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Re: [PATCH qemu v5] spapr: Kill SLOF


From: David Gibson
Subject: Re: [PATCH qemu v5] spapr: Kill SLOF
Date: Tue, 21 Jan 2020 16:11:00 +1100

On Fri, Jan 10, 2020 at 01:09:25PM +1100, Alexey Kardashevskiy wrote:
> The Petitboot bootloader is way more advanced than SLOF is ever going to
> be as Petitboot comes with the full-featured Linux kernel with all
> the drivers, and initramdisk with quite user friendly interface.
> The problem with ditching SLOF is that an unmodified pseries kernel can
> either start via:
> 1. kexec, this requires presence of RTAS and skips
> ibm,client-architecture-support entirely;
> 2. normal boot, this heavily relies on the OF1275 client interface to
> fetch the device tree and do early setup (claim memory).
> 
> This adds a new bios-less mode to the pseries machine: "bios=on|off".
> When enabled, QEMU does not load SLOF and jumps to the kernel from
> "-kernel".

I don't love the name "bios" for this flag, since BIOS tends to refer
to old-school x86 firmware.  Given the various plans we're considering
the future, I'd suggest "firmware=slof" for the current in-guest SLOF
mode, and say "firmware=vof" (Virtual Open Firmware) for the new
model.  We can consider firmware=petitboot or firmware=none (for
direct kexec-style boot into -kernel) or whatever in the future

> The client interface is implemented exactly as RTAS - a 20 bytes blob,
> right next after the RTAS blob. The entry point is passed to the kernel
> via GPR5.
> 
> This implements a handful of client interface methods just to get going.
> In particular, this implements the device tree fetching,
> ibm,client-architecture-support and instantiate-rtas.
> 
> This implements changing FDT properties for RTAS (for vmlinux and zImage)
> and initramdisk location (for zImage). To make this work, this skips
> fdt_pack() when bios=off as not packing the blob leaves some room for
> appending.
> 
> This assigns "phandles" to device tree nodes as there is no more SLOF
> and OF nodes addresses of which served as phandle values.
> This keeps predefined nodes (such as XICS/NVLINK/...) unchanged.
> phandles are regenerated at every FDT rebuild.
> 
> When bios=off, this adds "/chosen" every time QEMU builds a tree.
> 
> This implements "claim" which the client (Linux) uses for memory
> allocation; this is also  used by QEMU for claiming kernel/initrd images,
> client interface entry point, RTAS and the initial stack.
> 
> While at this, add a "kernel-addr" machine parameter to allow moving
> the kernel in memory. This is useful for debugging if the kernel is
> loaded at @0, although not necessary.
> 
> This adds basic instances support which are managed by a hashmap
> ihandle->[phandle, DeviceState, Chardev].
> 
> Note that a 64bit PCI fix is required for Linux:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=df5be5be8735e
> 
> The test command line:
> 
> qemu-system-ppc64 \
> -nodefaults \
> -chardev stdio,id=STDIO0,signal=off,mux=on \
> -device spapr-vty,id=svty0,reg=0x71000110,chardev=STDIO0 \
> -mon id=MON0,chardev=STDIO0,mode=readline \
> -nographic \
> -vga none \
> -kernel pbuild/kernel-le-guest/arch/powerpc/boot/zImage.pseries \
> -machine pseries,bios=off,cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken \
> -m 4G \
> -enable-kvm \
> -initrd pb/rootfs.cpio.xz \
> -device nec-usb-xhci,id=nec-usb-xhci0 \
> -netdev tap,id=TAP0,helper=/home/aik/qemu-bridge-helper --br=br0 \
> -device virtio-net-pci,id=vnet0,netdev=TAP0 img/f30le.qcow2 \
> -snapshot \
> -smp 8,threads=8 \
> -trace events=qemu_trace_events \
> -d guest_errors \
> -chardev socket,id=SOCKET0,server,nowait,path=qemu.mon.ssh54088 \
> -mon chardev=SOCKET0,mode=control
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>

It'd be nice to split this patch up a bit, though I'll admit it's not
very obvious where to do so.

> ---
> Changes:
> v5:
> * made instances keep device and chardev pointers
> * removed VIO dependencies
> * print error if RTAS memory is not claimed as it should have been
> * pack FDT as "quiesce"
> 
> v4:
> * fixed open
> * validate ihandles in "call-method"
> 
> v3:
> * fixed phandles allocation
> * s/__be32/uint32_t/ as we do not normally have __be32 type in qemu
> * fixed size of /chosen/stdout
> * bunch of renames
> * do not create rtas properties at all, let the client deal with it;
> instead setprop allows changing these in the FDT
> * no more packing FDT when bios=off - nobody needs it and getprop does not
> work otherwise
> * allow updating initramdisk device tree properties (for zImage)
> * added instances
> * fixed stdout on OF's "write"
> * removed special handling for stdout in OF client, spapr-vty handles it
> instead
> 
> v2:
> * fixed claim()
> * added "setprop"
> * cleaner client interface and RTAS blobs management
> * boots to petitboot and further to the target system
> * more trace points
> ---
>  hw/ppc/Makefile.objs     |   1 +
>  include/hw/ppc/spapr.h   |  28 +-
>  hw/ppc/spapr.c           | 266 ++++++++++++++--
>  hw/ppc/spapr_hcall.c     |  74 +++--
>  hw/ppc/spapr_of_client.c | 633 +++++++++++++++++++++++++++++++++++++++
>  hw/ppc/trace-events      |  12 +
>  6 files changed, 959 insertions(+), 55 deletions(-)
>  create mode 100644 hw/ppc/spapr_of_client.c
> 
> diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
> index 101e9fc59185..20efc0aa6f9b 100644
> --- a/hw/ppc/Makefile.objs
> +++ b/hw/ppc/Makefile.objs
> @@ -6,6 +6,7 @@ obj-$(CONFIG_PSERIES) += spapr_hcall.o spapr_iommu.o 
> spapr_rtas.o
>  obj-$(CONFIG_PSERIES) += spapr_pci.o spapr_rtc.o spapr_drc.o
>  obj-$(CONFIG_PSERIES) += spapr_cpu_core.o spapr_ovec.o spapr_irq.o
>  obj-$(CONFIG_PSERIES) += spapr_tpm_proxy.o
> +obj-$(CONFIG_PSERIES) += spapr_of_client.o
>  obj-$(CONFIG_SPAPR_RNG) +=  spapr_rng.o
>  # IBM PowerNV
>  obj-$(CONFIG_POWERNV) += pnv.o pnv_xscom.o pnv_core.o pnv_lpc.o pnv_psi.o 
> pnv_occ.o pnv_bmc.o
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 61f005c6f686..efc2c70abf99 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -105,6 +105,11 @@ struct SpaprCapabilities {
>      uint8_t caps[SPAPR_CAP_NUM];
>  };
>  
> +typedef struct {
> +    uint64_t start;
> +    uint64_t size;
> +} SpaprOfClaimed;
> +

Can we split more of the fake-OF code into a new file?

