From: Cornelia Huck <cohuck@redhat.com>
To: Janosch Frank <frankja@linux.ibm.com>
Cc: thuth@redhat.com, david@redhat.com, qemu-devel@nongnu.org,
borntraeger@de.ibm.com, qemu-s390x@nongnu.org,
mihajlov@linux.ibm.com
Subject: Re: [PATCH v2 2/3] s390x: Add missing vcpu reset functions
Date: Mon, 2 Dec 2019 16:46:08 +0100 [thread overview]
Message-ID: <20191202164608.1b133a20.cohuck@redhat.com> (raw)
In-Reply-To: <20191202140146.3910-3-frankja@linux.ibm.com>
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/ ?
> 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?
> - 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?
> + }
> }
> }
>
(...)
> 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.
> + * 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 :)
> +}
> +
> +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);
next prev parent reply other threads:[~2019-12-02 15:48 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 ` Cornelia Huck [this message]
2019-12-03 13:03 ` [PATCH v2 2/3] " Janosch Frank
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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