From: Janosch Frank <frankja@linux.ibm.com>
To: qemu-devel@nongnu.org
Subject: Re: [PATCH v2 2/3] s390x: Add missing vcpu reset functions
Date: Tue, 3 Dec 2019 14:03:47 +0100 [thread overview]
Message-ID: <572646be-46cd-6c55-060f-314d042d015b@linux.ibm.com> (raw)
In-Reply-To: <20191202164608.1b133a20.cohuck@redhat.com>
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On 12/2/19 4:46 PM, Cornelia Huck wrote:
> On Mon, 2 Dec 2019 09:01:45 -0500
> Janosch Frank <frankja@linux.ibm.com> wrote:
>
>> Up to now we only had an ioctl to reset vcpu data QEMU couldn't reach
>> for the initial reset, which was also called for the clear reset. To
>
> s/which/and that/ ?
Ok
>
>> be architecture compliant, we also need to clear local interrupts on a
>> normal reset.
>>
>> Because of this and the upcoming protvirt support we need to add
>> ioctls for the missing clear and normal resets.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>> target/s390x/cpu.c | 14 ++++++++++++--
>> target/s390x/kvm-stub.c | 10 +++++++++-
>> target/s390x/kvm.c | 42 ++++++++++++++++++++++++++++++++--------
>> target/s390x/kvm_s390x.h | 4 +++-
>> 4 files changed, 58 insertions(+), 12 deletions(-)
>>
>> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
>> index 829ce6ad54..906285888e 100644
>> --- a/target/s390x/cpu.c
>> +++ b/target/s390x/cpu.c
>> @@ -139,8 +139,18 @@ static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
>> }
>>
>> /* Reset state inside the kernel that we cannot access yet from QEMU. */
>
> Hm, why does this comment talk about 'yet'? Did we have any plans to
> change that?
You're asking the wrong person :)
>
>> - if (kvm_enabled() && type != S390_CPU_RESET_NORMAL) {
>> - kvm_s390_reset_vcpu(cpu);
>> + if (kvm_enabled()) {
>> + switch (type) {
>> + case S390_CPU_RESET_CLEAR:
>> + kvm_s390_reset_vcpu_clear(cpu);
>> + break;
>> + case S390_CPU_RESET_INITIAL:
>> + kvm_s390_reset_vcpu_initial(cpu);
>> + break;
>> + case S390_CPU_RESET_NORMAL:
>> + kvm_s390_reset_vcpu_normal(cpu);
>> + break;
>
> Add a default case to catch errors?
Sure, just did
>
>> + }
>> }
>> }
>>
>
> (...)
>
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index ad6e38c876..7a2ec8b9f8 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -151,6 +151,7 @@ static int cap_s390_irq;
>> static int cap_ri;
>> static int cap_gs;
>> static int cap_hpage_1m;
>> +static int cap_vcpu_resets;
>>
>> static int active_cmma;
>>
>> @@ -342,6 +343,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>> cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
>> cap_mem_op = kvm_check_extension(s, KVM_CAP_S390_MEM_OP);
>> cap_s390_irq = kvm_check_extension(s, KVM_CAP_S390_INJECT_IRQ);
>> + cap_vcpu_resets = kvm_check_extension(s, KVM_CAP_S390_VCPU_RESETS);
>>
>> if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
>> || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
>> @@ -403,20 +405,44 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
>> return 0;
>> }
>>
>> -void kvm_s390_reset_vcpu(S390CPU *cpu)
>> +static void kvm_s390_reset_vcpu(S390CPU *cpu, unsigned long type)
>> {
>> CPUState *cs = CPU(cpu);
>>
>> - /* The initial reset call is needed here to reset in-kernel
>> - * vcpu data that we can't access directly from QEMU
>> - * (i.e. with older kernels which don't support sync_regs/ONE_REG).
