Re: [PATCH 05/14] KVM: s390: Clear valid_wakeup in kvm_s390_handle_wait(), not in arch hook

From: Christian Borntraeger
Date: Mon Sep 27 2021 - 02:59:17 EST

Am 25.09.21 um 02:55 schrieb Sean Christopherson:
Move the clearing of valid_wakeup out of kvm_arch_vcpu_block_finish() so
that a future patch can drop said arch hook. Unlike the other blocking-
related arch hooks (vcpu_blocking/unblocking()), vcpu_block_finish() needs
to be called even if the KVM doesn't actually block the vCPU. This will
allow future patches to differentiate between truly blocking the vCPU and
emulating a halt condition without introducing a contradiction.

Alternatively, the hook could be renamed to kvm_arch_vcpu_halt_finish(),
but there's literally one call site in s390, and future cleanup can also
be done to handle valid_wakeup fully within kvm_s390_handle_wait() and
allow generic KVM to drop vcpu_valid_wakeup().

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>

Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
arch/s390/kvm/interrupt.c | 1 +
arch/s390/kvm/kvm-s390.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 10722455fd02..520450a7956f 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1336,6 +1336,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ vcpu->valid_wakeup = false;
vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 7cabe6778b1b..08ed68639a21 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -5082,7 +5082,7 @@ static inline unsigned long nonhyp_mask(int i)
void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu)
- vcpu->valid_wakeup = false;

maybe just remove the line instead of adding an empty one?

static int __init kvm_s390_init(void)