>  /**
>   * SpaprMachineClass:
>   */
> @@ -160,6 +165,13 @@ struct SpaprMachineState {
>      void *fdt_blob;
>      long kernel_size;
>      bool kernel_le;
> +    uint64_t kernel_addr;
> +    bool bios_enabled;
> +    uint32_t rtas_base;
> +    GArray *claimed; /* array of SpaprOfClaimed */
> +    uint64_t claimed_base;
> +    GHashTable *of_instances; /* ihandle -> SpaprOfInstance */
> +    uint32_t of_instance_last;
>      uint32_t initrd_base;
>      long initrd_size;
>      uint64_t rtc_offset; /* Now used only during incoming migration */
> @@ -510,7 +522,8 @@ struct SpaprMachineState {
>  /* Client Architecture support */
>  #define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
>  #define KVMPPC_H_UPDATE_DT      (KVMPPC_HCALL_BASE + 0x3)
> -#define KVMPPC_HCALL_MAX        KVMPPC_H_UPDATE_DT
> +#define KVMPPC_H_CLIENT         (KVMPPC_HCALL_BASE + 0x5)
> +#define KVMPPC_HCALL_MAX        KVMPPC_H_CLIENT
>  
>  /*
>   * The hcall range 0xEF00 to 0xEF80 is reserved for use in facilitating
> @@ -538,6 +551,11 @@ void spapr_register_hypercall(target_ulong opcode, 
> spapr_hcall_fn fn);
>  target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode,
>                               target_ulong *args);
>  
> +target_ulong do_client_architecture_support(PowerPCCPU *cpu,
> +                                            SpaprMachineState *spapr,
> +                                            target_ulong addr,
> +                                            target_ulong fdt_bufsize);
> +
>  /* Virtual Processor Area structure constants */
>  #define VPA_MIN_SIZE           640
>  #define VPA_SIZE_OFFSET        0x4
> @@ -769,6 +787,11 @@ struct SpaprEventLogEntry {
>  void *spapr_build_fdt(SpaprMachineState *spapr, bool reset, size_t space);
>  void spapr_events_init(SpaprMachineState *sm);
>  void spapr_dt_events(SpaprMachineState *sm, void *fdt);
> +uint64_t spapr_do_of_client_claim(SpaprMachineState *spapr, uint64_t virt,
> +                                  uint64_t size, uint64_t align);
> +
> +uint32_t spapr_of_client_open(SpaprMachineState *spapr, const char *path);
> +int spapr_h_client(SpaprMachineState *spapr, target_ulong client_args);
>  void close_htab_fd(SpaprMachineState *spapr);
>  void spapr_setup_hpt_and_vrma(SpaprMachineState *spapr);
>  void spapr_free_hpt(SpaprMachineState *spapr);
> @@ -891,4 +914,7 @@ void spapr_check_pagesize(SpaprMachineState *spapr, 
> hwaddr pagesize,
>  #define SPAPR_OV5_XIVE_BOTH     0x80 /* Only to advertise on the platform */
>  
>  void spapr_set_all_lpcrs(target_ulong value, target_ulong mask);
> +
> +void spapr_instantiate_rtas(SpaprMachineState *spapr, uint32_t base);
> +
>  #endif /* HW_SPAPR_H */
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index e62c89b3dd40..76ce8b973082 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -896,6 +896,55 @@ out:
>      return ret;
>  }
>  
> +/*
> + * Below is a compiled version of RTAS blob and OF client interface entry 
> point.
> + *
> + * gcc -nostdlib  -mbig -o spapr-rtas.img spapr-rtas.S
> + * objcopy  -O binary -j .text  spapr-rtas.img spapr-rtas.bin
> + *
> + *   .globl  _start
> + *   _start:
> + *           mr      4,3
> + *           lis     3,KVMPPC_H_RTAS@h
> + *           ori     3,3,KVMPPC_H_RTAS@l
> + *           sc      1
> + *           blr
> + *           mr      4,3
> + *           lis     3,KVMPPC_H_CLIENT@h
> + *           ori     3,3,KVMPPC_H_CLIENT@l
> + *           sc      1
> + *           blr
> + */
> +static struct {

Should be able to add a 'const' here.

> +    uint8_t rtas[20], client[20];
> +} QEMU_PACKED rtas_client_blob = {
> +    .rtas = {
> +        0x7c, 0x64, 0x1b, 0x78,
> +        0x3c, 0x60, 0x00, 0x00,
> +        0x60, 0x63, 0xf0, 0x00,
> +        0x44, 0x00, 0x00, 0x22,
> +        0x4e, 0x80, 0x00, 0x20
> +    },
> +    .client = {
> +        0x7c, 0x64, 0x1b, 0x78,
> +        0x3c, 0x60, 0x00, 0x00,
> +        0x60, 0x63, 0xf0, 0x05,
> +        0x44, 0x00, 0x00, 0x22,
> +        0x4e, 0x80, 0x00, 0x20
> +    }
> +};

I'd split this into two variables - there's not really any connection
between the two, AFAICT.

Note that I'm getting closer to merging the fwnmi stuff at which point
you'll need to pad the RTAS blob with a bunch of extra space for
taking the fwnmi dumps.

> +
> +void spapr_instantiate_rtas(SpaprMachineState *spapr, uint32_t base)
> +{
> +    if (spapr_do_of_client_claim(spapr, base, sizeof(rtas_client_blob.rtas),
> +                                 0) != -1) {

Wait.. == -1 is the success case?  That's a very surprising interface.

> +        error_report("The OF client did not claim RTAS memory at 0x%x", 
> base);

Error message is hard to follow.  Maybe "Could not claim memory for RTAS"

> +    }
> +    spapr->rtas_base = base;
> +    cpu_physical_memory_write(base, rtas_client_blob.rtas,
> +                              sizeof(rtas_client_blob.rtas));
> +}
> +
>  static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
>  {
>      MachineState *ms = MACHINE(spapr);
> @@ -980,6 +1029,11 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, 
> void *fdt)
>      _FDT(fdt_setprop(fdt, rtas, "ibm,lrdr-capacity",
>                       lrdr_capacity, sizeof(lrdr_capacity)));
>  
> +    if (!spapr->bios_enabled) {
> +        _FDT(fdt_setprop_cell(fdt, rtas, "rtas-size",
> +                              sizeof(rtas_client_blob.rtas)));
> +    }
> +
>      spapr_dt_rtas_tokens(fdt, rtas);
>  }
>  
> @@ -1057,7 +1111,7 @@ static void spapr_dt_chosen(SpaprMachineState *spapr, 
> void *fdt)
>      }
>  
>      if (spapr->kernel_size) {
> -        uint64_t kprop[2] = { cpu_to_be64(KERNEL_LOAD_ADDR),
> +        uint64_t kprop[2] = { cpu_to_be64(spapr->kernel_addr),

Hrm, I really think I would like to see the change to adjustable
kernel_addr split out - it puts a bunch of noise into the main kill
slof patch.

>                                cpu_to_be64(spapr->kernel_size) };
>  
>          _FDT(fdt_setprop(fdt, chosen, "qemu,boot-kernel",
> @@ -1245,7 +1299,8 @@ void *spapr_build_fdt(SpaprMachineState *spapr, bool 
> reset, size_t space)
>      /* Build memory reserve map */
>      if (reset) {
>          if (spapr->kernel_size) {
> -            _FDT((fdt_add_mem_rsv(fdt, KERNEL_LOAD_ADDR, 
> spapr->kernel_size)));
> +            _FDT((fdt_add_mem_rsv(fdt, spapr->kernel_addr,
> +                                  spapr->kernel_size)));
>          }
>          if (spapr->initrd_size) {
>              _FDT((fdt_add_mem_rsv(fdt, spapr->initrd_base,
> @@ -1268,12 +1323,56 @@ void *spapr_build_fdt(SpaprMachineState *spapr, bool 
> reset, size_t space)
>          }
>      }
>  
> +    if (!spapr->bios_enabled) {
> +        uint32_t phandle;
> +        int i, offset, proplen = 0;
> +        const void *prop;
> +        bool found = false;
> +        GArray *phandles = g_array_new(false, false, sizeof(uint32_t));
> +
> +        /* Find all predefined phandles */
> +        for (offset = fdt_next_node(fdt, -1, NULL);
> +             offset >= 0;
> +             offset = fdt_next_node(fdt, offset, NULL)) {
> +            prop = fdt_getprop_namelen(fdt, offset, "phandle", 7, &proplen);

You can just use fdt_getprop() rather than the namelen variant (that's
only really useful when you don't have a \0-terminated string with the
name).

