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[Qemu-devel] [PATCH v4 05/10] KVM: x86: Restrict writeback of VCPU state
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH v4 05/10] KVM: x86: Restrict writeback of VCPU state |
Date: |
Mon, 1 Mar 2010 18:17:24 +0100 |
Do not write nmi_pending, sipi_vector, and mpstate unless we at least go
through a reset. And TSC as well as KVM wallclocks should only be
written on full sync, otherwise we risk to drop some time on during
state read-modify-write.
Signed-off-by: Jan Kiszka <address@hidden>
---
kvm.h | 2 +-
qemu-kvm-x86.c | 2 +-
target-i386/kvm.c | 32 ++++++++++++++++++++------------
target-i386/machine.c | 2 +-
4 files changed, 23 insertions(+), 15 deletions(-)
diff --git a/kvm.h b/kvm.h
index 874506b..afc7ee0 100644
--- a/kvm.h
+++ b/kvm.h
@@ -44,7 +44,7 @@ int kvm_log_stop(target_phys_addr_t phys_addr, ram_addr_t
size);
int kvm_has_sync_mmu(void);
int kvm_has_vcpu_events(void);
int kvm_has_robust_singlestep(void);
-int kvm_put_vcpu_events(CPUState *env);
+int kvm_put_vcpu_events(CPUState *env, int level);
int kvm_get_vcpu_events(CPUState *env);
void kvm_cpu_register_phys_memory_client(void);
diff --git a/qemu-kvm-x86.c b/qemu-kvm-x86.c
index 61b3dde..d1a8f3b 100644
--- a/qemu-kvm-x86.c
+++ b/qemu-kvm-x86.c
@@ -1391,7 +1391,7 @@ void kvm_arch_push_nmi(void *opaque)
void kvm_arch_cpu_reset(CPUState *env)
{
kvm_arch_reset_vcpu(env);
- kvm_put_vcpu_events(env);
+ kvm_put_vcpu_events(env, KVM_PUT_RESET_STATE);
kvm_reset_mpstate(env);
}
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 23729ef..377829c 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -549,7 +549,7 @@ static void kvm_msr_entry_set(struct kvm_msr_entry *entry,
entry->data = value;
}
-static int kvm_put_msrs(CPUState *env)
+static int kvm_put_msrs(CPUState *env, int level)
{
struct {
struct kvm_msrs info;
@@ -563,7 +563,6 @@ static int kvm_put_msrs(CPUState *env)
kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_EIP, env->sysenter_eip);
if (kvm_has_msr_star(env))
kvm_msr_entry_set(&msrs[n++], MSR_STAR, env->star);
- kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
kvm_msr_entry_set(&msrs[n++], MSR_VM_HSAVE_PA, env->vm_hsave);
#ifdef TARGET_X86_64
/* FIXME if lm capable */
@@ -572,8 +571,12 @@ static int kvm_put_msrs(CPUState *env)
kvm_msr_entry_set(&msrs[n++], MSR_FMASK, env->fmask);
kvm_msr_entry_set(&msrs[n++], MSR_LSTAR, env->lstar);
#endif
- kvm_msr_entry_set(&msrs[n++], MSR_KVM_SYSTEM_TIME, env->system_time_msr);
- kvm_msr_entry_set(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
+ if (level == KVM_PUT_FULL_STATE) {
+ kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
+ kvm_msr_entry_set(&msrs[n++], MSR_KVM_SYSTEM_TIME,
+ env->system_time_msr);
+ kvm_msr_entry_set(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
+ }
msr_data.info.nmsrs = n;
@@ -791,7 +794,7 @@ static int kvm_get_mp_state(CPUState *env)
}
#endif
-int kvm_put_vcpu_events(CPUState *env)
+int kvm_put_vcpu_events(CPUState *env, int level)
{
#ifdef KVM_CAP_VCPU_EVENTS
struct kvm_vcpu_events events;
@@ -815,8 +818,11 @@ int kvm_put_vcpu_events(CPUState *env)
events.sipi_vector = env->sipi_vector;
- events.flags =
- KVM_VCPUEVENT_VALID_NMI_PENDING | KVM_VCPUEVENT_VALID_SIPI_VECTOR;
+ events.flags = 0;
+ if (level >= KVM_PUT_RESET_STATE) {
+ events.flags |=
+ KVM_VCPUEVENT_VALID_NMI_PENDING | KVM_VCPUEVENT_VALID_SIPI_VECTOR;
+ }
return kvm_vcpu_ioctl(env, KVM_SET_VCPU_EVENTS, &events);
#else
@@ -909,15 +915,17 @@ int kvm_arch_put_registers(CPUState *env, int level)
if (ret < 0)
return ret;
- ret = kvm_put_msrs(env);
+ ret = kvm_put_msrs(env, level);
if (ret < 0)
return ret;
- ret = kvm_put_mp_state(env);
- if (ret < 0)
- return ret;
+ if (level >= KVM_PUT_RESET_STATE) {
+ ret = kvm_put_mp_state(env);
+ if (ret < 0)
+ return ret;
+ }
- ret = kvm_put_vcpu_events(env);
+ ret = kvm_put_vcpu_events(env, level);
if (ret < 0)
return ret;
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 61e6a87..6fca559 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -362,7 +362,7 @@ static int cpu_post_load(void *opaque, int version_id)
if (kvm_enabled()) {
kvm_load_tsc(env);
- kvm_put_vcpu_events(env);
+ kvm_put_vcpu_events(env, KVM_PUT_FULL_STATE);
}
return 0;
--
1.6.0.2
- [Qemu-devel] [PATCH v4 00/10] qemu-kvm: Hook cleanups and yet more use of upstream code, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 09/10] qemu-kvm: Move kvm_set_boot_cpu_id, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 05/10] KVM: x86: Restrict writeback of VCPU state,
Jan Kiszka <=
- [Qemu-devel] [PATCH v4 04/10] qemu-kvm: Clean up mpstate synchronization, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 08/10] qemu-kvm: Clean up KVM's APIC hooks, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 02/10] qemu-kvm: Rework VCPU state writeback API, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 06/10] qemu-kvm: Use VCPU event state for reset and vmsave/load, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 01/10] qemu-kvm: Add KVM_CAP_X86_ROBUST_SINGLESTEP-awareness, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 07/10] qemu-kvm: Cleanup/fix TSC and PV clock writeback, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 10/10] qemu-kvm: Bring qemu_init_vcpu back home, Jan Kiszka, 2010/03/01
- [Qemu-devel] [PATCH v4 03/10] x86: Extend validity of cpu_is_bsp, Jan Kiszka, 2010/03/01