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Re: [Qemu-devel] [patch v4 09/16] memory: introduce mmio request pending
From: |
liu ping fan |
Subject: |
Re: [Qemu-devel] [patch v4 09/16] memory: introduce mmio request pending to anti nested DMA |
Date: |
Wed, 24 Oct 2012 14:31:14 +0800 |
On Tue, Oct 23, 2012 at 8:38 PM, Gleb Natapov <address@hidden> wrote:
> On Mon, Oct 22, 2012 at 05:23:52PM +0800, Liu Ping Fan wrote:
>> Rejecting the nested mmio request which does not aim at RAM, so we
>> can avoid the potential deadlock caused by the random lock sequence
>> of two device's local lock.
>>
>> Signed-off-by: Liu Ping Fan <address@hidden>
>> ---
>> cpus.c | 14 ++++++++++++++
>> exec.c | 50
>> ++++++++++++++++++++++++++++++++++++--------------
>> hw/hw.h | 1 +
>> kvm-all.c | 2 ++
>> qemu-thread-posix.h | 3 +++
>> qemu-thread.h | 2 ++
>> 6 files changed, 58 insertions(+), 14 deletions(-)
>>
>> diff --git a/cpus.c b/cpus.c
>> index 4cd7f85..365a512 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>> @@ -729,6 +729,18 @@ static void qemu_kvm_wait_io_event(CPUArchState *env)
>> qemu_wait_io_event_common(env);
>> }
>>
>> +int get_context_type(void)
>> +{
>> + QemuThread *t = pthread_getspecific(qemu_thread_key);
>> + return t->context_type;
>> +}
>> +
> You defined the function but not use it.
>
> What 0/1 context_type means?
>
Will s/t->context/get_context_type/ . The context_type is just for
device's function to tell whether it is called by local lock or
biglock. 0 is initial value, 1 is under mmio dispatching, 2 is under
io dispatching. Will use enum to define them.
Regards,
pingfan
>> +void set_context_type(int type)
>> +{
>> + QemuThread *t = pthread_getspecific(qemu_thread_key);
>> + t->context_type = type;
>> +}
>> +
>> static void *qemu_kvm_cpu_thread_fn(void *arg)
>> {
>> CPUArchState *env = arg;
>> @@ -736,6 +748,8 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
>> int r;
>>
>> pthread_setspecific(qemu_thread_key, cpu->thread);
>> + set_context_type(0);
>> +
>> qemu_mutex_lock(&qemu_global_mutex);
>> qemu_thread_get_self(cpu->thread);
>> env->thread_id = qemu_get_thread_id();
>> diff --git a/exec.c b/exec.c
>> index 91b859b..a0327a1 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -3490,7 +3490,9 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> uint32_t val;
>> target_phys_addr_t page;
>> MemoryRegionSection *section, obj_mrs;
>> - int safe_ref;
>> + int safe_ref, nested_dma = 0;
>> + QemuThread *thread = pthread_getspecific(qemu_thread_key);
>> + int context = thread->context_type;
>>
>> while (len > 0) {
>> page = addr & TARGET_PAGE_MASK;
>> @@ -3500,7 +3502,8 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> qemu_mutex_lock(&mem_map_lock);
>> safe_ref = phys_page_lookup(page, &obj_mrs);
>> qemu_mutex_unlock(&mem_map_lock);
>> - if (safe_ref == 0) {
>> +
>> + if (safe_ref == 0 && context == 1) {
>> qemu_mutex_lock_iothread();
>> qemu_mutex_lock(&mem_map_lock);
>> /* At the 2nd try, mem map can change, so need to judge it
>> again */
>> @@ -3511,7 +3514,9 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> }
>> }
>> section = &obj_mrs;
>> -
>> + if (context == 1) {
>> + nested_dma = thread->mmio_request_pending++ > 1 ? 1 : 0;
>> + }
>> if (is_write) {
>> if (!memory_region_is_ram(section->mr)) {
>> target_phys_addr_t addr1;
>> @@ -3521,17 +3526,23 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> if (l >= 4 && ((addr1 & 3) == 0)) {
>> /* 32 bit write access */
>> val = ldl_p(buf);
>> - io_mem_write(section->mr, addr1, val, 4);
>> + if (!nested_dma) {
>> + io_mem_write(section->mr, addr1, val, 4);
>> + }
>> l = 4;
>> } else if (l >= 2 && ((addr1 & 1) == 0)) {
>> /* 16 bit write access */
>> val = lduw_p(buf);
>> - io_mem_write(section->mr, addr1, val, 2);
>> + if (!nested_dma) {
>> + io_mem_write(section->mr, addr1, val, 2);
>> + }
>> l = 2;
>> } else {
>> /* 8 bit write access */
>> val = ldub_p(buf);
>> - io_mem_write(section->mr, addr1, val, 1);
>> + if (!nested_dma) {
>> + io_mem_write(section->mr, addr1, val, 1);
>> + }
>> l = 1;
>> }
>> } else if (!section->readonly) {
>> @@ -3552,24 +3563,31 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> }