> +            if (prop && proplen == sizeof(uint32_t)) {
> +                phandle = fdt32_ld(prop);
> +                g_array_append_val(phandles, phandle);
> +            }
> +        }
> +
> +        /* Assign phandles skipping the predefined ones */
> +        for (offset = fdt_next_node(fdt, -1, NULL), phandle = 1;
> +             offset >= 0;
> +             offset = fdt_next_node(fdt, offset, NULL), ++phandle) {
> +            prop = fdt_getprop_namelen(fdt, offset, "phandle", 7, &proplen);
> +            if (prop) {
> +                continue;
> +            }
> +            /* Check if the current phandle is not allocated already */
> +            for ( ; ; ++phandle) {
> +                for (i = 0, found = false; i < phandles->len; ++i) {
> +                    if (phandle == g_array_index(phandles, uint32_t, i)) {
> +                        found = true;
> +                        break;
> +                    }
> +                }
> +                if (!found) {
> +                    break;
> +                }
> +            }
> +            _FDT(fdt_setprop_cell(fdt, offset, "phandle", phandle));
> +        }
> +        g_array_unref(phandles);
> +    }
> +
>      return fdt;
>  }
>  
>  static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
>  {
> -    return (addr & 0x0fffffff) + KERNEL_LOAD_ADDR;
> +    SpaprMachineState *spapr = opaque;
> +    return (addr & 0x0fffffff) + spapr->kernel_addr;
>  }
>  
>  static void emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
> @@ -1660,24 +1759,89 @@ static void spapr_machine_reset(MachineState *machine)
>       */
>      fdt_addr = MIN(spapr->rma_size, RTAS_MAX_ADDR) - FDT_MAX_SIZE;
>  
> +    /* Set up the entry state */
> +    if (!spapr->bios_enabled) {
> +        if (spapr->claimed) {
> +            g_array_unref(spapr->claimed);
> +        }
> +        if (spapr->of_instances) {
> +            g_hash_table_unref(spapr->of_instances);
> +        }
> +
> +        spapr->claimed = g_array_new(false, false, sizeof(SpaprOfClaimed));
> +        spapr->of_instances = g_hash_table_new(g_direct_hash, 
> g_direct_equal);
> +
> +        spapr->claimed_base = 0x10000; /* Avoid using the first system page 
> */
> +
> +        spapr_cpu_set_entry_state(first_ppc_cpu, spapr->kernel_addr,
> +                                  spapr->initrd_base);
> +        first_ppc_cpu->env.gpr[4] = spapr->initrd_size;
> +
> +        if (spapr_do_of_client_claim(spapr, spapr->kernel_addr,
> +                                  spapr->kernel_size, 0) == -1) {
> +            error_report("Memory for kernel is in use");
> +            exit(1);
> +        }
> +        if (spapr_do_of_client_claim(spapr, spapr->initrd_base,
> +                                  spapr->initrd_size, 0) == -1) {
> +            error_report("Memory for initramdisk is in use");
> +            exit(1);
> +        }
> +        first_ppc_cpu->env.gpr[1] = spapr_do_of_client_claim(spapr, 0, 
> 0x40000,
> +                                                             0x10000);
> +        if (first_ppc_cpu->env.gpr[1] == -1) {
> +            error_report("Memory allocation for stack failed");
> +            exit(1);
> +        }
> +
> +        first_ppc_cpu->env.gpr[5] =
> +            spapr_do_of_client_claim(spapr, 0, 
> sizeof(rtas_client_blob.client),
> +                                     sizeof(rtas_client_blob.client));
> +        if (first_ppc_cpu->env.gpr[5] == -1) {
> +            error_report("Memory allocation for OF client failed");
> +            exit(1);
> +        }
> +        cpu_physical_memory_write(first_ppc_cpu->env.gpr[5],
> +                                  rtas_client_blob.client,
> +                                  sizeof(rtas_client_blob.client));
> +    } else {
> +        spapr_cpu_set_entry_state(first_ppc_cpu, SPAPR_ENTRY_POINT, 
> fdt_addr);
> +        first_ppc_cpu->env.gpr[5] = 0; /* 0 = kexec !0 = prom_init */
> +    }
> +
>      fdt = spapr_build_fdt(spapr, true, FDT_MAX_SIZE);
>  
> -    rc = fdt_pack(fdt);
> -
> -    /* Should only fail if we've built a corrupted tree */
> -    assert(rc == 0);
> -
> -    /* Load the fdt */
> -    qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> -    cpu_physical_memory_write(fdt_addr, fdt, fdt_totalsize(fdt));
>      g_free(spapr->fdt_blob);
>      spapr->fdt_size = fdt_totalsize(fdt);
>      spapr->fdt_initial_size = spapr->fdt_size;
>      spapr->fdt_blob = fdt;
>  
> -    /* Set up the entry state */
> -    spapr_cpu_set_entry_state(first_ppc_cpu, SPAPR_ENTRY_POINT, fdt_addr);
> -    first_ppc_cpu->env.gpr[5] = 0;
> +    if (spapr->bios_enabled) {
> +        /* Load the fdt */
> +        rc = fdt_pack(spapr->fdt_blob);
> +        /* Should only fail if we've built a corrupted tree */
> +        assert(rc == 0);
> +
> +        spapr->fdt_size = fdt_totalsize(spapr->fdt_blob);
> +        spapr->fdt_initial_size = spapr->fdt_size;
> +        qemu_fdt_dumpdtb(spapr->fdt_blob, spapr->fdt_size);

I think we should still have a dumpdtb call on the !bios path.

