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hpet: switch to fine-grained device locking

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as a step towards lock-less HPET counter read,
use per device locking instead of BQL.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20250814160600.2327672-4-imammedo@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Igor Mammedov 2025-08-14 18:05:55 +02:00 • committed by Paolo Bonzini
parent 4ae5e2b2bf
commit 7defb58baf
1 changed files with 6 additions and 0 deletions
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6
hw/timer/hpet.c
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@ -38,6 +38,7 @@
#include "hw/timer/i8254.h"
#include "system/address-spaces.h"
#include "qom/object.h"
#include "qemu/lockable.h"
#include "trace.h"
struct hpet_fw_config hpet_fw_cfg = {.count = UINT8_MAX};
@ -69,6 +70,7 @@ struct HPETState {
SysBusDevice parent_obj;
/*< public >*/
QemuMutex lock;
MemoryRegion iomem;
uint64_t hpet_offset;
bool hpet_offset_saved;
@ -428,6 +430,7 @@ static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
trace_hpet_ram_read(addr);
addr &= ~4;
QEMU_LOCK_GUARD(&s->lock);
/*address range of all global regs*/
if (addr <= 0xff) {
switch (addr) {
@ -482,6 +485,7 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
int len = MIN(size * 8, 64 - shift);
uint64_t old_val, new_val, cleared;
QEMU_LOCK_GUARD(&s->lock);
trace_hpet_ram_write(addr, value);
addr &= ~4;
@ -679,8 +683,10 @@ static void hpet_init(Object *obj)
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
HPETState *s = HPET(obj);
qemu_mutex_init(&s->lock);
/* HPET Area */
memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
memory_region_enable_lockless_io(&s->iomem);
sysbus_init_mmio(sbd, &s->iomem);
}