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Re: [Qemu-devel] [PATCH 5/9] memory: let address_space_rw/ld*/st* run ou
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 5/9] memory: let address_space_rw/ld*/st* run outside the BQL |
Date: |
Thu, 25 Jun 2015 09:47:29 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 |
On 25/06/2015 07:11, Fam Zheng wrote:
> On Wed, 06/24 18:25, Paolo Bonzini wrote:
>> From: Jan Kiszka <address@hidden>
>>
>> The MMIO case is further broken up in two cases: if the caller does not
>> hold the BQL on invocation, the unlocked one takes or avoids BQL depending
>> on the locking strategy of the target memory region and its coalesced
>> MMIO handling. In this case, the caller should not hold _any_ lock
>> (a friendly suggestion which is disregarded by virtio-scsi-dataplane).
>>
>> Signed-off-by: Jan Kiszka <address@hidden>
>> Cc: Frederic Konrad <address@hidden>
>> Message-Id: <address@hidden>
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> ---
>> exec.c | 69
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
>> 1 file changed, 60 insertions(+), 9 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index f2e6603..fd0401e 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -48,6 +48,7 @@
>> #endif
>> #include "exec/cpu-all.h"
>> #include "qemu/rcu_queue.h"
>> +#include "qemu/main-loop.h"
>> #include "exec/cputlb.h"
>> #include "translate-all.h"
>>
>> @@ -2316,11 +2317,27 @@ static int memory_access_size(MemoryRegion *mr,
>> unsigned l, hwaddr addr)
>> return l;
>> }
>>
>> -static void prepare_mmio_access(MemoryRegion *mr)
>> +static bool prepare_mmio_access(MemoryRegion *mr)
>> {
>> + bool unlocked = !qemu_mutex_iothread_locked();
>> + bool release_lock = false;
>> +
>> + if (unlocked && mr->global_locking) {
>> + qemu_mutex_lock_iothread();
>> + unlocked = false;
>> + release_lock = true;
>> + }
>> if (mr->flush_coalesced_mmio) {
>> + if (unlocked) {
>> + qemu_mutex_lock_iothread();
>> + }
>> qemu_flush_coalesced_mmio_buffer();
>> + if (unlocked) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> }
>> +
>> + return release_lock;
>> }
>>
>> MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, MemTxAttrs
>> attrs,
>> @@ -2332,6 +2349,7 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr
>> addr, MemTxAttrs attrs,
>> hwaddr addr1;
>> MemoryRegion *mr;
>> MemTxResult result = MEMTX_OK;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> while (len > 0) {
>> @@ -2340,7 +2358,7 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr
>> addr, MemTxAttrs attrs,
>>
>> if (is_write) {
>> if (!memory_access_is_direct(mr, is_write)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>> l = memory_access_size(mr, l, addr1);
>> /* XXX: could force current_cpu to NULL to avoid
>> potential bugs */
>> @@ -2382,7 +2400,7 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr
>> addr, MemTxAttrs attrs,
>> } else {
>> if (!memory_access_is_direct(mr, is_write)) {
>> /* I/O case */
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>> l = memory_access_size(mr, l, addr1);
>> switch (l) {
>> case 8:
>> @@ -2418,6 +2436,12 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr
>> addr, MemTxAttrs attrs,
>> memcpy(buf, ptr, l);
>> }
>> }
>> +
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + release_lock = false;
>> + }
>> +
>> len -= l;
>> buf += l;
>> addr += l;
>> @@ -2744,11 +2768,12 @@ static inline uint32_t
>> address_space_ldl_internal(AddressSpace *as, hwaddr addr,
>> hwaddr l = 4;
>> hwaddr addr1;
>> MemTxResult r;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l, false);
>> if (l < 4 || !memory_access_is_direct(mr, false)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> /* I/O case */
>> r = memory_region_dispatch_read(mr, addr1, &val, 4, attrs);
>> @@ -2782,6 +2807,9 @@ static inline uint32_t
>> address_space_ldl_internal(AddressSpace *as, hwaddr addr,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> rcu_read_unlock();
>> return val;
>> }
>> @@ -2834,12 +2862,13 @@ static inline uint64_t
