Re: [PATCH v3 04/10] hw/ppc/spapr: Use machine_memory_devices_init()

[Cédric Le Goater]

On 6/1/23 14:14, David Hildenbrand wrote:
> Let's use our new helper and stop always allocating ms->device_memory.
> There is no difference in common memory-device code anymore between
> ms->device_memory being NULL or the size being 0. So we only have to
> teach spapr code that ms->device_memory isn't always around.
>
> We can now modify two maxram_size checks to rely on ms->device_memory
> for detecting whether we have memory devices.
>
> Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
> Cc: "Cédric Le Goater" <clg@kaod.org>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Greg Kurz <groug@kaod.org>
> Cc: Harsh Prateek Bora <harshpb@linux.ibm.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.


> ---
>   hw/ppc/spapr.c       | 37 +++++++++++++++++++------------------
>   hw/ppc/spapr_hcall.c |  2 +-
>   2 files changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index dcb7f1c70a..b53aa4b5a8 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -546,10 +546,8 @@ static int 
> spapr_dt_dynamic_reconfiguration_memory(SpaprMachineState *spapr,
>                                   cpu_to_be32(lmb_size & 0xffffffff)};
>       MemoryDeviceInfoList *dimms = NULL;
>   
> -    /*
> -     * Don't create the node if there is no device memory
> -     */
> -    if (machine->ram_size == machine->maxram_size) {
> +    /* Don't create the node if there is no device memory. */
> +    if (!machine->device_memory) {
>           return 0;
>       }
>   
> @@ -859,16 +857,23 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
>       int rtas;
>       GString *hypertas = g_string_sized_new(256);
>       GString *qemu_hypertas = g_string_sized_new(256);
> -    uint64_t max_device_addr = MACHINE(spapr)->device_memory->base +
> -        memory_region_size(&MACHINE(spapr)->device_memory->mr);
>       uint32_t lrdr_capacity[] = {
> -        cpu_to_be32(max_device_addr >> 32),
> -        cpu_to_be32(max_device_addr & 0xffffffff),
> +        0,
> +        0,
>           cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE >> 32),
>           cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE & 0xffffffff),
>           cpu_to_be32(ms->smp.max_cpus / ms->smp.threads),
>       };
>   
> +    /* Do we have device memory? */
> +    if (MACHINE(spapr)->device_memory) {
> +        uint64_t max_device_addr = MACHINE(spapr)->device_memory->base +
> +            memory_region_size(&MACHINE(spapr)->device_memory->mr);
> +
> +        lrdr_capacity[0] = cpu_to_be32(max_device_addr >> 32);
> +        lrdr_capacity[1] = cpu_to_be32(max_device_addr & 0xffffffff);
> +    }
> +
>       _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));
>   
>       /* hypertas */
> @@ -2454,6 +2459,7 @@ static void 
> spapr_create_lmb_dr_connectors(SpaprMachineState *spapr)
>       uint32_t nr_lmbs = (machine->maxram_size - machine->ram_size)/lmb_size;
>       int i;
>   
> +    g_assert(!nr_lmbs || machine->device_memory);
>       for (i = 0; i < nr_lmbs; i++) {
>           uint64_t addr;
>   
> @@ -2866,12 +2872,11 @@ static void spapr_machine_init(MachineState *machine)
>       /* map RAM */
>       memory_region_add_subregion(sysmem, 0, machine->ram);
>   
> -    /* always allocate the device memory information */
> -    machine->device_memory = g_malloc0(sizeof(*machine->device_memory));
> -
>       /* initialize hotplug memory address space */
>       if (machine->ram_size < machine->maxram_size) {
>           ram_addr_t device_mem_size = machine->maxram_size - machine->ram_size;
> +        hwaddr device_mem_base;
> +
>           /*
>            * Limit the number of hotpluggable memory slots to half the number
>            * slots that KVM supports, leaving the other half for PCI and other
> @@ -2890,12 +2895,8 @@ static void spapr_machine_init(MachineState *machine)
>               exit(1);
>           }
>   
> -        machine->device_memory->base = ROUND_UP(machine->ram_size,
> -                                                SPAPR_DEVICE_MEM_ALIGN);
> -        memory_region_init(&machine->device_memory->mr, OBJECT(spapr),
> -                           "device-memory", device_mem_size);
> -        memory_region_add_subregion(sysmem, machine->device_memory->base,
> -                                    &machine->device_memory->mr);
> +        device_mem_base = ROUND_UP(machine->ram_size, SPAPR_DEVICE_MEM_ALIGN);
> +        machine_memory_devices_init(machine, device_mem_base, device_mem_size);
>       }
>   
>       if (smc->dr_lmb_enabled) {
> @@ -5109,7 +5110,7 @@ static bool phb_placement_2_7(SpaprMachineState *spapr, 
> uint32_t index,
>       int i;
>   
>       /* Do we have device memory? */
> -    if (MACHINE(spapr)->maxram_size > ram_top) {
> +    if (MACHINE(spapr)->device_memory) {
>           /* Can't just use maxram_size, because there may be an
>            * alignment gap between normal and device memory regions
>            */
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index b904755575..1dd32f340f 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -31,7 +31,7 @@ bool is_ram_address(SpaprMachineState *spapr, hwaddr addr)
>       if (addr < machine->ram_size) {
>           return true;
>       }
> -    if ((addr >= dms->base)
> +    if (dms && (addr >= dms->base)
>           && ((addr - dms->base) < memory_region_size(&dms->mr))) {
>           return true;
>       }