On Wed, Nov 13, 2024 at 10:57 AM Eric Auger <[email protected]> wrote:
>
> Hi Juan Pablo,
>
> On 11/13/24 00:43, Alex Williamson wrote:
> > On Tue, 12 Nov 2024 22:02:12 +0000
> > Juan Pablo Ruiz <[email protected]> wrote:
> >
> >> 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.
> > Why do we need 1:1 mappings? Shouldn't the device tree describe where
> > the device lives in the VM address space and the driver should adapt
> > rather than use hard coded addresses?
> >
> > How does a user know which devices need fixed base addresses and what
> > those addresses should be?
> >
> >> This patch:
> > ... should be split into at least 3 patches.
> >
> >> 1. Increases the VFIO platform bus size from 32MB to 130GB.
> > That's a very strange and specific size.
> >
> >> 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 [email protected]
> >> ---
> >> 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 },
> This won't be accepted. We had this discussion in the past with Peter
> (added in cc) and it is not possible to change the inital RAM layout
> like that.
>
> Thanks
>
> Eric
Thanks Eric, I will use another approach. I will try with the new SMMUv3 nested
translation support for DMA operations of passthrough platform GPUs.
Juan Pablo
> >> };
> >>
> >> /*
> >> @@ -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);
> > How do you know it's a vfio-platform device? This completely breaks
> > device abstraction. Thanks,
> >
> > Alex
> >
> >> 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;
>