>> address_space_ldq_internal(AddressSpace *as, hwaddr addr,
>> hwaddr l = 8;
>> hwaddr addr1;
>> MemTxResult r;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l,
>> false);
>> if (l < 8 || !memory_access_is_direct(mr, false)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> /* I/O case */
>> r = memory_region_dispatch_read(mr, addr1, &val, 8, attrs);
>> @@ -2873,6 +2902,9 @@ static inline uint64_t
>> address_space_ldq_internal(AddressSpace *as, hwaddr addr,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> rcu_read_unlock();
>> return val;
>> }
>> @@ -2945,12 +2977,13 @@ static inline uint32_t
>> address_space_lduw_internal(AddressSpace *as,
>> hwaddr l = 2;
>> hwaddr addr1;
>> MemTxResult r;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l,
>> false);
>> if (l < 2 || !memory_access_is_direct(mr, false)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> /* I/O case */
>> r = memory_region_dispatch_read(mr, addr1, &val, 2, attrs);
>> @@ -2984,6 +3017,9 @@ static inline uint32_t
>> address_space_lduw_internal(AddressSpace *as,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> rcu_read_unlock();
>> return val;
>> }
>> @@ -3036,12 +3072,13 @@ void address_space_stl_notdirty(AddressSpace *as,
>> hwaddr addr, uint32_t val,
>> hwaddr addr1;
>> MemTxResult r;
>> uint8_t dirty_log_mask;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l,
>> true);
>> if (l < 4 || !memory_access_is_direct(mr, true)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> r = memory_region_dispatch_write(mr, addr1, val, 4, attrs);
>> } else {
>> @@ -3057,6 +3094,9 @@ void address_space_stl_notdirty(AddressSpace *as,
>> hwaddr addr, uint32_t val,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> rcu_read_unlock();
>> }
>>
>> @@ -3077,12 +3117,13 @@ static inline void
>> address_space_stl_internal(AddressSpace *as,
>> hwaddr l = 4;
>> hwaddr addr1;
>> MemTxResult r;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l,
>> true);
>> if (l < 4 || !memory_access_is_direct(mr, true)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> #if defined(TARGET_WORDS_BIGENDIAN)
>> if (endian == DEVICE_LITTLE_ENDIAN) {
>> @@ -3115,6 +3156,9 @@ static inline void
>> address_space_stl_internal(AddressSpace *as,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> rcu_read_unlock();
>> }
>>
>> @@ -3184,11 +3228,12 @@ static inline void
>> address_space_stw_internal(AddressSpace *as,
>> hwaddr l = 2;
>> hwaddr addr1;
>> MemTxResult r;
>> + bool release_lock = false;
>>
>> rcu_read_lock();
>> mr = address_space_translate(as, addr, &addr1, &l, true);
>> if (l < 2 || !memory_access_is_direct(mr, true)) {
>> - prepare_mmio_access(mr);
>> + release_lock |= prepare_mmio_access(mr);
>>
>> #if defined(TARGET_WORDS_BIGENDIAN)
>> if (endian == DEVICE_LITTLE_ENDIAN) {
>> @@ -3221,6 +3266,12 @@ static inline void
>> address_space_stw_internal(AddressSpace *as,
>> if (result) {
>> *result = r;
>> }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>> + if (release_lock) {
>> + qemu_mutex_unlock_iothread();
>> + }
>
> Bad rebase?
Yes.
Paolo
- Re: [Qemu-devel] [PATCH 3/9] memory: Add global-locking property to memory regions, (continued)
[Qemu-devel] [PATCH 4/9] exec: pull qemu_flush_coalesced_mmio_buffer() into address_space_rw/ld*/st*, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 1/9] main-loop: use qemu_mutex_lock_iothread consistently, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 2/9] main-loop: introduce qemu_mutex_iothread_locked, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 5/9] memory: let address_space_rw/ld*/st* run outside the BQL, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 7/9] kvm: Switch to unlocked PIO, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 8/9] acpi: mark PMTIMER as unlocked, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 9/9] kvm: Switch to unlocked MMIO, Paolo Bonzini, 2015/06/24
[Qemu-devel] [PATCH 6/9] kvm: First step to push iothread lock out of inner run loop, Paolo Bonzini, 2015/06/24