Re: [Qemu-devel] [PATCH 10/17] s390x: keep hint on virtio managing size

[Aurelien Jarno <aurelien@aurel32.net>]

On Fri, Apr 15, 2011 at 05:32:51PM +0200, Alexander Graf wrote:
> The s390x virtio bus keeps management information on virtio after the top
> of the guest's RAM. We need to be able to tell the guest the size of its
> RAM (without virtio stuff), but also be able to trap when the guest accesses
> RAM outside of its scope (including virtio stuff).
> 
> So we need a variable telling us the size of the virtio stuff, so we can
> calculate the highest available RAM address from that.
> 
> While at it, also increase the maximum number of virtio pages, so we play
> along well with more recent kernels that spawn a ridiculous number of virtio
> console adapters.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  hw/s390-virtio-bus.c |    3 +++
>  hw/s390-virtio-bus.h |    2 +-
>  target-s390x/cpu.h   |    3 +++
>  3 files changed, 7 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c
> index bb49e39..a90963b 100644
> --- a/hw/s390-virtio-bus.c
> +++ b/hw/s390-virtio-bus.c
> @@ -60,6 +60,9 @@ static const VirtIOBindings virtio_s390_bindings;
>  
>  static ram_addr_t s390_virtio_device_num_vq(VirtIOS390Device *dev);
>  
> +/* length of VirtIO device pages */
> +target_phys_addr_t virtio_size = S390_DEVICE_PAGES * TARGET_PAGE_SIZE;
> +

If this variable is never written, can it be declared const?

>  VirtIOS390Bus *s390_virtio_bus_init(ram_addr_t *ram_size)
>  {
>      VirtIOS390Bus *bus;
> diff --git a/hw/s390-virtio-bus.h b/hw/s390-virtio-bus.h
> index edf6d04..0c412d0 100644
> --- a/hw/s390-virtio-bus.h
> +++ b/hw/s390-virtio-bus.h
> @@ -33,7 +33,7 @@
>  #define VIRTIO_VQCONFIG_LEN		24
>  
>  #define VIRTIO_RING_LEN			(TARGET_PAGE_SIZE * 3)
> -#define S390_DEVICE_PAGES		256
> +#define S390_DEVICE_PAGES		512
>  
>  typedef struct VirtIOS390Device {
>      DeviceState qdev;
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index a84b3ee..6ba303d 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -293,6 +293,9 @@ void kvm_s390_interrupt_internal(CPUState *env, int type, uint32_t parm,
>                                   uint64_t parm64, int vm);
>  CPUState *s390_cpu_addr2state(uint16_t cpu_addr);
>  
> +/* from s390-virtio-bus */
> +extern target_phys_addr_t virtio_size;
> +
>  #ifndef KVM_S390_SIGP_STOP
>  #define KVM_S390_SIGP_STOP              0
>  #define KVM_S390_PROGRAM_INT            0


-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net