)
 {
     assert(len <= 4);
+    pci_dev->accessed_since_reset = true;
     return pci_dev->config_read(pci_dev, addr, MIN(len, limit - addr));
 }
 
-- 
1.7.9.111.gf3fb0