>> } else {
>> if (!(memory_region_is_ram(section->mr) ||
>> - memory_region_is_romd(section->mr))) {
>> + memory_region_is_romd(section->mr)) &&
>> + !nested_dma) {
>> target_phys_addr_t addr1;
>> /* I/O case */
>> addr1 = memory_region_section_addr(section, addr);
>> if (l >= 4 && ((addr1 & 3) == 0)) {
>> /* 32 bit read access */
>> - val = io_mem_read(section->mr, addr1, 4);
>> - stl_p(buf, val);
>> + if (!nested_dma) {
>> + val = io_mem_read(section->mr, addr1, 4);
>> + stl_p(buf, val);
>> + }
>> l = 4;
>> } else if (l >= 2 && ((addr1 & 1) == 0)) {
>> /* 16 bit read access */
>> - val = io_mem_read(section->mr, addr1, 2);
>> - stw_p(buf, val);
>> + if (!nested_dma) {
>> + val = io_mem_read(section->mr, addr1, 2);
>> + stw_p(buf, val);
>> + }
>> l = 2;
>> } else {
>> /* 8 bit read access */
>> - val = io_mem_read(section->mr, addr1, 1);
>> - stb_p(buf, val);
>> + if (!nested_dma) {
>> + val = io_mem_read(section->mr, addr1, 1);
>> + stb_p(buf, val);
>> + }
>> l = 1;
>> }
>> } else {
>> @@ -3586,7 +3604,11 @@ void cpu_physical_memory_rw(target_phys_addr_t addr,
>> uint8_t *buf,
>> len -= l;
>> buf += l;
>> addr += l;
>> - if (safe_ref == 0) {
>> +
>> + if (context == 1) {
>> + thread->mmio_request_pending--;
>> + }
>> + if (safe_ref == 0 && context == 1) {
>> qemu_mutex_unlock_iothread();
>> }
>> }
>> diff --git a/hw/hw.h b/hw/hw.h
>> index e5cb9bf..935b045 100644
>> --- a/hw/hw.h
>> +++ b/hw/hw.h
>> @@ -12,6 +12,7 @@
>> #include "irq.h"
>> #include "qemu-file.h"
>> #include "vmstate.h"
>> +#include "qemu-thread.h"
>>
>> #ifdef NEED_CPU_H
>> #if TARGET_LONG_BITS == 64
>> diff --git a/kvm-all.c b/kvm-all.c
>> index 34b02c1..b3fa597 100644
>> --- a/kvm-all.c
>> +++ b/kvm-all.c
>> @@ -1562,10 +1562,12 @@ int kvm_cpu_exec(CPUArchState *env)
>> break;
>> case KVM_EXIT_MMIO:
>> DPRINTF("handle_mmio\n");
>> + set_context_type(1);
>> cpu_physical_memory_rw(run->mmio.phys_addr,
>> run->mmio.data,
>> run->mmio.len,
>> run->mmio.is_write);
>> + set_context_type(0);
>> ret = 0;
>> break;
>> case KVM_EXIT_IRQ_WINDOW_OPEN:
>> diff --git a/qemu-thread-posix.h b/qemu-thread-posix.h
>> index 2607b1c..9fcc6f8 100644
>> --- a/qemu-thread-posix.h
>> +++ b/qemu-thread-posix.h
>> @@ -12,6 +12,9 @@ struct QemuCond {
>>
>> struct QemuThread {
>> pthread_t thread;
>> + /* 0 clean; 1 mmio; 2 io */
>> + int context_type;
>> + int mmio_request_pending;
>> };
>>
>> extern pthread_key_t qemu_thread_key;
>> diff --git a/qemu-thread.h b/qemu-thread.h
>> index 4a6427d..88eaf94 100644
>> --- a/qemu-thread.h
>> +++ b/qemu-thread.h
>> @@ -45,6 +45,8 @@ void *qemu_thread_join(QemuThread *thread);
>> void qemu_thread_get_self(QemuThread *thread);
>> bool qemu_thread_is_self(QemuThread *thread);
>> void qemu_thread_exit(void *retval);
>> +int get_context_type(void);
>> +void set_context_type(int type);
>>
>> void qemu_thread_key_create(void);
>> #endif
>> --
>> 1.7.4.4
>>
>
> --
> Gleb.
>
- Re: [Qemu-devel] [patch v4 10/16] memory: introduce lock ops for MemoryRegionOps, (continued)
[Qemu-devel] [patch v4 14/16] qdev: introduce stopping state, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 07/16] memory: make mmio dispatch able to be out of biglock, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 09/16] memory: introduce mmio request pending to anti nested DMA, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 04/16] pci: remove pci device from mem view when unplug, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 06/16] memory: document ref, unref interface, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Liu Ping Fan, 2012/10/22
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Avi Kivity, 2012/10/22
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Paolo Bonzini, 2012/10/23
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Avi Kivity, 2012/10/23
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Paolo Bonzini, 2012/10/23
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Avi Kivity, 2012/10/23
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Paolo Bonzini, 2012/10/23
- Re: [Qemu-devel] [patch v4 05/16] memory: introduce ref, unref interface for MemoryRegionOps, Avi Kivity, 2012/10/23