PPC: e500 pci host: Add support for ATMUs

The e500 PCI controller has configurable windows that allow a guest OS
to selectively map parts of the PCI bus space to CPU address space and
to selectively map parts of the CPU address space for DMA requests into
PCI visible address ranges.

So far, we've simply assumed that this mapping is 1:1 and ignored it.

However, the PCICSRBAR (CCSR mapped in PCI bus space) always has to live
inside the first 32bits of address space. This means if we always treat
all mappings as 1:1, this map will collide with our RAM map from the CPU's
point of view.

So this patch adds proper ATMU support which allows us to keep the PCICSRBAR
below 32bits local to the PCI bus and have another, different window to PCI
BARs at the upper end of address space. We leverage this on e500plat though,
mpc8544ds stays virtually 1:1 like it was before, but now also goes via ATMU.

With this patch, I can run guests with lots of RAM and not coincidently access
MSI-X mappings while I really want to access RAM.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 107 insertions, 6 deletions

diff --git a/hw/pci-host/ppce500.c b/hw/pci-host/ppce500.c
index 1b4c0f0023..574f8b2efb 100644
--- a/hw/pci-host/ppce500.c
+++ b/hw/pci-host/ppce500.c
@@ -62,11 +62,19 @@
 #define PPCE500_PCI_NR_POBS     5
 #define PPCE500_PCI_NR_PIBS     3
 
+#define PIWAR_EN                0x80000000      /* Enable */
+#define PIWAR_PF                0x20000000      /* prefetch */
+#define PIWAR_TGI_LOCAL         0x00f00000      /* target - local memory */
+#define PIWAR_READ_SNOOP        0x00050000
+#define PIWAR_WRITE_SNOOP       0x00005000
+#define PIWAR_SZ_MASK           0x0000003f
+
 struct  pci_outbound {
     uint32_t potar;
     uint32_t potear;
     uint32_t powbar;
     uint32_t powar;
+    MemoryRegion mem;
 };
 
 struct pci_inbound {
@@ -74,6 +82,7 @@ struct pci_inbound {
     uint32_t piwbar;
     uint32_t piwbear;
     uint32_t piwar;
+    MemoryRegion mem;
 };
 
 #define TYPE_PPC_E500_PCI_HOST_BRIDGE "e500-pcihost"
@@ -91,10 +100,13 @@ struct PPCE500PCIState {
     uint32_t irq_num[PCI_NUM_PINS];
     uint32_t first_slot;
     uint32_t first_pin_irq;
+    AddressSpace bm_as;
+    MemoryRegion bm;
     /* mmio maps */
     MemoryRegion container;
     MemoryRegion iomem;
     MemoryRegion pio;
+    MemoryRegion busmem;
 };
 
 #define TYPE_PPC_E500_PCI_BRIDGE "e500-host-bridge"
@@ -181,6 +193,71 @@ static uint64_t pci_reg_read4(void *opaque, hwaddr addr,
     return value;
 }
 
