Re: [Qemu-devel] [PATCH v2 3/4] arm: Add PCIe host bridge in virt machine

[Claudio Fontana]

Hi Alexander,

thank you for the respin. I retested with the new mappings on OSv for AArch64,
and they show up ok in the guest.

Just a couple minor comments below, otherwise I think this is good.

On 21.01.2015 17:18, Alexander Graf wrote:
> Now that we have a working "generic" PCIe host bridge driver, we can plug
> it into ARMs virt machine to always have PCIe available to normal ARM VMs.
> 
> I've successfully managed to expose a Bochs VGA device, XHCI and an e1000
> into an AArch64 VM with this and they all lived happily ever after.
> 
> Signed-off-by: Alexander Graf <address@hidden>
> Tested-by: Claudio Fontana <address@hidden>
> 
> ---
> 
> Linux 3.19 only supports the generic PCIe host bridge driver for 32bit ARM
> systems. If you want to use it with AArch64 guests, please apply the following
> patch or wait until upstream cleaned up the code properly:
> 
>   http://csgraf.de/agraf/pci/pci-3.19.patch
> 
> v1 -> v2:
> 
>   - Add define for pci range types
>   - Remove mmio_window_size
>   - Use 4 PCI INTX IRQ lines
> ---
>  default-configs/arm-softmmu.mak |   2 +
>  hw/arm/virt.c                   | 112 
> ++++++++++++++++++++++++++++++++++++++--
>  include/sysemu/device_tree.h    |   9 ++++
>  3 files changed, 118 insertions(+), 5 deletions(-)
> 
> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
> index f3513fa..7671ee2 100644
> --- a/default-configs/arm-softmmu.mak
> +++ b/default-configs/arm-softmmu.mak
> @@ -82,6 +82,8 @@ CONFIG_ZYNQ=y
>  CONFIG_VERSATILE_PCI=y
>  CONFIG_VERSATILE_I2C=y
>  
> +CONFIG_PCI_GENERIC=y
> +
>  CONFIG_SDHCI=y
>  CONFIG_INTEGRATOR_DEBUG=y
>  
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 2353440..a727b4e 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -42,6 +42,7 @@
>  #include "exec/address-spaces.h"
>  #include "qemu/bitops.h"
>  #include "qemu/error-report.h"
> +#include "hw/pci-host/gpex.h"
>  
>  #define NUM_VIRTIO_TRANSPORTS 32
>  
> @@ -69,6 +70,7 @@ enum {
>      VIRT_MMIO,
>      VIRT_RTC,
>      VIRT_FW_CFG,
> +    VIRT_PCIE,
>  };
>  
>  typedef struct MemMapEntry {
> @@ -129,13 +131,14 @@ static const MemMapEntry a15memmap[] = {
>      [VIRT_FW_CFG] =     { 0x09020000, 0x0000000a },
>      [VIRT_MMIO] =       { 0x0a000000, 0x00000200 },
>      /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size 
> */
> -    /* 0x10000000 .. 0x40000000 reserved for PCI */
> +    [VIRT_PCIE] =       { 0x10000000, 0x30000000 },
>      [VIRT_MEM] =        { 0x40000000, 30ULL * 1024 * 1024 * 1024 },
>  };
>  
>  static const int a15irqmap[] = {
>      [VIRT_UART] = 1,
>      [VIRT_RTC] = 2,
> +    [VIRT_PCIE] = 3, /* ... to 6 */
>      [VIRT_MMIO] = 16, /* ...to 16 + NUM_VIRTIO_TRANSPORTS - 1 */
>  };
>  
> @@ -312,7 +315,7 @@ static void fdt_add_cpu_nodes(const VirtBoardInfo *vbi)
>      }
>  }
>  
> -static void fdt_add_gic_node(const VirtBoardInfo *vbi)
> +static uint32_t fdt_add_gic_node(const VirtBoardInfo *vbi)
>  {
>      uint32_t gic_phandle;
>  
> @@ -331,9 +334,11 @@ static void fdt_add_gic_node(const VirtBoardInfo *vbi)
>                                       2, vbi->memmap[VIRT_GIC_CPU].base,
>                                       2, vbi->memmap[VIRT_GIC_CPU].size);
>      qemu_fdt_setprop_cell(vbi->fdt, "/intc", "phandle", gic_phandle);
> +
> +    return gic_phandle;
>  }
>  
> -static void create_gic(const VirtBoardInfo *vbi, qemu_irq *pic)
> +static uint32_t create_gic(const VirtBoardInfo *vbi, qemu_irq *pic)
>  {
>      /* We create a standalone GIC v2 */
>      DeviceState *gicdev;
> @@ -380,7 +385,7 @@ static void create_gic(const VirtBoardInfo *vbi, qemu_irq 
> *pic)
>          pic[i] = qdev_get_gpio_in(gicdev, i);
>      }
>  
> -    fdt_add_gic_node(vbi);
> +    return fdt_add_gic_node(vbi);
>  }
>  
>  static void create_uart(const VirtBoardInfo *vbi, qemu_irq *pic)
> @@ -556,6 +561,100 @@ static void create_fw_cfg(const VirtBoardInfo *vbi)
>      g_free(nodename);
>  }
>  
> +static void create_pcie_irq_map(const VirtBoardInfo *vbi, uint32_t 
> gic_phandle,
> +                                int first_irq, const char *nodename)
> +{
> +    int devfn, pin;
> +    uint32_t full_irq_map[4 * 4 * 8] = { 0 };
> +    uint32_t *irq_map = full_irq_map;
> +
> +    for (devfn = 0; devfn <= 0x18; devfn+=0x8) {