> +        cpu_physical_memory_write(fdt_addr, spapr->fdt_blob, 
> spapr->fdt_size);
> +    } else {
> +        char *stdout_path = spapr_vio_stdout_path(spapr->vio_bus);
> +        int offset = fdt_path_offset(fdt, "/chosen");
> +
> +        /*
> +         * SLOF-less setup requires an open instance of stdout for early
> +         * kernel printk. By now all phandles are settled so we can open
> +         * the default serial console.
> +         * We skip writing FDT as nothing expects it; OF client interface is
> +         * going to be used for reading the device tree.
> +         */
> +        if (stdout_path) {
> +            _FDT(fdt_setprop_cell(fdt, offset, "stdout",
> +                                  spapr_of_client_open(spapr, stdout_path)));
> +        }
> +    }
>  
>      spapr->cas_reboot = false;
>  }
> @@ -2897,12 +3061,12 @@ static void spapr_machine_init(MachineState *machine)
>          uint64_t lowaddr = 0;
>  
>          spapr->kernel_size = load_elf(kernel_filename, NULL,
> -                                      translate_kernel_address, NULL,
> +                                      translate_kernel_address, spapr,
>                                        NULL, &lowaddr, NULL, 1,
>                                        PPC_ELF_MACHINE, 0, 0);
>          if (spapr->kernel_size == ELF_LOAD_WRONG_ENDIAN) {
>              spapr->kernel_size = load_elf(kernel_filename, NULL,
> -                                          translate_kernel_address, NULL, 
> NULL,
> +                                          translate_kernel_address, spapr, 
> NULL,
>                                            &lowaddr, NULL, 0, PPC_ELF_MACHINE,
>                                            0, 0);
>              spapr->kernel_le = spapr->kernel_size > 0;
> @@ -2918,7 +3082,7 @@ static void spapr_machine_init(MachineState *machine)
>              /* Try to locate the initrd in the gap between the kernel
>               * and the firmware. Add a bit of space just in case
>               */
> -            spapr->initrd_base = (KERNEL_LOAD_ADDR + spapr->kernel_size
> +            spapr->initrd_base = (spapr->kernel_addr + spapr->kernel_size
>                                    + 0x1ffff) & ~0xffff;
>              spapr->initrd_size = load_image_targphys(initrd_filename,
>                                                       spapr->initrd_base,
> @@ -2932,20 +3096,22 @@ static void spapr_machine_init(MachineState *machine)
>          }
>      }
>  
> -    if (bios_name == NULL) {
> -        bios_name = FW_FILE_NAME;
> +    if (spapr->bios_enabled) {
> +        if (bios_name == NULL) {
> +            bios_name = FW_FILE_NAME;
> +        }
> +        filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> +        if (!filename) {
> +            error_report("Could not find LPAR firmware '%s'", bios_name);
> +            exit(1);
> +        }
> +        fw_size = load_image_targphys(filename, 0, FW_MAX_SIZE);
> +        if (fw_size <= 0) {
> +            error_report("Could not load LPAR firmware '%s'", filename);
> +            exit(1);
> +        }
> +        g_free(filename);
>      }
> -    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> -    if (!filename) {
> -        error_report("Could not find LPAR firmware '%s'", bios_name);
> -        exit(1);
> -    }
> -    fw_size = load_image_targphys(filename, 0, FW_MAX_SIZE);
> -    if (fw_size <= 0) {
> -        error_report("Could not load LPAR firmware '%s'", filename);
> -        exit(1);
> -    }
> -    g_free(filename);
>  
>      /* FIXME: Should register things through the MachineState's qdev
>       * interface, this is a legacy from the sPAPREnvironment structure
> @@ -3162,6 +3328,32 @@ static void spapr_set_vsmt(Object *obj, Visitor *v, 
> const char *name,
>      visit_type_uint32(v, name, (uint32_t *)opaque, errp);
>  }
>  
> +static void spapr_get_kernel_addr(Object *obj, Visitor *v, const char *name,
> +                                  void *opaque, Error **errp)
> +{
> +    visit_type_uint64(v, name, (uint64_t *)opaque, errp);
> +}
> +
> +static void spapr_set_kernel_addr(Object *obj, Visitor *v, const char *name,
> +                                  void *opaque, Error **errp)
> +{
> +    visit_type_uint64(v, name, (uint64_t *)opaque, errp);
> +}
> +
> +static bool spapr_get_bios_enabled(Object *obj, Error **errp)
> +{
> +    SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    return spapr->bios_enabled;
> +}
> +
> +static void spapr_set_bios_enabled(Object *obj, bool value, Error **errp)
> +{
> +    SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    spapr->bios_enabled = value;
> +}
> +
>  static char *spapr_get_ic_mode(Object *obj, Error **errp)
>  {
>      SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> @@ -3267,6 +3459,20 @@ static void spapr_instance_init(Object *obj)
>      object_property_add_bool(obj, "vfio-no-msix-emulation",
>                               spapr_get_msix_emulation, NULL, NULL);
>  
> +    object_property_add(obj, "kernel-addr", "uint64", spapr_get_kernel_addr,
> +                        spapr_set_kernel_addr, NULL, &spapr->kernel_addr,
> +                        &error_abort);
> +    object_property_set_description(obj, "kernel-addr",
> +                                    stringify(KERNEL_LOAD_ADDR)
> +                                    " for -kernel is the default",
> +                                    NULL);
> +    spapr->kernel_addr = KERNEL_LOAD_ADDR;
> +    object_property_add_bool(obj, "bios", spapr_get_bios_enabled,
> +                            spapr_set_bios_enabled, NULL);
> +    object_property_set_description(obj, "bios", "Conrols whether to load 
> bios",
> +                                    NULL);
> +    spapr->bios_enabled = true;
> +
>      /* The machine class defines the default interrupt controller mode */
>      spapr->irq = smc->irq;
>      object_property_add_str(obj, "ic-mode", spapr_get_ic_mode,
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index f1799b1b707d..f2d8823d2c3a 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1660,15 +1660,11 @@ static bool spapr_hotplugged_dev_before_cas(void)
>      return false;
>  }
>  
> -static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
> -                                                  SpaprMachineState *spapr,
> -                                                  target_ulong opcode,
> -                                                  target_ulong *args)
> +target_ulong do_client_architecture_support(PowerPCCPU *cpu,
> +                                            SpaprMachineState *spapr,
> +                                            target_ulong addr,
> +                                            target_ulong fdt_bufsize)
>  {
> -    /* Working address in data buffer */
> -    target_ulong addr = ppc64_phys_to_real(args[0]);
> -    target_ulong fdt_buf = args[1];
> -    target_ulong fdt_bufsize = args[2];
>      target_ulong ov_table;
>      uint32_t cas_pvr;
>      SpaprOptionVector *ov1_guest, *ov5_guest, *ov5_cas_old;
> @@ -1816,7 +1812,6 @@ static target_ulong 
> h_client_architecture_support(PowerPCCPU *cpu,
>  
>      if (!spapr->cas_reboot) {
>          void *fdt;
> -        SpaprDeviceTreeUpdateHeader hdr = { .version_id = 1 };
>  
>          /* If spapr_machine_reset() did not set up a HPT but one is necessary
>           * (because the guest isn't going to use radix) then set it up here. 
> */
> @@ -1825,21 +1820,7 @@ static target_ulong 
> h_client_architecture_support(PowerPCCPU *cpu,
>              spapr_setup_hpt_and_vrma(spapr);
>          }
>  
> -        if (fdt_bufsize < sizeof(hdr)) {
> -            error_report("SLOF provided insufficient CAS buffer "
> -                         TARGET_FMT_lu " (min: %zu)", fdt_bufsize, 
> sizeof(hdr));
> -            exit(EXIT_FAILURE);
> -        }
> -
> -        fdt_bufsize -= sizeof(hdr);
> -
> -        fdt = spapr_build_fdt(spapr, false, fdt_bufsize);
> -        _FDT((fdt_pack(fdt)));
> -
> -        cpu_physical_memory_write(fdt_buf, &hdr, sizeof(hdr));
> -        cpu_physical_memory_write(fdt_buf + sizeof(hdr), fdt,
> -                                  fdt_totalsize(fdt));
> -        trace_spapr_cas_continue(fdt_totalsize(fdt) + sizeof(hdr));
> +        fdt = spapr_build_fdt(spapr, !spapr->bios_enabled, fdt_bufsize);
>  
>          g_free(spapr->fdt_blob);
>          spapr->fdt_size = fdt_totalsize(fdt);
> @@ -1854,6 +1835,41 @@ static target_ulong 
> h_client_architecture_support(PowerPCCPU *cpu,
>      return H_SUCCESS;
>  }
>  
> +static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
> +                                                  SpaprMachineState *spapr,
> +                                                  target_ulong opcode,
> +                                                  target_ulong *args)
> +{
> +    /* Working address in data buffer */
> +    target_ulong addr = ppc64_phys_to_real(args[0]);
> +    target_ulong fdt_buf = args[1];
> +    target_ulong fdt_bufsize = args[2];
> +    target_ulong ret;
> +    SpaprDeviceTreeUpdateHeader hdr = { .version_id = 1 };
> +
> +    if (fdt_bufsize < sizeof(hdr)) {
> +        error_report("SLOF provided insufficient CAS buffer "
> +                     TARGET_FMT_lu " (min: %zu)", fdt_bufsize, sizeof(hdr));
> +        exit(EXIT_FAILURE);
> +    }
> +
> +    fdt_bufsize -= sizeof(hdr);
> +
> +    ret = do_client_architecture_support(cpu, spapr, addr, fdt_bufsize);
> +    if (ret == H_SUCCESS) {
> +        _FDT((fdt_pack(spapr->fdt_blob)));
> +        spapr->fdt_size = fdt_totalsize(spapr->fdt_blob);
> +        spapr->fdt_initial_size = spapr->fdt_size;
> +
> +        cpu_physical_memory_write(fdt_buf, &hdr, sizeof(hdr));
> +        cpu_physical_memory_write(fdt_buf + sizeof(hdr), spapr->fdt_blob,
> +                                  spapr->fdt_size);
> +        trace_spapr_cas_continue(spapr->fdt_size + sizeof(hdr));
> +    }
> +
> +    return ret;
> +}
> +
>  static target_ulong h_home_node_associativity(PowerPCCPU *cpu,
>                                                SpaprMachineState *spapr,
>                                                target_ulong opcode,
> @@ -1998,6 +2014,14 @@ static target_ulong h_update_dt(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>      return H_SUCCESS;
>  }
>  
> +static target_ulong h_client(PowerPCCPU *cpu, SpaprMachineState *spapr,
> +                             target_ulong opcode, target_ulong *args)

