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_PIT2 where
available. This unbreaks -soundhw pcspk in KVM mode.
Changes in v4:
- preserve full PIT state across read-modify-write
- update kvm.h
Changes in v3:
- re-added incorrectly dropped kvm_enabled checks
Changes in v2:
- rebased over qemu-kvm and KVM_CREATE_PIT2
- refactored hooks in pcspk
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
hw/pcspk.c | 48 ++++++++++++++++++++++++++++++++++++++++
kvm/kernel/include/linux/kvm.h | 10 ++++++++
kvm/libkvm/libkvm-x86.c | 26 +++++++++++++++-------
3 files changed, 76 insertions(+), 8 deletions(-)
diff --git a/hw/pcspk.c b/hw/pcspk.c
index ec1d0c6..c0b8347 100644
--- a/hw/pcspk.c
+++ b/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
@@ -48,6 +50,43 @@ typedef struct {
static const char *s_spk = "pcspk";
static PCSpkState pcspk_state;
+#ifdef USE_KVM_PIT
+static void kvm_get_pit_ch2(PITState *pit,
+ struct kvm_pit_state *inkernel_state)
+{
+ struct kvm_pit_state pit_state;
+
+ if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
+ kvm_get_pit(kvm_context, &pit_state);
+ pit->channels[2].mode = pit_state.channels[2].mode;
+ pit->channels[2].count = pit_state.channels[2].count;
+ pit->channels[2].count_load_time = pit_state.channels[2].count_load_time;
+ pit->channels[2].gate = pit_state.channels[2].gate;
+ if (inkernel_state) {
+ memcpy(inkernel_state, &pit_state, sizeof(*inkernel_state));
+ }
+ }
+}
+
+static void kvm_set_pit_ch2(PITState *pit,
+ struct kvm_pit_state *inkernel_state)
+{
+ if (kvm_enabled() && qemu_kvm_pit_in_kernel()) {
+ inkernel_state->channels[2].mode = pit->channels[2].mode;
+ inkernel_state->channels[2].count = pit->channels[2].count;
+ inkernel_state->channels[2].count_load_time =
+ pit->channels[2].count_load_time;
+ inkernel_state->channels[2].gate = pit->channels[2].gate;
+ kvm_set_pit(kvm_context, inkernel_state);
+ }
+}
+#else
+static inline void kvm_get_pit_ch2(PITState *pit,
+ kvm_pit_state *inkernel_state) { }
+static inline void kvm_set_pit_ch2(PITState *pit,
+ kvm_pit_state *inkernel_state) { }
+#endif
+
static inline void generate_samples(PCSpkState *s)
{
unsigned int i;
@@ -72,6 +111,8 @@ static void pcspk_callback(void *opaque, int free)
PCSpkState *s = opaque;
unsigned int n;
+ kvm_get_pit_ch2(s->pit, NULL);
+
if (pit_get_mode(s->pit, 2) != 3)
return;
@@ -121,6 +162,8 @@ static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
PCSpkState *s = opaque;
int out;
+ kvm_get_pit_ch2(s->pit, NULL);
+
s->dummy_refresh_clock ^= (1 << 4);
out = pit_get_out(s->pit, 2, qemu_get_clock(vm_clock)) << 5;
@@ -129,9 +172,12 @@ static uint32_t pcspk_ioport_read(void *opaque, uint32_t addr)
static void pcspk_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
+ struct kvm_pit_state inkernel_state;
PCSpkState *s = opaque;
const int gate = val & 1;
+ kvm_get_pit_ch2(s->pit, &inkernel_state);
+
s->data_on = (val >> 1) & 1;
pit_set_gate(s->pit, 2, gate);
if (s->voice) {
@@ -139,6 +185,8 @@ 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);
}
+
+ kvm_set_pit_ch2(s->pit, &inkernel_state);
}
void pcspk_init(PITState *pit)
diff --git a/kvm/kernel/include/linux/kvm.h b/kvm/kernel/include/linux/kvm.h
index f5e9d66..5b4b90c 100644
--- a/kvm/kernel/include/linux/kvm.h
+++ b/kvm/kernel/include/linux/kvm.h
@@ -110,6 +110,14 @@ struct kvm_irqchip {
} chip;
};
+/* for KVM_CREATE_PIT2 */
+struct kvm_pit_config {
+ __u32 flags;
+ __u32 pad[15];
+};
+
+#define KVM_PIT_SPEAKER_DUMMY 1
+
#define KVM_EXIT_UNKNOWN 0
#define KVM_EXIT_EXCEPTION 1
#define KVM_EXIT_IO 2
@@ -455,6 +463,7 @@ struct kvm_trace_rec {
#define KVM_CAP_ASSIGN_DEV_IRQ 29
/* Another bug in KVM_SET_USER_MEMORY_REGION fixed: */
#define KVM_CAP_JOIN_MEMORY_REGIONS_WORKS 30
+#define KVM_CAP_PIT2 31
#ifdef KVM_CAP_IRQ_ROUTING
@@ -538,6 +547,7 @@ struct kvm_irq_routing {
#define KVM_ASSIGN_SET_MSIX_ENTRY \
_IOW(KVMIO, 0x74, struct kvm_assigned_msix_entry)
#define KVM_DEASSIGN_DEV_IRQ _IOW(KVMIO, 0x75, struct kvm_assigned_irq)
+#define KVM_CREATE_PIT2 _IOW(KVMIO, 0x76, struct kvm_pit_config)
/*
* ioctls for vcpu fds
diff --git a/kvm/libkvm/libkvm-x86.c b/kvm/libkvm/libkvm-x86.c
index a2f6320..9c0d967 100644
--- a/kvm/libkvm/libkvm-x86.c
+++ b/kvm/libkvm/libkvm-x86.c
@@ -59,16 +59,26 @@ static int kvm_create_pit(kvm_context_t kvm)
kvm->pit_in_kernel = 0;
if (!kvm->no_pit_creation) {
- r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_PIT);
- if (r > 0) {
+#ifdef KVM_CAP_PIT2
+ struct kvm_pit_config config = { .flags = 0 };
+
+ r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_PIT2);
+ if (r > 0)
+ r = ioctl(kvm->vm_fd, KVM_CREATE_PIT2, &config);
+ else
+#endif
+ {
+ r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_PIT);
+ if (r <= 0)
+ return 0;
+
r = ioctl(kvm->vm_fd, KVM_CREATE_PIT);
- if (r >= 0)
- kvm->pit_in_kernel = 1;
- else {
- fprintf(stderr, "Create kernel PIC irqchip failed\n");
- return r;
- }
}
+ if (r < 0) {
+ fprintf(stderr, "Create kernel PIC irqchip failed\n");
+ return r;
+ }
+ kvm->pit_in_kernel = 1;
}
#endif
return 0;
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