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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86/vHPET: use rwlock instead of simple one
commit ded2100990d1688b96c2edc7221887c56c1a8e04
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Aug 11 15:00:15 2014 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Aug 11 15:00:15 2014 +0200
x86/vHPET: use rwlock instead of simple one
This namely benefits guests heavily reading the main counter, but not
touching the HPET much otherwise. Note that due to the way
hpet_get_comparator() works hpet_read() has to special cases reads from
the comparator registers and use a write lock there instead of the read
one used for all other registers.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/arch/x86/hvm/hpet.c | 42 +++++++++++++++++++++++++---------------
xen/arch/x86/hvm/vpt.c | 4 +-
xen/include/asm-x86/hvm/vpt.h | 2 +-
3 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
index 81ad0d6..bdfc6fc 100644
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -77,7 +77,7 @@
static inline uint64_t hpet_read_maincounter(HPETState *h, uint64_t guest_time)
{
- ASSERT(spin_is_locked(&h->lock));
+ ASSERT(rw_is_locked(&h->lock));
if ( hpet_enabled(h) )
return guest_time + h->mc_offset;
@@ -91,6 +91,8 @@ static uint64_t hpet_get_comparator(HPETState *h, unsigned
int tn,
uint64_t comparator;
uint64_t elapsed;
+ ASSERT(rw_is_write_locked(&h->lock));
+
comparator = h->hpet.comparator64[tn];
if ( hpet_enabled(h) && timer_is_periodic(h, tn) )
{
@@ -179,16 +181,24 @@ static int hpet_read(
goto out;
}
- spin_lock(&h->lock);
+ result = addr < HPET_Tn_CMP(0) ||
+ ((addr - HPET_Tn_CMP(0)) % (HPET_Tn_CMP(1) - HPET_Tn_CMP(0))) > 7;
+ if ( result )
+ read_lock(&h->lock);
+ else
+ write_lock(&h->lock);
val = hpet_read64(h, addr, guest_time_hpet(h));
+ if ( result )
+ read_unlock(&h->lock);
+ else
+ write_unlock(&h->lock);
+
result = val;
if ( length != 8 )
result = (val >> ((addr & 7) * 8)) & ((1ULL << (length * 8)) - 1);
- spin_unlock(&h->lock);
-
out:
*pval = result;
return X86EMUL_OKAY;
@@ -198,7 +208,7 @@ static void hpet_stop_timer(HPETState *h, unsigned int tn,
uint64_t guest_time)
{
ASSERT(tn < HPET_TIMER_NUM);
- ASSERT(spin_is_locked(&h->lock));
+ ASSERT(rw_is_write_locked(&h->lock));
TRACE_1D(TRC_HVM_EMUL_HPET_STOP_TIMER, tn);
destroy_periodic_time(&h->pt[tn]);
/* read the comparator to get it updated so a read while stopped will
@@ -218,7 +228,7 @@ static void hpet_set_timer(HPETState *h, unsigned int tn,
unsigned int oneshot;
ASSERT(tn < HPET_TIMER_NUM);
- ASSERT(spin_is_locked(&h->lock));
+ ASSERT(rw_is_write_locked(&h->lock));
if ( (tn == 0) && (h->hpet.config & HPET_CFG_LEGACY) )
{
@@ -304,7 +314,7 @@ static int hpet_write(
if ( hpet_check_access_length(addr, length) != 0 )
goto out;
- spin_lock(&h->lock);
+ write_lock(&h->lock);
guest_time = guest_time_hpet(h);
old_val = hpet_read64(h, addr, guest_time);
@@ -473,7 +483,7 @@ static int hpet_write(
#undef set_start_timer
#undef set_restart_timer
- spin_unlock(&h->lock);
+ write_unlock(&h->lock);
out:
return X86EMUL_OKAY;
@@ -499,7 +509,7 @@ static int hpet_save(struct domain *d, hvm_domain_context_t
*h)
int rc;
uint64_t guest_time;
- spin_lock(&hp->lock);
+ write_lock(&hp->lock);
guest_time = guest_time_hpet(hp);
/* Write the proper value into the main counter */
@@ -545,7 +555,7 @@ static int hpet_save(struct domain *d, hvm_domain_context_t
*h)
rec->timers[2].cmp = hp->hpet.comparator64[2];
}
- spin_unlock(&hp->lock);
+ write_unlock(&hp->lock);
return rc;
}
@@ -558,12 +568,12 @@ static int hpet_load(struct domain *d,
hvm_domain_context_t *h)
uint64_t guest_time;
int i;
- spin_lock(&hp->lock);
+ write_lock(&hp->lock);
/* Reload the HPET registers */
if ( _hvm_check_entry(h, HVM_SAVE_CODE(HPET), HVM_SAVE_LENGTH(HPET), 1) )
{
- spin_unlock(&hp->lock);
+ write_unlock(&hp->lock);
return -EINVAL;
}
@@ -604,7 +614,7 @@ static int hpet_load(struct domain *d, hvm_domain_context_t
*h)
if ( timer_enabled(hp, i) )
hpet_set_timer(hp, i, guest_time);
- spin_unlock(&hp->lock);
+ write_unlock(&hp->lock);
return 0;
}
@@ -618,7 +628,7 @@ void hpet_init(struct domain *d)
memset(h, 0, sizeof(HPETState));
- spin_lock_init(&h->lock);
+ rwlock_init(&h->lock);
h->stime_freq = S_TO_NS;
@@ -648,7 +658,7 @@ void hpet_deinit(struct domain *d)
int i;
HPETState *h = domain_vhpet(d);
- spin_lock(&h->lock);
+ write_lock(&h->lock);
if ( hpet_enabled(h) )
{
@@ -659,7 +669,7 @@ void hpet_deinit(struct domain *d)
hpet_stop_timer(h, i, guest_time);
}
- spin_unlock(&h->lock);
+ write_unlock(&h->lock);
}
void hpet_reset(struct domain *d)
diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 38541cf..7c6549c 100644
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -512,10 +512,10 @@ void pt_adjust_global_vcpu_target(struct vcpu *v)
pt_adjust_vcpu(&pl_time->vrtc.pt, v);
spin_unlock(&pl_time->vrtc.lock);
- spin_lock(&pl_time->vhpet.lock);
+ write_lock(&pl_time->vhpet.lock);
for ( i = 0; i < HPET_TIMER_NUM; i++ )
pt_adjust_vcpu(&pl_time->vhpet.pt[i], v);
- spin_unlock(&pl_time->vhpet.lock);
+ write_unlock(&pl_time->vhpet.lock);
}
diff --git a/xen/include/asm-x86/hvm/vpt.h b/xen/include/asm-x86/hvm/vpt.h
index 105fbdb..8b8b65a 100644
--- a/xen/include/asm-x86/hvm/vpt.h
+++ b/xen/include/asm-x86/hvm/vpt.h
@@ -96,7 +96,7 @@ typedef struct HPETState {
uint64_t hpet_to_ns_limit; /* max hpet ticks convertable to ns */
uint64_t mc_offset;
struct periodic_time pt[HPET_TIMER_NUM];
- spinlock_t lock;
+ rwlock_t lock;
} HPETState;
typedef struct RTCState {
--
generated by git-patchbot for /home/xen/git/xen.git#master
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