As I said in an earlier revision, please explan these names from just
"client", for readability by people who aren't already thinking about
open firmware.

> +{
> +    target_ulong client_args = ppc64_phys_to_real(args[0]);
> +
> +    return spapr_h_client(spapr, client_args);
> +}
> +
>  static spapr_hcall_fn papr_hypercall_table[(MAX_HCALL_OPCODE / 4) + 1];
>  static spapr_hcall_fn kvmppc_hypercall_table[KVMPPC_HCALL_MAX - 
> KVMPPC_HCALL_BASE + 1];
>  static spapr_hcall_fn svm_hypercall_table[(SVM_HCALL_MAX - SVM_HCALL_BASE) / 
> 4 + 1];
> @@ -2121,6 +2145,8 @@ static void hypercall_register_types(void)
>  
>      spapr_register_hypercall(KVMPPC_H_UPDATE_DT, h_update_dt);
>  
> +    spapr_register_hypercall(KVMPPC_H_CLIENT, h_client);
> +
>      /* Virtual Processor Home Node */
>      spapr_register_hypercall(H_HOME_NODE_ASSOCIATIVITY,
>                               h_home_node_associativity);
> diff --git a/hw/ppc/spapr_of_client.c b/hw/ppc/spapr_of_client.c
> new file mode 100644
> index 000000000000..24d854b76e51
> --- /dev/null
> +++ b/hw/ppc/spapr_of_client.c

I'd suggest expanding this file to cover as much as you can of the
virtual OF stuff, not just the client interface.

> @@ -0,0 +1,633 @@
> +#include "qemu/osdep.h"
> +#include "qemu-common.h"
> +#include "qapi/error.h"
> +#include "exec/memory.h"
> +#include "hw/ppc/spapr.h"
> +#include "hw/ppc/spapr_vio.h"
> +#include "chardev/char.h"
> +#include "qom/qom-qobject.h"
> +#include "trace.h"
> +
> +typedef struct {
> +    DeviceState *dev;
> +    Chardev *cdev;
> +    uint32_t phandle;
> +} SpaprOfInstance;
> +
> +/*
> + * OF 1275 "nextprop" description suggests is it 32 bytes max but
> + * LoPAPR defines "ibm,query-interrupt-source-number" which is 33 chars long.
> + */
> +#define OF_PROPNAME_LEN_MAX 64
> +
> +/* Defined as Big Endian */
> +struct prom_args {
> +    uint32_t service;
> +    uint32_t nargs;
> +    uint32_t nret;
> +    uint32_t args[10];
> +};
> +
> +static void readstr(hwaddr pa, char *buf, int size)
> +{
> +    cpu_physical_memory_read(pa, buf, size - 1);
> +    buf[size - 1] = 0;
> +}

I'd still like to see this return some kind of error if it had to
truncate what was passed by the client.

> +
> +static bool _cmpservice(const char *s, size_t len,

Don't use leading _ please - in userland those are reserved for the
system libraries.

> +                        unsigned nargs, unsigned nret,
> +                        const char *s1, size_t len1,
> +                        unsigned nargscheck, unsigned nretcheck)
> +{
> +    if (strcmp(s, s1)) {
> +        return false;
> +    }
> +    if (nargscheck == 0 && nretcheck == 0) {
> +        return true;
> +    }
> +    if (nargs != nargscheck || nret != nretcheck) {
> +        trace_spapr_of_client_error_param(s, nargscheck, nretcheck, nargs,
> +                                          nret);
> +        return false;
> +    }
> +
> +    return true;
> +}
> +
> +static uint32_t of_client_finddevice(const void *fdt, uint32_t nodeaddr)
> +{
> +    char node[256];

Is 256 enough?  OF paths can get pretty long...

> +    int ret;
> +
> +    readstr(nodeaddr, node, sizeof(node));
> +    ret = fdt_path_offset(fdt, node);
> +    if (ret >= 0) {
> +        ret = fdt_get_phandle(fdt, ret);
> +    }
> +
> +    return (uint32_t) ret;
> +}
> +
> +static uint32_t of_client_getprop(const void *fdt, uint32_t nodeph,
> +                                  uint32_t pname, uint32_t valaddr,
> +                                  uint32_t vallen)
> +{
> +    char propname[OF_PROPNAME_LEN_MAX + 1];
> +    uint32_t ret = 0;
> +    int proplen = 0;
> +    const void *prop;
> +
> +    readstr(pname, propname, sizeof(propname));
> +    prop = fdt_getprop_namelen(fdt, fdt_node_offset_by_phandle(fdt, nodeph),
> +                               propname, strlen(propname), &proplen);

Again, you don't need _namelen.

> +    if (prop) {
> +        int cb = MIN(proplen, vallen);
> +
> +        cpu_physical_memory_write(valaddr, prop, cb);
> +        ret = cb;

If I'm reading 1275 correctly, the return value should be the
untruncated length of the property.

> +    } else {
> +        ret = -1;
> +    }
> +    trace_spapr_of_client_getprop(nodeph, propname, ret);
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_getproplen(const void *fdt, uint32_t nodeph,
> +                                     uint32_t pname)
> +{
> +    char propname[OF_PROPNAME_LEN_MAX + 1];
> +    uint32_t ret = 0;
> +    int proplen = 0;
> +    const void *prop;
> +
> +    readstr(pname, propname, sizeof(propname));
> +
> +    prop = fdt_getprop_namelen(fdt, fdt_node_offset_by_phandle(fdt, nodeph),
> +                               propname, strlen(propname), &proplen);

No _namelen.

> +    if (prop) {
> +        ret = proplen;
> +    } else {
> +        ret = -1;
> +    }
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_setprop(SpaprMachineState *spapr,
> +                                  uint32_t nodeph, uint32_t pname,
> +                                  uint32_t valaddr, uint32_t vallen)
> +{
> +    char propname[OF_PROPNAME_LEN_MAX + 1];
> +    uint32_t ret = -1;
> +    int offset;

A comment noting that you're only allowing a very restricted set of
setprops would be good.

