Re: [PATCH] hppa: allow max ram size upto 4Gb

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/2/20 6:08 PM, Igor Mammedov wrote:
> Previous patch drops silent ram_size fixup and makes
> QEMU error out with:
> 
>   "RAM size more than 3840m is not supported"
> 
> when user specified -m X more than supported value.
> 
> User shouldn't be bothered with starting QEMU with valid CLI,
> so for the sake of user convenience to allow using -m 4G vs -m 3840M.
> 
> Requested-by: Helge Deller <deller@gmx.de>
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> I dislike it but if you feel it's really necessary feel free to ack it.
> 
> should be applied on top of:
>    "hppa: drop RAM size fixup"
> ---
>   hw/hppa/machine.c | 22 ++++++++++++----------
>   1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/hppa/machine.c b/hw/hppa/machine.c
> index ebbf44f..7f8c92f 100644
> --- a/hw/hppa/machine.c
> +++ b/hw/hppa/machine.c
> @@ -54,6 +54,7 @@ static uint64_t cpu_hppa_to_phys(void *opaque, uint64_t addr)
>   
>   static HPPACPU *cpu[HPPA_MAX_CPUS];
>   static uint64_t firmware_entry;
> +static ram_addr_t clamped_ram_size;
>   
>   static void machine_hppa_init(MachineState *machine)
>   {
> @@ -74,8 +75,6 @@ static void machine_hppa_init(MachineState *machine)
>       long i;
>       unsigned int smp_cpus = machine->smp.cpus;
>   
> -    ram_size = machine->ram_size;
> -
>       /* Create CPUs.  */
>       for (i = 0; i < smp_cpus; i++) {
>           char *name = g_strdup_printf("cpu%ld-io-eir", i);
> @@ -90,10 +89,12 @@ static void machine_hppa_init(MachineState *machine)
>       }
>   
>       /* Limit main memory. */
> -    if (ram_size > FIRMWARE_START) {
> -        error_report("RAM size more than %d is not supported", FIRMWARE_START);
> +    if (machine->ram_size > 4 * GiB) {
> +        error_report("RAM size more than 4Gb is not supported");
>           exit(EXIT_FAILURE);
>       }
> +    clamped_ram_size = machine->ram_size > FIRMWARE_START ?
> +        FIRMWARE_START : machine->ram_size;
>   
>       memory_region_add_subregion(addr_space, 0, machine->ram);
>   
> @@ -151,7 +152,7 @@ static void machine_hppa_init(MachineState *machine)
>       qemu_log_mask(CPU_LOG_PAGE, "Firmware loaded at 0x%08" PRIx64
>                     "-0x%08" PRIx64 ", entry at 0x%08" PRIx64 ".\n",
>                     firmware_low, firmware_high, firmware_entry);
> -    if (firmware_low < ram_size || firmware_high >= FIRMWARE_END) {
> +    if (firmware_low < clamped_ram_size || firmware_high >= FIRMWARE_END) {
>           error_report("Firmware overlaps with memory or IO space");
>           exit(1);
>       }
> @@ -160,7 +161,8 @@ static void machine_hppa_init(MachineState *machine)
>       rom_region = g_new(MemoryRegion, 1);
>       memory_region_init_ram(rom_region, NULL, "firmware",
>                              (FIRMWARE_END - FIRMWARE_START), &error_fatal);
> -    memory_region_add_subregion(addr_space, FIRMWARE_START, rom_region);
> +    memory_region_add_subregion_overlap(addr_space, FIRMWARE_START, rom_region,
> +                                        1);

I don't think this is enough because we also have:

(qemu) info mtree
address-space: memory
   00000000f9000000-00000000f90007ff (prio 0, i/o): isa-io
   00000000fff80000-00000000fff80fff (prio 0, i/o): dino
   00000000fff83800-00000000fff83807 (prio 0, i/o): serial
   00000000fffb0000-00000000fffb0003 (prio 0, i/o): cpu0-io-eir

Which is why I went the other way around, using prio=-1 for the ram.

>   
>       /* Load kernel */
>       if (kernel_filename) {
> @@ -204,7 +206,7 @@ static void machine_hppa_init(MachineState *machine)
>                  (1) Due to sign-extension problems and PDC,
>                  put the initrd no higher than 1G.
>                  (2) Reserve 64k for stack.  */
> -            initrd_base = MIN(ram_size, 1 * GiB);
> +            initrd_base = MIN(clamped_ram_size, 1 * GiB);
>               initrd_base = initrd_base - 64 * KiB;
>               initrd_base = (initrd_base - initrd_size) & TARGET_PAGE_MASK;
>   
> @@ -232,7 +234,7 @@ static void machine_hppa_init(MachineState *machine)
>        * various parameters in registers. After firmware initialization,
>        * firmware will start the Linux kernel with ramdisk and cmdline.
>        */
> -    cpu[0]->env.gr[26] = ram_size;
> +    cpu[0]->env.gr[26] = clamped_ram_size;
>       cpu[0]->env.gr[25] = kernel_entry;
>   
>       /* tell firmware how many SMP CPUs to present in inventory table */
> @@ -255,11 +257,11 @@ static void hppa_machine_reset(MachineState *ms)
>       }
>   
>       /* already initialized by machine_hppa_init()? */
> -    if (cpu[0]->env.gr[26] == ram_size) {
> +    if (cpu[0]->env.gr[26] == clamped_ram_size) {
>           return;
>       }
>   
> -    cpu[0]->env.gr[26] = ram_size;
> +    cpu[0]->env.gr[26] = clamped_ram_size;
>       cpu[0]->env.gr[25] = 0; /* no firmware boot menu */
>       cpu[0]->env.gr[24] = 'c';
>       /* gr22/gr23 unused, no initrd while reboot. */
>