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[Qemu-devel] [PULL 14/19] kvm: First step to push iothread lock out of i
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 14/19] kvm: First step to push iothread lock out of inner run loop |
Date: |
Mon, 6 Jul 2015 14:35:03 +0200 |
From: Jan Kiszka <address@hidden>
This opens the path to get rid of the iothread lock on vmexits in KVM
mode. On x86, the in-kernel irqchips has to be used because we otherwise
need to synchronize APIC and other per-cpu state accesses that could be
changed concurrently.
Regarding pre/post-run callbacks, s390x and ARM should be fine without
specific locking as the callbacks are empty. MIPS and POWER require
locking for the pre-run callback.
For the handle_exit callback, it is non-empty in x86, POWER and s390.
Some POWER cases could do without the locking, but it is left in
place for now.
Signed-off-by: Jan Kiszka <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Message-Id: <address@hidden>
---
kvm-all.c | 10 ++++++++--
target-i386/kvm.c | 24 ++++++++++++++++++++++++
target-mips/kvm.c | 4 ++++
target-ppc/kvm.c | 7 +++++++
target-s390x/kvm.c | 3 +++
5 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/kvm-all.c b/kvm-all.c
index e98b08d..ca428ca 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1755,6 +1755,8 @@ int kvm_cpu_exec(CPUState *cpu)
return EXCP_HLT;
}
+ qemu_mutex_unlock_iothread();
+
do {
MemTxAttrs attrs;
@@ -1773,11 +1775,9 @@ int kvm_cpu_exec(CPUState *cpu)
*/
qemu_cpu_kick_self();
}
- qemu_mutex_unlock_iothread();
run_ret = kvm_vcpu_ioctl(cpu, KVM_RUN, 0);
- qemu_mutex_lock_iothread();
attrs = kvm_arch_post_run(cpu, run);
if (run_ret < 0) {
@@ -1804,20 +1804,24 @@ int kvm_cpu_exec(CPUState *cpu)
switch (run->exit_reason) {
case KVM_EXIT_IO:
DPRINTF("handle_io\n");
+ qemu_mutex_lock_iothread();
kvm_handle_io(run->io.port, attrs,
(uint8_t *)run + run->io.data_offset,
run->io.direction,
run->io.size,
run->io.count);
+ qemu_mutex_unlock_iothread();
ret = 0;
break;
case KVM_EXIT_MMIO:
DPRINTF("handle_mmio\n");
+ qemu_mutex_lock_iothread();
address_space_rw(&address_space_memory,
run->mmio.phys_addr, attrs,
run->mmio.data,
run->mmio.len,
run->mmio.is_write);
+ qemu_mutex_unlock_iothread();
ret = 0;
break;
case KVM_EXIT_IRQ_WINDOW_OPEN:
@@ -1860,6 +1864,8 @@ int kvm_cpu_exec(CPUState *cpu)
}
} while (ret == 0);
+ qemu_mutex_lock_iothread();
+
if (ret < 0) {
cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_CODE);
vm_stop(RUN_STATE_INTERNAL_ERROR);
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index daced5c..6426600 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -2191,7 +2191,10 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)
/* Inject NMI */
if (cpu->interrupt_request & CPU_INTERRUPT_NMI) {
+ qemu_mutex_lock_iothread();
cpu->interrupt_request &= ~CPU_INTERRUPT_NMI;
+ qemu_mutex_unlock_iothread();
+
DPRINTF("injected NMI\n");
ret = kvm_vcpu_ioctl(cpu, KVM_NMI);
if (ret < 0) {
@@ -2200,6 +2203,10 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)
}
}
+ if (!kvm_irqchip_in_kernel()) {
+ qemu_mutex_lock_iothread();
+ }
+
/* Force the VCPU out of its inner loop to process any INIT requests
* or (for userspace APIC, but it is cheap to combine the checks here)
* pending TPR access reports.
