| title: | PATCH v3 05 10 KVM x86 Restrict writeback |
|
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 <jan.kiszka@xxxxxxxxxxx
---
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 3ec5b59..3ee307d 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 4e6ae70..b0f9670 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);
if (!cpu_is_bsp(env) && !kvm_irqchip_in_kernel()) {
env- interrupt_request &= ~CPU_INTERRUPT_HARD;
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 5f0829b..f1f44d3 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -541,7 +541,7 @@ 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;
@@ -555,7 +555,6 @@ 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 */
@@ -564,8 +563,12 @@ 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;
@@ -783,7 +786,7 @@ 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;
@@ -807,8 +810,11 @@ 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
@@ -901,15 +907,17 @@ 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
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