On 7/13/22 09:17, Anup Patel wrote:
On Wed, Jul 13, 2022 at 11:30 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
On 7/13/22 07:47, Anup Patel wrote:
Hi Paolo,
We have two more fixes for 5.19 which were discovered recently:
1) Fix missing PAGE_PFN_MASK
2) Fix SRCU deadlock caused by kvm_riscv_check_vcpu_requests()
Pulled, thanks.
For the latter, my suggestion is to remove KVM_REQ_SLEEP completely and
key the waiting on kvm_arch_vcpu_runnable using kvm_vcpu_halt or
kvm_vcpu_block.
We are using KVM_REQ_SLEEP for VCPU hotplug. The secondary
VCPUs will block until woken-up by using an SBI call from other VCPU.
This is different from blocking on WFI where VCPU will wake-up upon
any interrupt.
Yes, I understand. The idea is to have something like
if (kvm_arch_vcpu_runnable())
vcpu_enter_guest(vcpu);
else
kvm_vcpu_block(vcpu);
instead of using KVM_REQ_SLEEP to enter the blocking loop. This works
for both WFI and hotplug, the only difference between the two cases is
the event that changes kvm_arch_vcpu_runnable() to true.
Paolo
I agree with your suggestion, we should definitely use kvm_vcpu_block()
here.
Also, I only had a quick look but it seems like vcpu->arch.pause is
never written?
Yes, the vcpu->arch.pause is redundant. I will remove it.
Paolo
Thanks,
Anup