@@ -2243,6 +2250,8 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)
DPRINTF("setting tpr\n");
run->cr8 = cpu_get_apic_tpr(x86_cpu->apic_state);
+
+ qemu_mutex_unlock_iothread();
}
}
@@ -2256,8 +2265,17 @@ MemTxAttrs kvm_arch_post_run(CPUState *cpu, struct
kvm_run *run)
} else {
env->eflags &= ~IF_MASK;
}
+
+ /* We need to protect the apic state against concurrent accesses from
+ * different threads in case the userspace irqchip is used. */
+ if (!kvm_irqchip_in_kernel()) {
+ qemu_mutex_lock_iothread();
+ }
cpu_set_apic_tpr(x86_cpu->apic_state, run->cr8);
cpu_set_apic_base(x86_cpu->apic_state, run->apic_base);
+ if (!kvm_irqchip_in_kernel()) {
+ qemu_mutex_unlock_iothread();
+ }
return cpu_get_mem_attrs(env);
}
@@ -2550,13 +2568,17 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
switch (run->exit_reason) {
case KVM_EXIT_HLT:
DPRINTF("handle_hlt\n");
+ qemu_mutex_lock_iothread();
ret = kvm_handle_halt(cpu);
+ qemu_mutex_unlock_iothread();
break;
case KVM_EXIT_SET_TPR:
ret = 0;
break;
case KVM_EXIT_TPR_ACCESS:
+ qemu_mutex_lock_iothread();
ret = kvm_handle_tpr_access(cpu);
+ qemu_mutex_unlock_iothread();
break;
case KVM_EXIT_FAIL_ENTRY:
code = run->fail_entry.hardware_entry_failure_reason;
@@ -2582,7 +2604,9 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
break;
case KVM_EXIT_DEBUG:
DPRINTF("kvm_exit_debug\n");
+ qemu_mutex_lock_iothread();
ret = kvm_handle_debug(cpu, &run->debug.arch);
+ qemu_mutex_unlock_iothread();
break;
default:
fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
diff --git a/target-mips/kvm.c b/target-mips/kvm.c
index 948619f..7d2293d 100644
--- a/target-mips/kvm.c
+++ b/target-mips/kvm.c
@@ -99,6 +99,8 @@ void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
int r;
struct kvm_mips_interrupt intr;
+ qemu_mutex_lock_iothread();
+
if ((cs->interrupt_request & CPU_INTERRUPT_HARD) &&
cpu_mips_io_interrupts_pending(cpu)) {
intr.cpu = -1;
@@ -109,6 +111,8 @@ void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
__func__, cs->cpu_index, intr.irq);
}
}
+
+ qemu_mutex_unlock_iothread();
}
MemTxAttrs kvm_arch_post_run(CPUState *cs, struct kvm_run *run)
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index afb4696..ddf469f 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1242,6 +1242,8 @@ void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
int r;
unsigned irq;
+ qemu_mutex_lock_iothread();
+
/* PowerPC QEMU tracks the various core input pins (interrupt, critical
* interrupt, reset, etc) in PPC-specific env->irq_input_state. */
if (!cap_interrupt_level &&
@@ -1269,6 +1271,8 @@ void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
/* We don't know if there are more interrupts pending after this. However,
* the guest will return to userspace in the course of handling this one
* anyways, so we will get a chance to deliver the rest. */
+
+ qemu_mutex_unlock_iothread();
}
MemTxAttrs kvm_arch_post_run(CPUState *cs, struct kvm_run *run)
@@ -1570,6 +1574,8 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
CPUPPCState *env = &cpu->env;
int ret;
+ qemu_mutex_lock_iothread();
+
switch (run->exit_reason) {
case KVM_EXIT_DCR:
if (run->dcr.is_write) {
@@ -1620,6 +1626,7 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
break;
}
+ qemu_mutex_unlock_iothread();
return ret;
}
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 135111a..ae3a0af 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -2007,6 +2007,8 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
S390CPU *cpu = S390_CPU(cs);
int ret = 0;
+ qemu_mutex_lock_iothread();
+
switch (run->exit_reason) {
case KVM_EXIT_S390_SIEIC:
ret = handle_intercept(cpu);
@@ -2027,6 +2029,7 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
fprintf(stderr, "Unknown KVM exit: %d\n", run->exit_reason);
break;
}
+ qemu_mutex_unlock_iothread();
if (ret == 0) {
ret = EXCP_INTERRUPT;
--
2.4.3
- [Qemu-devel] [PULL 07/19] cpu-defs: Move out TB_JMP defines, (continued)
- [Qemu-devel] [PULL 07/19] cpu-defs: Move out TB_JMP defines, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 03/19] memory_mapping: Rework cpu related includes, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 06/19] include/exec: Move tb hash functions out, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 08/19] Fix irq route entries exceeding KVM_MAX_IRQ_ROUTES, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 09/19] main-loop: use qemu_mutex_lock_iothread consistently, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 11/19] memory: Add global-locking property to memory regions, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 12/19] exec: pull qemu_flush_coalesced_mmio_buffer() into address_space_rw/ld*/st*, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 13/19] memory: let address_space_rw/ld*/st* run outside the BQL, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 10/19] main-loop: introduce qemu_mutex_iothread_locked, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 15/19] kvm: Switch to unlocked PIO, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 14/19] kvm: First step to push iothread lock out of inner run loop,
Paolo Bonzini <=
- [Qemu-devel] [PULL 16/19] acpi: mark PMTIMER as unlocked, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 19/19] exec: skip MMIO regions correctly in cpu_physical_memory_write_rom_internal, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 18/19] Stop including qemu-common.h in memory.h, Paolo Bonzini, 2015/07/06
- [Qemu-devel] [PULL 17/19] kvm: Switch to unlocked MMIO, Paolo Bonzini, 2015/07/06