>> - * Before this ioctl cpu_synchronize_state() is called in common kvm
>> - * code (kvm-all) */
>> - if (kvm_vcpu_ioctl(cs, KVM_S390_INITIAL_RESET, NULL)) {
>> - error_report("Initial CPU reset failed on CPU %i", cs->cpu_index);
>> + /*
>> + * The reset call is needed here to reset in-kernel vcpu data that
>> + * we can't access directly from QEMU (i.e. with older kernels
>> + * which don't support sync_regs/ONE_REG). Before this ioctl
>
> Is the reference to sync_regs/ONE_REG still relevant? I'm a bit
> confused here, especially with regard to what we'll need for protected
> virt.
I just didn't want to move/remove stuff
Even with kvm_run we do a lot of stuff for the initial reset.
>
>> + * cpu_synchronize_state() is called in common kvm code
>> + * (kvm-all).
>> + */
>> + if (kvm_vcpu_ioctl(cs, type)) {
>> + error_report("CPU reset failed on CPU %i", cs->cpu_index);
>> }
>> }
>>
>> +void kvm_s390_reset_vcpu_initial(S390CPU *cpu)
>> +{
>> + kvm_s390_reset_vcpu(cpu, KVM_S390_INITIAL_RESET);
>> +}
>> +
>> +void kvm_s390_reset_vcpu_clear(S390CPU *cpu)
>> +{
>> + if (!cap_vcpu_resets) {
>> + kvm_s390_reset_vcpu(cpu, KVM_S390_INITIAL_RESET);
>> + } else {
>> + kvm_s390_reset_vcpu(cpu, KVM_S390_CLEAR_RESET);
>> + }
>
> kvm_s390_reset_vcpu(cpu, cap_vcpu_resets ? KVM_S390_CLEAR_RESET : KVM_S390_INITIAL_RESET);
>
> One line, but maybe the conventional if is still better :)
I'd like to keep it as is.
>
>> +}
>> +
>> +void kvm_s390_reset_vcpu_normal(S390CPU *cpu)
>> +{
>> + if (!cap_vcpu_resets) {
>> + return;
>> + }
>> + kvm_s390_reset_vcpu(cpu, KVM_S390_NORMAL_RESET);
>> +}
>> +
>> static int can_sync_regs(CPUState *cs, int regs)
>> {
>> return cap_sync_regs && (cs->kvm_run->kvm_valid_regs & regs) == regs;
>> diff --git a/target/s390x/kvm_s390x.h b/target/s390x/kvm_s390x.h
>> index caf985955b..0b21789796 100644
>> --- a/target/s390x/kvm_s390x.h
>> +++ b/target/s390x/kvm_s390x.h
>> @@ -34,7 +34,9 @@ int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
>> int vq, bool assign);
>> int kvm_s390_cmma_active(void);
>> void kvm_s390_cmma_reset(void);
>> -void kvm_s390_reset_vcpu(S390CPU *cpu);
>> +void kvm_s390_reset_vcpu_clear(S390CPU *cpu);
>> +void kvm_s390_reset_vcpu_normal(S390CPU *cpu);
>> +void kvm_s390_reset_vcpu_initial(S390CPU *cpu);
>> int kvm_s390_set_mem_limit(uint64_t new_limit, uint64_t *hw_limit);
>> void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp);
>> void kvm_s390_crypto_reset(void);
>
>
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next prev parent reply other threads:[~2019-12-03 13:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-02 14:01 [PATCH v2 0/3] s390x: Increase architectural compliance Janosch Frank
2019-12-02 14:01 ` [PATCH v2 1/3] Header sync Janosch Frank
2019-12-02 14:01 ` [PATCH v2 2/3] s390x: Add missing vcpu reset functions Janosch Frank
2019-12-02 14:22 ` David Hildenbrand
2019-12-02 14:28 ` Thomas Huth
2019-12-02 14:48 ` [PATCH v3] " Janosch Frank
2019-12-02 15:46 ` [PATCH v2 2/3] " Cornelia Huck
2019-12-03 13:03 ` Janosch Frank [this message]
2019-12-02 14:01 ` [PATCH v2 3/3] s390x: Fix cpu normal reset ri clearing Janosch Frank
2019-12-03 10:07 ` Christian Borntraeger
2019-12-03 10:21 ` David Hildenbrand
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