[Qemu-devel] [PATCH qemu v10 08/14] spapr_pci: Do complete reset of DMA config when resetting PHB

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On a system reset, DMA configuration has to reset too. At the moment
it clears the table content. This is enough for the single table case
but with DDW, we will also have to disable all DMA windows except
the default one. Furthermore according to sPAPR, if the guest removed
the default window and created a huge one at the same zero offset on
a PCI bus, the reset handler has to recreate the default window with
the default properties (2GB big, 4K pages).

This reworks SPAPR PHB code to disable the existing DMA window on reset
and then configure and enable the default window.
Without DDW that means that the same window will be disabled and then
enabled with no other change in behaviour.

This changes the table creation to do it in one place in PHB (VFIO PHB
just inherits the behaviour from PHB). The actual table allocation is
done from the reset handler and this is where dma_init_window() is called.

This disables all DMA windows on a PHB reset. It does not make any
difference now as there is just one DMA window but it will later with DDW
patches.

This makes spapr_phb_dma_reset() and spapr_phb_dma_remove_window() public
as these will be used in DDW RTAS "ibm,reset-pe-dma-window" and
"ibm,remove-pe-dma-window" handlers later; the handlers will reside in
hw/ppc/spapr_rtas_ddw.c.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
Changes:
v9:
* as spapr_phb_vfio_reset() became not empty, this does not remove it but
adds spapr_phb_dma_reset() call
* added SPAPR_PCI_DMA_MAX_WINDOWS (was in
"spapr_pci/spapr_pci_vfio: Support Dynamic DMA Windows (DDW)")
* object_child_foreach() is replaced with explicit loop over DMA windows
as later in the patchset we will be doing same loop and there the order
will matter (small windows should be enumerated first)

v7:
* s'finish_realize'dma_init_window' in the commit log
* added details (initial clause about reuse was there :) )
why exactly spapr_phb_dma_remove_window is public
---
 hw/ppc/spapr_pci.c          | 42 +++++++++++++++++++++++++++++++++---------
 hw/ppc/spapr_pci_vfio.c     |  4 ++++
 include/hw/pci-host/spapr.h |  5 +++++
 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index e27ca15..00816b3 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -829,6 +829,35 @@ static int spapr_phb_dma_init_window(sPAPRPHBState *sphb,
     return 0;
 }
 
+int spapr_phb_dma_remove_window(sPAPRPHBState *sphb,
+                                sPAPRTCETable *tcet)
+{
+    spapr_tce_table_disable(tcet);
+
+    return 0;
+}
+
+int spapr_phb_dma_reset(sPAPRPHBState *sphb)
+{
+    int i;
+    sPAPRTCETable *tcet;
+    sPAPRPHBClass *spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
+
+    spc->dma_capabilities_update(sphb); /* Refresh @has_vfio status */
+
+    for (i = 0; i < SPAPR_PCI_DMA_MAX_WINDOWS; ++i) {
+        tcet = spapr_tce_find_by_liobn(SPAPR_PCI_LIOBN(sphb->index, i));
+        if (tcet) {
+            spapr_phb_dma_remove_window(sphb, tcet);
+        }
+    }
+
+    spc->dma_init_window(sphb, SPAPR_PCI_LIOBN(sphb->index, 0),
+                         SPAPR_TCE_PAGE_SHIFT, sphb->dma32_window_size);
+
+    return 0;
+}
+
 /* Macros to operate with address in OF binding to PCI */
 #define b_x(x, p, l)    (((x) & ((1<<(l))-1)) << (p))
 #define b_n(x)          b_x((x), 31, 1) /* 0 if relocatable */
@@ -1236,7 +1265,6 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
     SysBusDevice *s = SYS_BUS_DEVICE(dev);
     sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(s);
     PCIHostState *phb = PCI_HOST_BRIDGE(s);
-    sPAPRPHBClass *info = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(s);
     char *namebuf;
     int i;
     PCIBus *bus;
@@ -1397,14 +1425,6 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
             return;
     }
 
-    info->dma_capabilities_update(sphb);
-    info->dma_init_window(sphb, sphb->dma_liobn, SPAPR_TCE_PAGE_SHIFT,
-                          sphb->dma32_window_size);
-    tcet = spapr_tce_find_by_liobn(sphb->dma_liobn);
-    if (!tcet) {
-        error_setg(errp, "failed to create TCE table");
-        return;
-    }
     memory_region_add_subregion(&sphb->iommu_root, 0,
                                 spapr_tce_get_iommu(tcet));
 
@@ -1424,6 +1444,10 @@ static int spapr_phb_children_reset(Object *child, void *opaque)
 
 static void spapr_phb_reset(DeviceState *qdev)
 {
+    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(qdev);
+
+    spapr_phb_dma_reset(sphb);
+
     /* Reset the IOMMU state */
     object_child_foreach(OBJECT(qdev), spapr_phb_children_reset, NULL);
 }
diff --git a/hw/ppc/spapr_pci_vfio.c b/hw/ppc/spapr_pci_vfio.c
index 69d85ab..cf5483a 100644
--- a/hw/ppc/spapr_pci_vfio.c
+++ b/hw/ppc/spapr_pci_vfio.c
@@ -73,6 +73,10 @@ static void spapr_phb_vfio_eeh_reenable(sPAPRPHBVFIOState *svphb)
 
 static void spapr_phb_vfio_reset(DeviceState *qdev)
 {
+    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(qdev);
+
+    spapr_phb_dma_reset(sphb);
+
     /*
      * The PE might be in frozen state. To reenable the EEH
      * functionality on it will clean the frozen state, which
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index b6d5719..fff868e 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -123,6 +123,8 @@ struct sPAPRPHBVFIOState {
 
 #define SPAPR_PCI_DMA32_SIZE         0x40000000
 
+#define SPAPR_PCI_DMA_MAX_WINDOWS    1
+
 static inline qemu_irq spapr_phb_lsi_qirq(struct sPAPRPHBState *phb, int pin)
 {
     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
@@ -143,5 +145,8 @@ void spapr_pci_rtas_init(void);
 sPAPRPHBState *spapr_pci_find_phb(sPAPRMachineState *spapr, uint64_t buid);
 PCIDevice *spapr_pci_find_dev(sPAPRMachineState *spapr, uint64_t buid,
                               uint32_t config_addr);
+int spapr_phb_dma_remove_window(sPAPRPHBState *sphb,
+                                sPAPRTCETable *tcet);
+int spapr_phb_dma_reset(sPAPRPHBState *sphb);
 
 #endif /* __HW_SPAPR_PCI_H__ */
-- 
2.4.0.rc3.8.gfb3e7d5