[PATCH 1/1] vfio/platform: Add mmio-base property to define start address for MMIO mapping

[Juan Pablo Ruiz]

Some platform devices have large MMIO regions (e.g., GPU reserved memory). For
certain devices, it's preferable to have a 1:1 address translation in the VM to
avoid modifying driver source code.

This patch:

1. Increases the VFIO platform bus size from 32MB to 130GB.
2. Changes the mmio_size property from 32 to 64 bits.
3. Adds an mmio-base property to define the starting MMIO address for mapping
   the VFIO device.

Signed-off-by: Juan Pablo Ruiz juanpablo.ruiz@unikie.com
---
 hw/arm/virt.c                   |  6 +++---
 hw/core/platform-bus.c          | 28 ++++++++++++++++++++++++++--
 hw/vfio/platform.c              |  1 +
 include/hw/platform-bus.h       |  2 +-
 include/hw/vfio/vfio-platform.h |  1 +
 5 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 1a381e9a2b..9fc8f4425a 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -183,13 +183,13 @@ static const MemMapEntry base_memmap[] = {
     [VIRT_SECURE_GPIO] =        { 0x090b0000, 0x00001000 },
     [VIRT_MMIO] =               { 0x0a000000, 0x00000200 },
     /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size */
-    [VIRT_PLATFORM_BUS] =       { 0x0c000000, 0x02000000 },
+    [VIRT_PLATFORM_BUS] =       { 0x60000000, 0x1FC0000000 },          // 
130048MB
     [VIRT_SECURE_MEM] =         { 0x0e000000, 0x01000000 },
     [VIRT_PCIE_MMIO] =          { 0x10000000, 0x2eff0000 },
     [VIRT_PCIE_PIO] =           { 0x3eff0000, 0x00010000 },
     [VIRT_PCIE_ECAM] =          { 0x3f000000, 0x01000000 },
     /* Actual RAM size depends on initial RAM and device memory settings */
-    [VIRT_MEM] =                { GiB, LEGACY_RAMLIMIT_BYTES },
+    [VIRT_MEM] =                { 0x2000000000, LEGACY_RAMLIMIT_BYTES },
 };
 
 /*
@@ -1625,7 +1625,7 @@ static void create_platform_bus(VirtMachineState *vms)
     dev = qdev_new(TYPE_PLATFORM_BUS_DEVICE);
     dev->id = g_strdup(TYPE_PLATFORM_BUS_DEVICE);
     qdev_prop_set_uint32(dev, "num_irqs", PLATFORM_BUS_NUM_IRQS);
-    qdev_prop_set_uint32(dev, "mmio_size", 
vms->memmap[VIRT_PLATFORM_BUS].size);
+    qdev_prop_set_uint64(dev, "mmio_size", 
vms->memmap[VIRT_PLATFORM_BUS].size);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
     vms->platform_bus_dev = dev;
 
diff --git a/hw/core/platform-bus.c b/hw/core/platform-bus.c
index dc58bf505a..f545fab6e5 100644
--- a/hw/core/platform-bus.c
+++ b/hw/core/platform-bus.c
@@ -22,6 +22,7 @@
 #include "qemu/osdep.h"
 #include "hw/platform-bus.h"
 #include "hw/qdev-properties.h"
+#include "hw/vfio/vfio-platform.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
@@ -130,11 +131,29 @@ static void platform_bus_map_mmio(PlatformBusDevice 
*pbus, SysBusDevice *sbdev,
                                   int n)
 {
     MemoryRegion *sbdev_mr = sysbus_mmio_get_region(sbdev, n);
+    VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
     uint64_t size = memory_region_size(sbdev_mr);
     uint64_t alignment = (1ULL << (63 - clz64(size + size - 1)));
     uint64_t off;
+    uint64_t mmio_base_off;
     bool found_region = false;
 