> +    readstr(pname, propname, sizeof(propname));
> +    if (vallen == sizeof(uint32_t)) {
> +        uint32_t val32 = ldl_be_phys(first_cpu->as, valaddr);
> +
> +        if ((strcmp(propname, "linux,rtas-base") == 0) ||
> +            (strcmp(propname, "linux,rtas-entry") == 0)) {
> +            spapr->rtas_base = val32;
> +        } else if (strcmp(propname, "linux,initrd-start") == 0) {
> +            spapr->initrd_base = val32;
> +        } else if (strcmp(propname, "linux,initrd-end") == 0) {
> +            spapr->initrd_size = val32 - spapr->initrd_base;
> +        } else {
> +            goto trace_exit;
> +        }
> +    } else if (vallen == sizeof(uint64_t)) {
> +        uint64_t val64 = ldq_be_phys(first_cpu->as, valaddr);
> +
> +        if (strcmp(propname, "linux,initrd-start") == 0) {
> +            spapr->initrd_base = val64;
> +        } else if (strcmp(propname, "linux,initrd-end") == 0) {
> +            spapr->initrd_size = val64 - spapr->initrd_base;
> +        } else {
> +            goto trace_exit;
> +        }
> +    } else {
> +        goto trace_exit;
> +    }
> +
> +    offset = fdt_node_offset_by_phandle(spapr->fdt_blob, nodeph);
> +    if (offset >= 0) {
> +        uint8_t data[vallen];
> +
> +        cpu_physical_memory_read(valaddr, data, vallen);
> +        if (!fdt_setprop(spapr->fdt_blob, offset, propname, data, vallen)) {
> +            ret = vallen;
> +        }
> +    }
> +
> +trace_exit:
> +    trace_spapr_of_client_setprop(nodeph, propname, ret);
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_nextprop(const void *fdt, uint32_t phandle,
> +                                   uint32_t prevaddr, uint32_t nameaddr)
> +{
> +    int offset = fdt_node_offset_by_phandle(fdt, phandle);
> +    char prev[OF_PROPNAME_LEN_MAX + 1];
> +    const char *tmp;
> +
> +    readstr(prevaddr, prev, sizeof(prev));
> +    for (offset = fdt_first_property_offset(fdt, offset);
> +         offset >= 0;
> +         offset = fdt_next_property_offset(fdt, offset)) {
> +
> +        if (!fdt_getprop_by_offset(fdt, offset, &tmp, NULL)) {
> +            return 0;
> +        }
> +        if (prev[0] == '\0' || strcmp(prev, tmp) == 0) {
> +            if (prev[0] != '\0') {
> +                offset = fdt_next_property_offset(fdt, offset);
> +                if (offset < 0) {
> +                    return 0;
> +                }
> +            }
> +            if (!fdt_getprop_by_offset(fdt, offset, &tmp, NULL)) {
> +                return 0;
> +            }
> +            cpu_physical_memory_write(nameaddr, tmp, strlen(tmp) + 1);
> +            return 1;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +static uint32_t of_client_peer(const void *fdt, uint32_t phandle)
> +{
> +    int ret;
> +
> +    if (phandle == 0) {
> +        ret = fdt_path_offset(fdt, "/");
> +    } else {
> +        ret = fdt_next_subnode(fdt, fdt_node_offset_by_phandle(fdt, 
> phandle));
> +    }
> +
> +    if (ret < 0) {
> +        ret = 0;
> +    } else {
> +        ret = fdt_get_phandle(fdt, ret);
> +    }
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_child(const void *fdt, uint32_t phandle)
> +{
> +    int ret = fdt_first_subnode(fdt, fdt_node_offset_by_phandle(fdt, 
> phandle));
> +
> +    if (ret < 0) {
> +        ret = 0;
> +    } else {
> +        ret = fdt_get_phandle(fdt, ret);
> +    }
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_parent(const void *fdt, uint32_t phandle)
> +{
> +    int ret = fdt_parent_offset(fdt, fdt_node_offset_by_phandle(fdt, 
> phandle));
> +
> +    if (ret < 0) {
> +        ret = 0;
> +    } else {
> +        ret = fdt_get_phandle(fdt, ret);
> +    }
> +
> +    return ret;
> +}
> +
> +static DeviceState *of_client_find_qom_dev(BusState *bus, const char *path)
> +{
> +    BusChild *kid;
> +
> +    QTAILQ_FOREACH(kid, &bus->children, sibling) {
> +        const char *p = qdev_get_fw_dev_path(kid->child);
> +        BusState *child;
> +
> +        if (p && strcmp(path, p) == 0) {
> +            return kid->child;
> +        }
> +        QLIST_FOREACH(child, &kid->child->child_bus, sibling) {
> +            DeviceState *d = of_client_find_qom_dev(child, path);
> +
> +            if (d) {
> +                return d;
> +            }
> +        }
> +    }
> +    return NULL;
> +}
> +
> +uint32_t spapr_of_client_open(SpaprMachineState *spapr, const char *path)
> +{
> +    int offset;
> +    uint32_t ret = 0;
> +    SpaprOfInstance *inst;
> +
> +    if (spapr->of_instance_last == 0xFFFFFFFF) {
> +        /* We do not recycle ihandles yet */
> +        goto trace_exit;
> +    }
> +    offset = fdt_path_offset(spapr->fdt_blob, path);
> +    if (offset < 0) {
> +        trace_spapr_of_client_error_unknown_path(path);
> +        goto trace_exit;
> +    }
> +
> +    inst = g_new(SpaprOfInstance, 1);
> +    inst->phandle = fdt_get_phandle(spapr->fdt_blob, offset);
> +    g_assert(inst->phandle);
> +    ++spapr->of_instance_last;
> +    inst->dev = of_client_find_qom_dev(sysbus_get_default(), path);
> +    g_hash_table_insert(spapr->of_instances,
> +                        GINT_TO_POINTER(spapr->of_instance_last),
> +                        inst);
> +    ret = spapr->of_instance_last;
> +
> +    if (inst->dev) {
> +        const char *cdevstr = object_property_get_str(OBJECT(inst->dev),
> +                                                      "chardev", NULL);
> +
> +        if (cdevstr) {
> +            inst->cdev = qemu_chr_find(cdevstr);
> +        }
> +    }
> +
> +trace_exit:
> +    trace_spapr_of_client_open(path, inst ? inst->phandle : 0, ret);
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_open(SpaprMachineState *spapr, uint32_t pathaddr)
> +{
> +    char path[256];
> +
> +    readstr(pathaddr, path, sizeof(path));
> +
> +    return spapr_of_client_open(spapr, path);
> +}
> +
> +static void of_client_close(SpaprMachineState *spapr, uint32_t ihandle)
> +{
> +    if (!g_hash_table_remove(spapr->of_instances, GINT_TO_POINTER(ihandle))) 
> {
> +        trace_spapr_of_client_error_unknown_ihandle_close(ihandle);
> +    }
> +}
> +
> +static uint32_t of_client_instance_to_package(SpaprMachineState *spapr,
> +                                              uint32_t ihandle)
> +{
> +    gpointer instp = g_hash_table_lookup(spapr->of_instances,
> +                                        GINT_TO_POINTER(ihandle));
> +
> +    if (!instp) {
> +        return -1;
> +    }
> +
> +    return ((SpaprOfInstance *)instp)->phandle;
> +}
> +
> +static uint32_t of_client_package_to_path(const void *fdt, uint32_t phandle,
> +                                          uint32_t buf, uint32_t len)
> +{
> +    char tmp[256];
> +
> +    if (0 == fdt_get_path(fdt, fdt_node_offset_by_phandle(fdt, phandle), tmp,
> +                          sizeof(tmp))) {
> +        tmp[sizeof(tmp) - 1] = 0;
> +        cpu_physical_memory_write(buf, tmp, MIN(len, strlen(tmp)));
> +    }
> +    return len;
> +}
> +
> +static uint32_t of_client_instance_to_path(SpaprMachineState *spapr,
> +                                           uint32_t ihandle, uint32_t buf,
> +                                           uint32_t len)
> +{
> +    uint32_t phandle = of_client_instance_to_package(spapr, ihandle);
> +
> +    if (phandle != -1) {
> +        return of_client_package_to_path(spapr->fdt_blob, phandle, buf, len);
> +    }
> +
> +    return 0;
> +}
> +
> +static uint32_t of_client_write(SpaprMachineState *spapr, uint32_t ihandle,
> +                                uint32_t buf, uint32_t len)
> +{
> +    char tmp[256];
> +    int toread, toprint, cb = MIN(len, 1024);
> +    SpaprOfInstance *inst = (SpaprOfInstance *)
> +        g_hash_table_lookup(spapr->of_instances, GINT_TO_POINTER(ihandle));
> +
> +    while (cb > 0) {
> +        toread = MIN(cb + 1, sizeof(tmp));
> +        readstr(buf, tmp, toread);
> +        toprint = strlen(tmp);
> +        if (inst && inst->cdev) {
> +            toprint = qemu_chr_write(inst->cdev, (uint8_t *) tmp, toprint,
> +                                     true);
> +        } else {
> +            /* We normally open stdout so this is fallback */
> +            printf("DBG[%d]%s", ihandle, tmp);
> +        }
> +        buf += toprint;
> +        cb -= toprint;
> +    }
> +
> +    return len;
> +}
> +
> +static bool of_client_claim_avail(GArray *claimed, uint64_t virt, uint64_t 
> size)
> +{
> +    int i;
> +    SpaprOfClaimed *c;
> +
> +    for (i = 0; i < claimed->len; ++i) {
> +        c = &g_array_index(claimed, SpaprOfClaimed, i);
> +        if ((c->start <= virt && virt < c->start + c->size) ||
> +            (virt <= c->start && c->start < virt + size)) {
> +            return false;
> +        }
> +    }
> +
> +    return true;
> +}
> +
> +static void of_client_claim_add(GArray *claimed, uint64_t virt, uint64_t 
> size)
> +{
> +    SpaprOfClaimed newclaim;
> +
> +    newclaim.start = virt;
> +    newclaim.size = size;
> +    g_array_append_val(claimed, newclaim);
> +}
> +
> +/*
> + * "claim" claims memory at @virt if @align==0; otherwise it allocates
> + * memory at the requested alignment.
> + */
> +uint64_t spapr_do_of_client_claim(SpaprMachineState *spapr, uint64_t virt,
> +                                  uint64_t size, uint64_t align)
> +{
> +    uint32_t ret;
> +
> +    if (align == 0) {
> +        if (!of_client_claim_avail(spapr->claimed, virt, size)) {
> +            return -1;
> +        }
> +        ret = virt;
> +    } else {
> +        align = pow2ceil(align);

