[Qemu-devel] [PATCH v2] spapr-pci: Enable huge BARs

[Alexey Kardashevskiy <aik@ozlabs.ru>]

At the moment sPAPR only supports 512MB window for MMIO BARs. However
modern devices might want bigger 64bit BARs.

This extends MMIO window from 512MB to 62GB (aligned to
SPAPR_PCI_WINDOW_SPACING) and advertises it in 2 records in
the PHB's "ranges" property. 32bit has all the space from
SPAPR_PCI_MEM_WIN_BUS_OFFSET till the end of 4GB, 64bit has the rest
of the window.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v2:
* do not change existing memory layout
* do not create another mmio window
---
 hw/ppc/spapr_pci.c          | 8 +++++++-
 include/hw/pci-host/spapr.h | 7 ++++---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 21b95b3..3641f87 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -862,6 +862,7 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
     int bus_off, i, j;
     char nodename[256];
     uint32_t bus_range[] = { cpu_to_be32(0), cpu_to_be32(0xff) };
+    const uint32_t win32size = (1ULL << 32) - SPAPR_PCI_MEM_WIN_BUS_OFFSET;
     struct {
         uint32_t hi;
         uint64_t child;
@@ -876,7 +877,12 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
         {
             cpu_to_be32(b_ss(2)), cpu_to_be64(SPAPR_PCI_MEM_WIN_BUS_OFFSET),
             cpu_to_be64(phb->mem_win_addr),
-            cpu_to_be64(memory_region_size(&phb->memwindow)),
+            cpu_to_be64(win32size),
+        },
+        {
+            cpu_to_be32(b_ss(3)), cpu_to_be64(1ULL << 32),
+            cpu_to_be64(phb->mem_win_addr + win32size),
+            cpu_to_be64(memory_region_size(&phb->memwindow) - win32size)
         },
     };
     uint64_t bus_reg[] = { cpu_to_be64(phb->buid), 0 };
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index 4ea2a0d..dc0d870 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -96,17 +96,18 @@ struct sPAPRPHBVFIOState {
 
 #define SPAPR_PCI_BASE_BUID          0x800000020000000ULL
 
+#define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
+
 #define SPAPR_PCI_WINDOW_BASE        0x10000000000ULL
 #define SPAPR_PCI_WINDOW_SPACING     0x1000000000ULL
 #define SPAPR_PCI_MMIO_WIN_OFF       0xA0000000
-#define SPAPR_PCI_MMIO_WIN_SIZE      0x20000000
+#define SPAPR_PCI_MMIO_WIN_SIZE      (0x1000000000ULL - \
+                                     SPAPR_PCI_MEM_WIN_BUS_OFFSET)
 #define SPAPR_PCI_IO_WIN_OFF         0x80000000
 #define SPAPR_PCI_IO_WIN_SIZE        0x10000
 
 #define SPAPR_PCI_MSI_WINDOW         0x40000000000ULL
 
-#define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
-
 static inline qemu_irq spapr_phb_lsi_qirq(struct sPAPRPHBState *phb, int pin)
 {
     return xics_get_qirq(spapr->icp, phb->lsi_table[pin].irq);
-- 
2.0.0