+    if (vdev->mmio_base) {
+        if(vdev->mmio_base < pbus->mmio.addr || 
+           vdev->mmio_base >= pbus->mmio.addr + pbus->mmio_size){
+            error_report("Platform Bus: MMIO base 0x%"PRIx64
+                " outside platform bus region [0x%"PRIx64",0x%"PRIx64"]",
+                vdev->mmio_base,
+                pbus->mmio.addr,
+                pbus->mmio.addr + pbus->mmio_size);
+            exit(1);
+        }
+        
+        mmio_base_off = vdev->mmio_base - pbus->mmio.addr;
+    } else {
+        mmio_base_off = 0;
+    }
+    
     if (memory_region_is_mapped(sbdev_mr)) {
         /* Region is already mapped, nothing to do */
         return;
@@ -144,7 +163,7 @@ static void platform_bus_map_mmio(PlatformBusDevice *pbus, 
SysBusDevice *sbdev,
      * Look for empty space in the MMIO space that is naturally aligned with
      * the target device's memory region
      */
-    for (off = 0; off < pbus->mmio_size; off += alignment) {
+    for (off = mmio_base_off; off < pbus->mmio_size; off += alignment) {
         MemoryRegion *mr = memory_region_find(&pbus->mmio, off, size).mr;
         if (!mr) {
             found_region = true;
@@ -154,6 +173,11 @@ static void platform_bus_map_mmio(PlatformBusDevice *pbus, 
SysBusDevice *sbdev,
         }
     }
 
+    if (vdev->mmio_base && vdev->mmio_base != off + pbus->mmio.addr) {
+        warn_report("Platform Bus: Not able to map in mmio base: 0x%"PRIx64, 
+            vdev->mmio_base);
+    }
+
     if (!found_region) {
         error_report("Platform Bus: Can not fit MMIO region of size %"PRIx64,
                      size);
@@ -206,7 +230,7 @@ static void platform_bus_realize(DeviceState *dev, Error 
**errp)
 
 static Property platform_bus_properties[] = {
     DEFINE_PROP_UINT32("num_irqs", PlatformBusDevice, num_irqs, 0),
-    DEFINE_PROP_UINT32("mmio_size", PlatformBusDevice, mmio_size, 0),
+    DEFINE_PROP_UINT64("mmio_size", PlatformBusDevice, mmio_size, 0),
     DEFINE_PROP_END_OF_LIST()
 };
 
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index a85c199c76..cfac564093 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -640,6 +640,7 @@ static Property vfio_platform_dev_properties[] = {
     DEFINE_PROP_LINK("iommufd", VFIOPlatformDevice, vbasedev.iommufd,
                      TYPE_IOMMUFD_BACKEND, IOMMUFDBackend *),
 #endif
+    DEFINE_PROP_UINT64("mmio-base", VFIOPlatformDevice, mmio_base, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/platform-bus.h b/include/hw/platform-bus.h
index 44f30c5353..4e9913a5d7 100644
--- a/include/hw/platform-bus.h
+++ b/include/hw/platform-bus.h
@@ -34,7 +34,7 @@ struct PlatformBusDevice {
     SysBusDevice parent_obj;
 
     /*< public >*/
-    uint32_t mmio_size;
+    uint64_t mmio_size;
     MemoryRegion mmio;
 
     uint32_t num_irqs;
diff --git a/include/hw/vfio/vfio-platform.h b/include/hw/vfio/vfio-platform.h
index c414c3dffc..90575b5852 100644
--- a/include/hw/vfio/vfio-platform.h
+++ b/include/hw/vfio/vfio-platform.h
@@ -59,6 +59,7 @@ struct VFIOPlatformDevice {
     uint32_t mmap_timeout; /* delay to re-enable mmaps after interrupt */
     QEMUTimer *mmap_timer; /* allows fast-path resume after IRQ hit */
     QemuMutex intp_mutex; /* protect the intp_list IRQ state */
+    uint64_t mmio_base; /* base address to start looking for mmio */
     bool irqfd_allowed; /* debug option to force irqfd on/off */
 };
 typedef struct VFIOPlatformDevice VFIOPlatformDevice;
-- 
2.34.1