Re: [PATCH] kvm-userspace: Make PC speaker emulation aware of in-kernel PIT

[Avi Kivity <avi@xxxxxxxxxx>]

Jan Kiszka wrote:
> When using the in-kernel PIT the speaker emulation has to synchronize
> the PIT state with KVM. Enhance the existing speaker sound device and
> allow it to take over port 0x61 by using KVM_CREATE_PIT_NOSPKR when
> available. This unbreaks -soundhw pcspk in KVM mode.
>
> diff --git a/qemu/hw/pcspk.c b/qemu/hw/pcspk.c
> index ec1d0c6..4752518 100644
> --- a/qemu/hw/pcspk.c
> +++ b/qemu/hw/pcspk.c
> @@ -27,6 +27,8 @@
>  #include "isa.h"
>  #include "audio/audio.h"
>  #include "qemu-timer.h"
> +#include "i8254.h"
> +#include "qemu-kvm.h"
>  
>  #define PCSPK_BUF_LEN 1792
>  #define PCSPK_SAMPLE_RATE 32000
> @@ -71,7 +73,15 @@ static void pcspk_callback(void *opaque, int free)
>  {
>      PCSpkState *s = opaque;
>      unsigned int n;
> +#ifdef USE_KVM_PIT
> +    struct kvm_pit_state pit_state;
>  
> +    if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
> +        kvm_get_pit(kvm_context, &pit_state);
> +        s->pit->channels[2].mode = pit_state.channels[2].mode;
> +        s->pit->channels[2].count = pit_state.channels[2].count;
> +    }
> +#endif
>      if (pit_get_mode(s->pit, 2) != 3)
>          return;
>  
> @@ -120,7 +130,17 @@ static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
>  {
>      PCSpkState *s = opaque;
>      int out;
> -
> +#ifdef USE_KVM_PIT
> +    struct kvm_pit_state pit_state;
> +
> +    if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
> +        kvm_get_pit(kvm_context, &pit_state);
> +        s->pit->channels[2].mode = pit_state.channels[2].mode;
> +        s->pit->channels[2].count = pit_state.channels[2].count;
> +        s->pit->channels[2].count_load_time = pit_state.channels[2].count_load_time;
> +        s->pit->channels[2].gate = pit_state.channels[2].gate;
> +    }
> +#endif
>      s->dummy_refresh_clock ^= (1 << 4);
>      out = pit_get_out(s->pit, 2, qemu_get_clock(vm_clock)) << 5;
>  
> @@ -131,7 +151,17 @@ static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
>  {
>      PCSpkState *s = opaque;
>      const int gate = val & 1;
> -
> +#ifdef USE_KVM_PIT
> +    struct kvm_pit_state pit_state;
> +
> +    if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
> +        kvm_get_pit(kvm_context, &pit_state);
> +        s->pit->channels[2].mode = pit_state.channels[2].mode;
> +        s->pit->channels[2].count = pit_state.channels[2].count;
> +        s->pit->channels[2].count_load_time = pit_state.channels[2].count_load_time;
> +        s->pit->channels[2].gate = pit_state.channels[2].gate;
> +    }
> +#endif
>      s->data_on = (val >> 1) & 1;
>      pit_set_gate(s->pit, 2, gate);
>      if (s->voice) {
> @@ -139,6 +169,15 @@ static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
>              s->play_pos = 0;
>          AUD_set_active_out(s->voice, gate & s->data_on);
>      }
> +#ifdef USE_KVM_PIT
> +    if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
> +        pit_state.channels[2].mode = s->pit->channels[2].mode;
> +        pit_state.channels[2].count = s->pit->channels[2].count;
> +        pit_state.channels[2].count_load_time = s->pit->channels[2].count_load_time;
> +        pit_state.channels[2].gate = s->pit->channels[2].gate;
> +        kvm_set_pit(kvm_context, &pit_state);
> +    }
> +#endif
>  }
>  
>  void pcspk_init(PITState *pit)
>
>   

Please extract those bits into functions.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

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