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

[Jan Kiszka <jan.kiszka@xxxxxx>]

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.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---

 libkvm/libkvm-x86.c |   13 +++++++++++++
 qemu/hw/pcspk.c     |   43 +++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/libkvm/libkvm-x86.c b/libkvm/libkvm-x86.c
index 2fc4fce..03b1939 100644
--- a/libkvm/libkvm-x86.c
+++ b/libkvm/libkvm-x86.c
@@ -59,6 +59,19 @@ int kvm_create_pit(kvm_context_t kvm)
 
 	kvm->pit_in_kernel = 0;
 	if (!kvm->no_pit_creation) {
+#ifdef KVM_CAP_PIT_NOSPKR
+		r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_PIT_NOSPKR);
+		if (r > 0) {
+			r = ioctl(kvm->vm_fd, KVM_CREATE_PIT_NOSPKR);
+			if (r >= 0) {
+				kvm->pit_in_kernel = 1;
+				return 0;
+			} else {
+				fprintf(stderr, "Create kernel PIC irqchip failed\n");
+				return r;
+			}
+		}
+#endif
 		r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_PIT);
 		if (r > 0) {
 			r = ioctl(kvm->vm_fd, KVM_CREATE_PIT);
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)

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