spapr_pci/spapr_pci_vfio: Support Dynamic DMA Windows (DDW)

This adds support for Dynamic DMA Windows (DDW) option defined by
the SPAPR specification which allows to have additional DMA window(s)

The "ddw" property is enabled by default on a PHB but for compatibility
the pseries-2.6 machine and older disable it.
This also creates a single DMA window for the older machines to
maintain backward migration.

This implements DDW for PHB with emulated and VFIO devices. The host
kernel support is required. The advertised IOMMU page sizes are 4K and
64K; 16M pages are supported but not advertised by default, in order to
enable them, the user has to specify "pgsz" property for PHB and
enable huge pages for RAM.

The existing linux guests try creating one additional huge DMA window
with 64K or 16MB pages and map the entire guest RAM to. If succeeded,
the guest switches to dma_direct_ops and never calls TCE hypercalls
(H_PUT_TCE,...) again. This enables VFIO devices to use the entire RAM
and not waste time on map/unmap later. This adds a "dma64_win_addr"
property which is a bus address for the 64bit window and by default
set to 0x800.0000.0000.0000 as this is what the modern POWER8 hardware
uses and this allows having emulated and VFIO devices on the same bus.

This adds 4 RTAS handlers:
* ibm,query-pe-dma-window
* ibm,create-pe-dma-window
* ibm,remove-pe-dma-window
* ibm,reset-pe-dma-window
These are registered from type_init() callback.

These RTAS handlers are implemented in a separate file to avoid polluting
spapr_iommu.c with PCI.

This changes sPAPRPHBState::dma_liobn to an array to allow 2 LIOBNs
and updates all references to dma_liobn. However this does not add
64bit LIOBN to the migration stream as in fact even 32bit LIOBN is
rather pointless there (as it is a PHB property and the management
software can/should pass LIOBNs via CLI) but we keep it for the backward
migration support.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 22 insertions, 2 deletions

diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index 288b89c..193631d 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -32,6 +32,8 @@
 #define SPAPR_PCI_HOST_BRIDGE(obj) \
     OBJECT_CHECK(sPAPRPHBState, (obj), TYPE_SPAPR_PCI_HOST_BRIDGE)
 
+#define SPAPR_PCI_DMA_MAX_WINDOWS    2
+
 typedef struct sPAPRPHBState sPAPRPHBState;
 
 typedef struct spapr_pci_msi {
@@ -56,7 +58,7 @@ struct sPAPRPHBState {
     hwaddr mem_win_addr, mem_win_size, io_win_addr, io_win_size;
     MemoryRegion memwindow, iowindow, msiwindow;
 
-    uint32_t dma_liobn;
+    uint32_t dma_liobn[SPAPR_PCI_DMA_MAX_WINDOWS];
     hwaddr dma_win_addr, dma_win_size;
     AddressSpace iommu_as;
     MemoryRegion iommu_root;
@@ -71,6 +73,10 @@ struct sPAPRPHBState {
     spapr_pci_msi_mig *msi_devs;
 
     QLIST_ENTRY(sPAPRPHBState) list;
+
+    bool ddw_enabled;
+    uint64_t page_size_mask;
+    uint64_t dma64_win_addr;
 };
 
 #define SPAPR_PCI_MAX_INDEX          255
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 4932555..2e2dd14 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -416,6 +416,16 @@ int spapr_allocate_irq_block(int num, bool lsi, bool msi);
 #define RTAS_OUT_NOT_AUTHORIZED                 -9002
 #define RTAS_OUT_SYSPARM_PARAM_ERROR            -9999
 
+/* DDW pagesize mask values from ibm,query-pe-dma-window */
+#define RTAS_DDW_PGSIZE_4K       0x01
+#define RTAS_DDW_PGSIZE_64K      0x02
+#define RTAS_DDW_PGSIZE_16M      0x04
+#define RTAS_DDW_PGSIZE_32M      0x08
+#define RTAS_DDW_PGSIZE_64M      0x10
+#define RTAS_DDW_PGSIZE_128M     0x20
+#define RTAS_DDW_PGSIZE_256M     0x40
+#define RTAS_DDW_PGSIZE_16G      0x80
+
 /* RTAS tokens */
 #define RTAS_TOKEN_BASE      0x2000
 
@@ -457,8 +467,12 @@ int spapr_allocate_irq_block(int num, bool lsi, bool msi);
 #define RTAS_IBM_SET_SLOT_RESET                 (RTAS_TOKEN_BASE + 0x23)
 #define RTAS_IBM_CONFIGURE_PE                   (RTAS_TOKEN_BASE + 0x24)
 #define RTAS_IBM_SLOT_ERROR_DETAIL              (RTAS_TOKEN_BASE + 0x25)
+#define RTAS_IBM_QUERY_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x26)
+#define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
+#define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
+#define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x26)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20