Should this be a pow2ceil, or should it just return an error if align
is not a power of 2.  Note that aligning something to 4 bytes will
(probably) make it *not* aligned to 3 bytes.

> +        spapr->claimed_base = (spapr->claimed_base + align - 1) & ~(align - 
> 1);
> +        while (1) {
> +            if (spapr->claimed_base >= spapr->rma_size) {
> +                perror("Out of memory");

error_report() or qemu_log() or something and a message with some more
specificity, please.

> +                return -1;
> +            }
> +            if (of_client_claim_avail(spapr->claimed, spapr->claimed_base,
> +                                      size)) {
> +                break;
> +            }
> +            spapr->claimed_base += size;
> +        }
> +        ret = spapr->claimed_base;
> +    }
> +
> +    spapr->claimed_base = MAX(spapr->claimed_base, ret + size);
> +    of_client_claim_add(spapr->claimed, virt, size);
> +    trace_spapr_of_client_claim(virt, size, align, ret);
> +
> +    return ret;
> +}
> +
> +static uint32_t of_client_claim(SpaprMachineState *spapr, uint32_t virt,
> +                                uint32_t size, uint32_t align)
> +{
> +    if (align) {
> +        return -1;
> +    }
> +    if (!of_client_claim_avail(spapr->claimed, virt, size)) {
> +        return -1;
> +    }
> +
> +    spapr->claimed_base = MAX(spapr->claimed_base, virt + size);
> +    of_client_claim_add(spapr->claimed, virt, size);
> +    trace_spapr_of_client_claim(virt, size, align, virt);

Huh.  So do_of_client_claim() is never used from of_client_claim(),
only from "internal" claimers.  It definitely needs a different name.