devfn += 0x8 (spaces)

> +        for (pin = 0; pin < 4; pin++) {
> +            int irq_type = GIC_FDT_IRQ_TYPE_SPI;
> +            int irq_nr = first_irq + ((pin + PCI_SLOT(devfn)) % 
> PCI_NUM_PINS);
> +            int irq_level = GIC_FDT_IRQ_FLAGS_LEVEL_HI;
> +            int i;
> +
> +            uint32_t map[] = {
> +                devfn << 8, 0, 0,                           /* devfn */
> +                pin + 1,                                    /* PCI pin */
> +                gic_phandle, irq_type, irq_nr, irq_level }; /* GIC irq */
> +
> +            /* Convert map to big endian */
> +            for (i = 0; i < 8; i++) {
> +                irq_map[i] = cpu_to_be32(map[i]);
> +            }
> +            irq_map += 8;
> +        }
> +    }
> +
> +    qemu_fdt_setprop(vbi->fdt, nodename, "interrupt-map",
> +                     full_irq_map, sizeof(full_irq_map));
> +}

I raise again (? or maybe for the first time) the suggestion to add a comment 
like:

/* see the openfirmware specs at 
 * http://www.firmware.org/1275/practice/imap/imap0_9d.pdf
 */

and optionally also a reference to the linux host-generic-pci bindings:

/* see the linux Documentation about device tree bindings at:
 * 
https://www.kernel.org/doc/Documentation/devicetree/bindings/pci/host-generic-pci.txt
 */

Peter mentioned that the documentation there is not perfect, but at least it's 
a starting point for the reader to understand what's going on.

