Re: [Qemu-devel] [PATCH 4/8] [PATCH RFC v3] s390-qemu: cpu hotplug - Storage key global access

[Alexander Graf]

On 01.08.2013, at 16:12, Jason J. Herne wrote:

> From: "Jason J. Herne" <address@hidden>
> 
> Introduces global access to storage key data so we can set it for each cpu in
> the S390 cpu initialization routine.
> 
> Signed-off-by: Jason J. Herne <address@hidden>
> ---
> hw/s390x/s390-virtio-ccw.c |    5 ++---
> hw/s390x/s390-virtio.c     |   21 ++++++++++++++++-----
> hw/s390x/s390-virtio.h     |    2 +-
> target-s390x/cpu.h         |    4 ++++
> 4 files changed, 23 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index aebbbf1..b469960 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -65,7 +65,6 @@ static void ccw_init(QEMUMachineInitArgs *args)
>     MemoryRegion *sysmem = get_system_memory();
>     MemoryRegion *ram = g_new(MemoryRegion, 1);
>     int shift = 0;
> -    uint8_t *storage_keys;
>     int ret;
>     VirtualCssBus *css_bus;
> 
> @@ -94,10 +93,10 @@ static void ccw_init(QEMUMachineInitArgs *args)
>     memory_region_add_subregion(sysmem, 0, ram);
> 
>     /* allocate storage keys */
> -    storage_keys = g_malloc0(my_ram_size / TARGET_PAGE_SIZE);
> +    s390_alloc_storage_keys(my_ram_size);
> 
>     /* init CPUs */
> -    s390_init_cpus(args->cpu_model, storage_keys);
> +    s390_init_cpus(args->cpu_model);
> 
>     if (kvm_enabled()) {
>         kvm_s390_enable_css_support(s390_cpu_addr2state(0));
> diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
> index 439d732..21e9124 100644
> --- a/hw/s390x/s390-virtio.c
> +++ b/hw/s390x/s390-virtio.c
> @@ -123,6 +123,18 @@ static void s390_virtio_register_hcalls(void)
>                                    s390_virtio_hcall_set_status);
> }
> 
> +static uint8_t *storage_keys;
> +
> +uint8_t *s390_get_storage_keys(void)
> +{
> +    return storage_keys;

This is basically the same as having a global in my point of view. I would 
personally just make it a global and call it a day.

However, it might make sense to make storage keys be a device. That way you get 
direct access for free (you can ask for the device by-path) and you have 
somewhere to hook migration off of.


Alex

> +}
> +
> +void s390_alloc_storage_keys(ram_addr_t ram_size)
> +{
> +    storage_keys = g_malloc0(ram_size / TARGET_PAGE_SIZE);
> +}
> +
> /*
>  * The number of running CPUs. On s390 a shutdown is the state of all CPUs
>  * being either stopped or disabled (for interrupts) waiting. We have to
> @@ -176,7 +188,7 @@ void s390_init_ipl_dev(const char *kernel_filename,
>     qdev_init_nofail(dev);
> }
> 
> -void s390_init_cpus(const char *cpu_model, uint8_t *storage_keys)
> +void s390_init_cpus(const char *cpu_model)
> {
>     int i;
> 
> @@ -196,7 +208,7 @@ void s390_init_cpus(const char *cpu_model, uint8_t 
> *storage_keys)
>         ipi_states[i] = cpu;
>         cs->halted = 1;
>         cpu->env.exception_index = EXCP_HLT;
> -        cpu->env.storage_keys = storage_keys;
> +        cpu->env.storage_keys = s390_get_storage_keys();
>     }
> }
> 
> @@ -231,7 +243,6 @@ static void s390_init(QEMUMachineInitArgs *args)
>     MemoryRegion *sysmem = get_system_memory();
>     MemoryRegion *ram = g_new(MemoryRegion, 1);
>     int shift = 0;
> -    uint8_t *storage_keys;
>     void *virtio_region;
>     hwaddr virtio_region_len;
>     hwaddr virtio_region_start;
> @@ -270,10 +281,10 @@ static void s390_init(QEMUMachineInitArgs *args)
>                               virtio_region_len);
> 
>     /* allocate storage keys */
> -    storage_keys = g_malloc0(my_ram_size / TARGET_PAGE_SIZE);
> +    s390_alloc_storage_keys(my_ram_size);
> 
>     /* init CPUs */
> -    s390_init_cpus(args->cpu_model, storage_keys);
> +    s390_init_cpus(args->cpu_model);
> 
>     /* Create VirtIO network adapters */
>     s390_create_virtio_net((BusState *)s390_bus, "virtio-net-s390");
> diff --git a/hw/s390x/s390-virtio.h b/hw/s390x/s390-virtio.h
> index 5c405e7..c1cb042 100644
> --- a/hw/s390x/s390-virtio.h
> +++ b/hw/s390x/s390-virtio.h
> @@ -20,7 +20,7 @@
> typedef int (*s390_virtio_fn)(const uint64_t *args);
> void s390_register_virtio_hypercall(uint64_t code, s390_virtio_fn fn);
> 
> -void s390_init_cpus(const char *cpu_model, uint8_t *storage_keys);
> +void s390_init_cpus(const char *cpu_model);
> void s390_init_ipl_dev(const char *kernel_filename,
>                        const char *kernel_cmdline,
>                        const char *initrd_filename,
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index 65bef86..877eac7 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -374,6 +374,10 @@ static inline void kvm_s390_interrupt_internal(S390CPU 
> *cpu, int type,
> {
> }
> #endif
> +
> +uint8_t *s390_get_storage_keys(void);
> +void s390_alloc_storage_keys(ram_addr_t ram_size);
> +
> S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
> void s390_add_running_cpu(S390CPU *cpu);
> unsigned s390_del_running_cpu(S390CPU *cpu);
> -- 
> 1.7.10.4
>