> +    return virt;
> +}
> +
> +static uint32_t of_client_call_method(SpaprMachineState *spapr,
> +                                      uint32_t methodaddr, uint32_t ihandle,
> +                                      uint32_t param, uint32_t *ret2)
> +{
> +    uint32_t ret = -1;
> +    char path[256] = "", method[256] = "";
> +    uint32_t phandle = of_client_instance_to_package(spapr, ihandle);
> +    int offset;
> +
> +    if (!ihandle) {
> +        goto trace_exit;
> +    }
> +
> +    readstr(methodaddr, method, sizeof(method));
> +    phandle = of_client_instance_to_package(spapr, ihandle);
> +    if (!phandle) {
> +        goto trace_exit;
> +    }
> +
> +    offset = fdt_node_offset_by_phandle(spapr->fdt_blob, phandle);
> +    if (offset < 0) {
> +        goto trace_exit;
> +    }
> +
> +    if (fdt_get_path(spapr->fdt_blob, offset, path, sizeof(path))) {
> +        goto trace_exit;
> +    }
> +
> +    if (strcmp(path, "/") == 0) {
> +        if (strcmp(method, "ibm,client-architecture-support") == 0) {
> +
> +#define FDT_MAX_SIZE            0x100000
> +            ret = do_client_architecture_support(POWERPC_CPU(first_cpu), 
> spapr,
> +                                                 param, FDT_MAX_SIZE);
> +            *ret2 = 0;
> +        }
> +    } else if (strcmp(path, "/rtas") == 0) {
> +        if (strcmp(method, "instantiate-rtas") == 0) {
> +            spapr_instantiate_rtas(spapr, param);
> +            ret = 0;
> +            *ret2 = param; /* rtasbase */
> +        }
> +    } else {
> +        trace_spapr_of_client_error_unknown_method(method);
> +    }
> +
> +trace_exit:
> +    trace_spapr_of_client_method(ihandle, method, param, phandle, path, ret);
> +
> +    return ret;
> +}
> +
> +static void of_client_quiesce(SpaprMachineState *spapr)
> +{
> +    int rc = fdt_pack(spapr->fdt_blob);
> +    /* Should only fail if we've built a corrupted tree */
> +    assert(rc == 0);
> +
> +    spapr->fdt_size = fdt_totalsize(spapr->fdt_blob);
> +    spapr->fdt_initial_size = spapr->fdt_size;
> +}
> +
> +int spapr_h_client(SpaprMachineState *spapr, target_ulong of_client_args)
> +{
> +    struct prom_args args = { 0 };
> +    char service[64];
> +    unsigned nargs, nret;
> +    int i, servicelen;
> +
> +    cpu_physical_memory_read(of_client_args, &args, sizeof(args));
> +    nargs = be32_to_cpu(args.nargs);
> +    nret = be32_to_cpu(args.nret);
> +    readstr(be32_to_cpu(args.service), service, sizeof(service));
> +    servicelen = strlen(service);
> +
> +#define cmpservice(s, a, r) \
> +    _cmpservice(service, servicelen, nargs, nret, (s), sizeof(s), (a), (r))
> +
> +    if (cmpservice("finddevice", 1, 1)) {
> +        args.args[nargs] = of_client_finddevice(spapr->fdt_blob,
> +                                                be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("getprop", 4, 1)) {
> +        args.args[nargs] = of_client_getprop(spapr->fdt_blob,
> +                                             be32_to_cpu(args.args[0]),
> +                                             be32_to_cpu(args.args[1]),
> +                                             be32_to_cpu(args.args[2]),
> +                                             be32_to_cpu(args.args[3]));
> +    } else if (cmpservice("getproplen", 2, 1)) {
> +        args.args[nargs] = of_client_getproplen(spapr->fdt_blob,
> +                                                be32_to_cpu(args.args[0]),
> +                                                be32_to_cpu(args.args[1]));
> +    } else if (cmpservice("setprop", 4, 1)) {
> +        args.args[nargs] = of_client_setprop(spapr,
> +                                             be32_to_cpu(args.args[0]),
> +                                             be32_to_cpu(args.args[1]),
> +                                             be32_to_cpu(args.args[2]),
> +                                             be32_to_cpu(args.args[3]));
> +    } else if (cmpservice("nextprop", 3, 1)) {
> +        args.args[nargs] = of_client_nextprop(spapr->fdt_blob,
> +                                              be32_to_cpu(args.args[0]),
> +                                              be32_to_cpu(args.args[1]),
> +                                              be32_to_cpu(args.args[2]));
> +    } else if (cmpservice("peer", 1, 1)) {
> +        args.args[nargs] = of_client_peer(spapr->fdt_blob,
> +                                          be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("child", 1, 1)) {
> +        args.args[nargs] = of_client_child(spapr->fdt_blob,
> +                                           be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("parent", 1, 1)) {
> +        args.args[nargs] = of_client_parent(spapr->fdt_blob,
> +                                            be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("open", 1, 1)) {
> +        args.args[nargs] = of_client_open(spapr, be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("close", 1, 0)) {
> +        of_client_close(spapr, be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("instance-to-package", 1, 1)) {
> +        args.args[nargs] =
> +            of_client_instance_to_package(spapr,
> +                                          be32_to_cpu(args.args[0]));
> +    } else if (cmpservice("package-to-path", 3, 1)) {
> +        args.args[nargs] = of_client_package_to_path(spapr->fdt_blob,
> +                                                     
> be32_to_cpu(args.args[0]),
> +                                                     
> be32_to_cpu(args.args[1]),
> +                                                     
> be32_to_cpu(args.args[2]));
> +    } else if (cmpservice("instance-to-path", 3, 1)) {
> +        args.args[nargs] =
> +            of_client_instance_to_path(spapr,
> +                                       be32_to_cpu(args.args[0]),
> +                                       be32_to_cpu(args.args[1]),
> +                                       be32_to_cpu(args.args[2]));
> +    } else if (cmpservice("write", 3, 1)) {
> +        args.args[nargs] = of_client_write(spapr,
> +                                           be32_to_cpu(args.args[0]),
> +                                           be32_to_cpu(args.args[1]),
> +                                           be32_to_cpu(args.args[2]));
> +    } else if (cmpservice("claim", 3, 1)) {
> +        args.args[nargs] = of_client_claim(spapr,
> +                                           be32_to_cpu(args.args[0]),
> +                                           be32_to_cpu(args.args[1]),
> +                                           be32_to_cpu(args.args[2]));
> +    } else if (cmpservice("call-method", 3, 2)) {
> +        args.args[nargs] = of_client_call_method(spapr,
> +                                                 be32_to_cpu(args.args[0]),
> +                                                 be32_to_cpu(args.args[1]),
> +                                                 be32_to_cpu(args.args[2]),
> +                                                 &args.args[nargs + 1]);
> +    } else if (cmpservice("quiesce", 0, 0)) {
> +        of_client_quiesce(spapr);
> +    } else if (cmpservice("exit", 0, 0)) {
> +        error_report("Stopped as the VM requested \"exit\"");
> +        vm_stop(RUN_STATE_PAUSED);
> +    } else {
> +        trace_spapr_of_client_error_unknown_service(service, nargs, nret);
> +        args.args[nargs] = -1;

You've never bounds checked nargs at this point.

> +    }
> +
> +    for (i = 0; i < nret; ++i) {

And likewise you might not have bounds checked nret.

> +        args.args[nargs + i] = be32_to_cpu(args.args[nargs + i]);
> +    }
> +    cpu_physical_memory_write(of_client_args, &args, sizeof(args));
> +
> +    return H_SUCCESS;
> +}
> diff --git a/hw/ppc/trace-events b/hw/ppc/trace-events
> index 9ea620f23c85..e2d1e58d07c3 100644
> --- a/hw/ppc/trace-events
> +++ b/hw/ppc/trace-events
> @@ -21,6 +21,18 @@ spapr_update_dt(unsigned cb) "New blob %u bytes"
>  spapr_update_dt_failed_size(unsigned cbold, unsigned cbnew, unsigned magic) 
> "Old blob %u bytes, new blob %u bytes, magic 0x%x"
>  spapr_update_dt_failed_check(unsigned cbold, unsigned cbnew, unsigned magic) 
> "Old blob %u bytes, new blob %u bytes, magic 0x%x"
>  
> +# spapr_client.c
> +spapr_of_client_error_param(const char *method, int nargscheck, int 
> nretcheck, int nargs, int nret) "%s takes/returns %d/%d, not %d/%d"
> +spapr_of_client_error_unknown_service(const char *service, int nargs, int 
> nret) "%s args=%d rets=%d"
> +spapr_of_client_error_unknown_method(const char *method) "%s"
> +spapr_of_client_error_unknown_ihandle_close(uint32_t ihandle) "0x%x"
> +spapr_of_client_error_unknown_path(const char *path) "%s"
> +spapr_of_client_claim(uint32_t virt, uint32_t size, uint32_t align, uint32_t 
> ret) "virt=0x%x size=0x%x align=0x%x => 0x%x"
> +spapr_of_client_method(uint32_t ihandle, const char *method, uint32_t param, 
> uint32_t phandle, const char *path, uint32_t ret) "0x%x \"%s\" param=0x%x 
> ph=0x%x \"%s\" => 0x%x"
> +spapr_of_client_getprop(uint32_t ph, const char *prop, uint32_t ret) 
> "phandle=0x%x \"%s\" => 0x%x"
> +spapr_of_client_setprop(uint32_t ph, const char *prop, uint32_t ret) 
> "phandle=0x%x \"%s\" => 0x%x"
> +spapr_of_client_open(const char *path, uint32_t phandle, uint32_t ihandle) 
> "%s 0x%x => 0x%x"
> +
>  # spapr_hcall_tpm.c
>  spapr_h_tpm_comm(const char *device_path, uint64_t operation) 
> "tpm_device_path=%s operation=0x%"PRIu64
>  spapr_tpm_execute(uint64_t data_in, uint64_t data_in_sz, uint64_t data_out, 
> uint64_t data_out_sz) "data_in=0x%"PRIx64", data_in_sz=%"PRIu64", 
> data_out=0x%"PRIx64", data_out_sz=%"PRIu64

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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