+/* DMA mapping */
+static void e500_update_piw(PPCE500PCIState *pci, int idx)
+{
+    uint64_t tar = ((uint64_t)pci->pib[idx].pitar) << 12;
+    uint64_t wbar = ((uint64_t)pci->pib[idx].piwbar) << 12;
+    uint64_t war = pci->pib[idx].piwar;
+    uint64_t size = 2ULL << (war & PIWAR_SZ_MASK);
+    MemoryRegion *address_space_mem = get_system_memory();
+    MemoryRegion *mem = &pci->pib[idx].mem;
+    MemoryRegion *bm = &pci->bm;
+    char *name;
+
+    if (memory_region_is_mapped(mem)) {
+        /* Before we modify anything, unmap and destroy the region */
+        memory_region_del_subregion(bm, mem);
+        object_unparent(OBJECT(mem));
+    }
+
+    if (!(war & PIWAR_EN)) {
+        /* Not enabled, nothing to do */
+        return;
+    }
+
+    name = g_strdup_printf("PCI Inbound Window %d", idx);
+    memory_region_init_alias(mem, OBJECT(pci), name, address_space_mem, tar,
+                             size);
+    memory_region_add_subregion_overlap(bm, wbar, mem, -1);
+    g_free(name);
+
+    pci_debug("%s: Added window of size=%#lx from PCI=%#lx to CPU=%#lx\n",
+              __func__, size, wbar, tar);
+}
+
+/* BAR mapping */
+static void e500_update_pow(PPCE500PCIState *pci, int idx)
+{
+    uint64_t tar = ((uint64_t)pci->pob[idx].potar) << 12;
+    uint64_t wbar = ((uint64_t)pci->pob[idx].powbar) << 12;
+    uint64_t war = pci->pob[idx].powar;
+    uint64_t size = 2ULL << (war & PIWAR_SZ_MASK);
+    MemoryRegion *mem = &pci->pob[idx].mem;
+    MemoryRegion *address_space_mem = get_system_memory();
+    char *name;
+
+    if (memory_region_is_mapped(mem)) {
+        /* Before we modify anything, unmap and destroy the region */
+        memory_region_del_subregion(address_space_mem, mem);
+        object_unparent(OBJECT(mem));
+    }
+
+    if (!(war & PIWAR_EN)) {
+        /* Not enabled, nothing to do */
+        return;
+    }
+
+    name = g_strdup_printf("PCI Outbound Window %d", idx);
+    memory_region_init_alias(mem, OBJECT(pci), name, &pci->busmem, tar,
+                             size);
+    memory_region_add_subregion(address_space_mem, wbar, mem);
+    g_free(name);
+
+    pci_debug("%s: Added window of size=%#lx from CPU=%#lx to PCI=%#lx\n",
+              __func__, size, wbar, tar);
+}
+
 static void pci_reg_write4(void *opaque, hwaddr addr,
                            uint64_t value, unsigned size)
 {
@@ -199,18 +276,22 @@ static void pci_reg_write4(void *opaque, hwaddr addr,
     case PPCE500_PCI_OW3:
     case PPCE500_PCI_OW4:
         idx = (addr >> 5) & 0x7;
-        switch (addr & 0xC) {
+        switch (addr & 0x1F) {
         case PCI_POTAR:
             pci->pob[idx].potar = value;
+            e500_update_pow(pci, idx);
             break;
         case PCI_POTEAR:
             pci->pob[idx].potear = value;
+            e500_update_pow(pci, idx);
             break;
         case PCI_POWBAR:
             pci->pob[idx].powbar = value;
+            e500_update_pow(pci, idx);
             break;
         case PCI_POWAR:
             pci->pob[idx].powar = value;
+            e500_update_pow(pci, idx);
             break;
         default:
             break;
@@ -221,18 +302,22 @@ static void pci_reg_write4(void *opaque, hwaddr addr,
     case PPCE500_PCI_IW2:
     case PPCE500_PCI_IW1:
         idx = ((addr >> 5) & 0x3) - 1;
-        switch (addr & 0xC) {
+        switch (addr & 0x1F) {
         case PCI_PITAR:
             pci->pib[idx].pitar = value;
+            e500_update_piw(pci, idx);
             break;
         case PCI_PIWBAR:
             pci->pib[idx].piwbar = value;
+            e500_update_piw(pci, idx);
             break;
         case PCI_PIWBEAR:
             pci->pib[idx].piwbear = value;
+            e500_update_piw(pci, idx);
             break;
         case PCI_PIWAR:
             pci->pib[idx].piwar = value;
+            e500_update_piw(pci, idx);
             break;
         default:
             break;
@@ -349,13 +434,20 @@ static int e500_pcihost_bridge_initfn(PCIDevice *d)
     return 0;
 }
 
+static AddressSpace *e500_pcihost_set_iommu(PCIBus *bus, void *opaque,
+                                            int devfn)
+{
+    PPCE500PCIState *s = opaque;
+
+    return &s->bm_as;
+}
+
 static int e500_pcihost_initfn(SysBusDevice *dev)
 {
     PCIHostState *h;
     PPCE500PCIState *s;
     PCIBus *b;
     int i;
-    MemoryRegion *address_space_mem = get_system_memory();
 
     h = PCI_HOST_BRIDGE(dev);
     s = PPC_E500_PCI_HOST_BRIDGE(dev);
@@ -369,12 +461,22 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
     }
 
     memory_region_init(&s->pio, OBJECT(s), "pci-pio", PCIE500_PCI_IOLEN);
+    memory_region_init(&s->busmem, OBJECT(s), "pci bus memory", UINT64_MAX);
+
+    /* PIO lives at the bottom of our bus space */
+    memory_region_add_subregion_overlap(&s->busmem, 0, &s->pio, -2);
 
     b = pci_register_bus(DEVICE(dev), NULL, mpc85xx_pci_set_irq,
-                         mpc85xx_pci_map_irq, s, address_space_mem,
-                         &s->pio, PCI_DEVFN(s->first_slot, 0), 4, TYPE_PCI_BUS);
+                         mpc85xx_pci_map_irq, s, &s->busmem, &s->pio,
+                         PCI_DEVFN(s->first_slot, 0), 4, TYPE_PCI_BUS);
     h->bus = b;
 
+    /* Set up PCI view of memory */
+    memory_region_init(&s->bm, OBJECT(s), "bm-e500", UINT64_MAX);
+    memory_region_add_subregion(&s->bm, 0x0, &s->busmem);
+    address_space_init(&s->bm_as, &s->bm, "pci-bm");
+    pci_setup_iommu(b, e500_pcihost_set_iommu, s);
+
     pci_create_simple(b, 0, "e500-host-bridge");
 
     memory_region_init(&s->container, OBJECT(h), "pci-container", PCIE500_ALL_SIZE);
@@ -388,7 +490,6 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
     memory_region_add_subregion(&s->container, PCIE500_CFGDATA, &h->data_mem);
     memory_region_add_subregion(&s->container, PCIE500_REG_BASE, &s->iomem);
     sysbus_init_mmio(dev, &s->container);
-    sysbus_init_mmio(dev, &s->pio);
     pci_bus_set_route_irq_fn(b, e500_route_intx_pin_to_irq);
 
     return 0;