> +
> +static void create_pcie(const VirtBoardInfo *vbi, qemu_irq *pic,
> +                        uint32_t gic_phandle)
> +{
> +    hwaddr base = vbi->memmap[VIRT_PCIE].base;
> +    hwaddr size = vbi->memmap[VIRT_PCIE].size;
> +    hwaddr size_ioport = 64 * 1024;
> +    hwaddr size_ecam = PCIE_MMCFG_SIZE_MIN;
> +    hwaddr size_mmio = size - size_ecam - size_ioport;
> +    hwaddr base_mmio = base;
> +    hwaddr base_ioport = base_mmio + size_mmio;
> +    hwaddr base_ecam = base_ioport + size_ioport;
> +    int irq = vbi->irqmap[VIRT_PCIE];
> +    MemoryRegion *mmio_alias;
> +    MemoryRegion *mmio_reg;
> +    DeviceState *dev;
> +    char *nodename;
> +    int i;
> +
> +    dev = qdev_create(NULL, TYPE_GPEX_HOST);
> +    qdev_init_nofail(dev);
> +
> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base_ecam);
> +    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, base_ioport);
> +
> +    /* Map the MMIO window at the same spot in bus and cpu layouts */
> +    mmio_alias = g_new0(MemoryRegion, 1);
> +    mmio_reg = sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 1);
> +    memory_region_init_alias(mmio_alias, OBJECT(dev), "pcie-mmio",
> +                             mmio_reg, base_mmio, size_mmio);
> +    memory_region_add_subregion(get_system_memory(), base_mmio, mmio_alias);
> +
> +    for (i = 0; i < 4; i++) {
> +        sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, pic[irq + i]);
> +    }
> +
> +    nodename = g_strdup_printf("/address@hidden" PRIx64, base);
> +    qemu_fdt_add_subnode(vbi->fdt, nodename);
> +    qemu_fdt_setprop_string(vbi->fdt, nodename,
> +                            "compatible", "pci-host-ecam-generic");
> +    qemu_fdt_setprop_string(vbi->fdt, nodename, "device_type", "pci");
> +    qemu_fdt_setprop_cell(vbi->fdt, nodename, "#address-cells", 3);
> +    qemu_fdt_setprop_cell(vbi->fdt, nodename, "#size-cells", 2);
> +    qemu_fdt_setprop_cells(vbi->fdt, nodename, "bus-range", 0, 1);
> +
> +    qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",
> +                                 2, base_ecam, 2, size_ecam);
> +    qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "ranges",
> +                                 1, FDT_PCI_RANGE_IOPORT, 2, 0,
> +                                 2, base_ioport, 2, size_ioport,
> +
> +                                 1, FDT_PCI_RANGE_MMIO, 2, base_mmio,
> +                                 2, base_mmio, 2, size_mmio);
> +
> +    qemu_fdt_setprop_cell(vbi->fdt, nodename, "#interrupt-cells", 1);
> +    create_pcie_irq_map(vbi, gic_phandle, irq, nodename);
> +
> +    qemu_fdt_setprop_cells(vbi->fdt, nodename, "interrupt-map-mask",
> +                           0x1800, 0, 0, /* devfn (PCI_SLOT(3)) */
> +                           0x7           /* PCI irq */);
> +
> +    g_free(nodename);
> +}
> +
>  static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)
>  {
>      const VirtBoardInfo *board = (const VirtBoardInfo *)binfo;
> @@ -573,6 +672,7 @@ static void machvirt_init(MachineState *machine)
>      MemoryRegion *ram = g_new(MemoryRegion, 1);
>      const char *cpu_model = machine->cpu_model;
>      VirtBoardInfo *vbi;
> +    uint32_t gic_phandle;
>  
>      if (!cpu_model) {
>          cpu_model = "cortex-a15";
> @@ -634,12 +734,14 @@ static void machvirt_init(MachineState *machine)
>  
>      create_flash(vbi);
>  
> -    create_gic(vbi, pic);
> +    gic_phandle = create_gic(vbi, pic);
>  
>      create_uart(vbi, pic);
>  
>      create_rtc(vbi, pic);
>  
> +    create_pcie(vbi, pic, gic_phandle);
> +
>      /* Create mmio transports, so the user can create virtio backends
>       * (which will be automatically plugged in to the transports). If
>       * no backend is created the transport will just sit harmlessly idle.
> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
> index 899f05c..979169b 100644
> --- a/include/sysemu/device_tree.h
> +++ b/include/sysemu/device_tree.h
> @@ -110,4 +110,13 @@ int qemu_fdt_setprop_sized_cells_from_array(void *fdt,
>                                                  qdt_tmp);                 \
>      })
>  
> +#define FDT_PCI_RANGE_RELOCATABLE          0x80000000
> +#define FDT_PCI_RANGE_PREFETCHABLE         0x40000000
> +#define FDT_PCI_RANGE_ALIASED              0x20000000
> +#define FDT_PCI_RANGE_TYPE                 0x03000000
> +#define FDT_PCI_RANGE_MMIO_64BIT           0x03000000
> +#define FDT_PCI_RANGE_MMIO                 0x02000000
> +#define FDT_PCI_RANGE_IOPORT               0x01000000
> +#define FDT_PCI_RANGE_CONFIG               0x00000000
> +
>  #endif /* __DEVICE_TREE_H__ */
> 

I appreciate those defines.

Thank you,

Claudio