Re: [PATCH 15/21] qemu-kvm: Clean up mpstate synchronization

Jan Kiszka
2010-02-02T12:40:53Z

Gleb Natapov wrote:
> On Tue, Feb 02, 2010 at 01:31:50PM +0100, Jan Kiszka wrote:
>> Gleb Natapov wrote:
>>> On Tue, Feb 02, 2010 at 09:19:01AM +0100, Jan Kiszka wrote:
>>>> Push mpstate reading/writing into kvm_arch_load/save_regs and, on x86,
>>>> properly synchronize with halted in the accessor functions.
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>> ---
>>>> hw/apic.c | 7 ----
>>>> qemu-kvm-ia64.c | 4 ++-
>>>> qemu-kvm-x86.c | 88 +++++++++++++++++++++++++++---------------------
>>>> qemu-kvm.c | 30 -----------------
>>>> qemu-kvm.h | 15 --------
>>>> target-i386/machine.c | 6 ---
>>>> target-ia64/machine.c | 3 ++
>>>> 7 files changed, 55 insertions(+), 98 deletions(-)
>>>>
>>>> diff --git a/hw/apic.c b/hw/apic.c
>>>> index 3e03e10..092c61e 100644
>>>> --- a/hw/apic.c
>>>> +++ b/hw/apic.c
>>>> @@ -507,13 +507,6 @@ void apic_init_reset(CPUState *env)
>>>> s->wait_for_sipi = 1;
>>>>
>>>> env->halted = !(s->apicbase & MSR_IA32_APICBASE_BSP);
>>>> -#ifdef KVM_CAP_MP_STATE
>>>> - if (kvm_enabled() && kvm_irqchip_in_kernel()) {
>>>> - env->mp_state
>>>> - = env->halted ? KVM_MP_STATE_UNINITIALIZED : KVM_MP_STATE_RUNNABLE;
>>>> - kvm_load_mpstate(env);
>>>> - }
>>>> -#endif
>>>> }
>>>>
>>>> static void apic_startup(APICState *s, int vector_num)
>>>> diff --git a/qemu-kvm-ia64.c b/qemu-kvm-ia64.c
>>>> index fc8110e..39bcbeb 100644
>>>> --- a/qemu-kvm-ia64.c
>>>> +++ b/qemu-kvm-ia64.c
>>>> @@ -124,7 +124,9 @@ void kvm_arch_cpu_reset(CPUState *env)
>>>> {
>>>> if (kvm_irqchip_in_kernel(kvm_context)) {
>>>> #ifdef KVM_CAP_MP_STATE
>>>> - kvm_reset_mpstate(env->kvm_cpu_state.vcpu_ctx);
>>>> + struct kvm_mp_state mp_state = {.mp_state = KVM_MP_STATE_UNINITIALIZED
>>>> + };
>>>> + kvm_set_mpstate(env, &mp_state);
>>>> #endif
>>>> } else {
>>>> env->interrupt_request &= ~CPU_INTERRUPT_HARD;
>>>> diff --git a/qemu-kvm-x86.c b/qemu-kvm-x86.c
>>>> index 63cd095..6b5895f 100644
>>>> --- a/qemu-kvm-x86.c
>>>> +++ b/qemu-kvm-x86.c
>>>> @@ -754,6 +754,48 @@ static int get_msr_entry(struct kvm_msr_entry *entry, CPUState *env)
>>>> return 0;
>>>> }
>>>>
>>>> +static void kvm_arch_save_mpstate(CPUState *env)
>>>> +{
>>>> +#ifdef KVM_CAP_MP_STATE
>>>> + int r;
>>>> + struct kvm_mp_state mp_state;
>>>> +
>>>> + r = kvm_get_mpstate(env, &mp_state);
>>>> + if (r < 0) {
>>>> + env->mp_state = -1;
>>>> + } else {
>>>> + env->mp_state = mp_state.mp_state;
>>>> + if (kvm_irqchip_in_kernel()) {
>>>> + env->halted = (env->mp_state == KVM_MP_STATE_HALTED);
>>>> + }
>>>> + }
>>>> +#else
>>>> + env->mp_state = -1;
>>>> +#endif
>>>> +}
>>>> +
>>>> +static void kvm_arch_load_mpstate(CPUState *env)
>>>> +{
>>>> +#ifdef KVM_CAP_MP_STATE
>>>> + struct kvm_mp_state mp_state;
>>>> +
>>>> + /*
>>>> + * -1 indicates that the host did not support GET_MP_STATE ioctl,
>>>> + * so don't touch it.
>>>> + */
>>>> + if (env->mp_state != -1) {
>>>> + if (kvm_irqchip_in_kernel()) {
>>>> + env->mp_state = env->halted ? KVM_MP_STATE_UNINITIALIZED :
>>>> + KVM_MP_STATE_RUNNABLE;
>>> When irqchip is in kernel env->halted doesn't contain any relevant
>>> information, so this is incorrect. Actually env->halted is updated only
>>> to show correct cpu state during "info cpus".
>> OK, copied from apic_init_reset, see above. So that hunk was probably at
>> least useless, and now it's harmfull. Will drop this and only sync from
>> mp_state -> halted.
>>
> It was not useless in apic_init_reset it was a shortcut for:
> env->mp_state = !(s->apicbase & MSR_IA32_APICBASE_BSP) ? KVM_MP_STATE_UNINITIALIZED : KVM_MP_STATE_RUNNABLE;
>
> On reset BSP VCPU should set env->mp_state to KVM_MP_STATE_RUNNABLE and
> all others to KVM_MP_STATE_UNINITIALIZED.

OK, belongs to kvm vpcu init code then - less encrypted.

Jan

--
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