| Message ID | CAAhSdy1CAtr=mAVFtduTcED_Sjp2=4duQwgL5syxZ-sYM6SoWQ@mail.gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [GIT,PULL] KVM/riscv fixes for 5.19, take #2 | expand |
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. Also, I only had a quick look but it seems like vcpu->arch.pause is never written? Paolo
On Wed, Jul 13, 2022 at 11:30 AM Paolo Bonzini <pbonzini@redhat.com> 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. 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
On 7/13/22 09:17, Anup Patel wrote: > On Wed, Jul 13, 2022 at 11:30 AM Paolo Bonzini <pbonzini@redhat.com> 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 >
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() Please pull. Regards, Anup The following changes since commit 32346491ddf24599decca06190ebca03ff9de7f8: Linux 5.19-rc6 (2022-07-10 14:40:51 -0700) are available in the Git repository at: https://github.com/kvm-riscv/linux.git tags/kvm-riscv-fixes-5.19-2 for you to fetch changes up to be82abe6a76ba8e76f25312566182b0f13c4fbf9: RISC-V: KVM: Fix SRCU deadlock caused by kvm_riscv_check_vcpu_requests() (2022-07-11 09:36:32 +0530) ---------------------------------------------------------------- KVM/riscv fixes for 5.19, take #2 - Fix missing PAGE_PFN_MASK - Fix SRCU deadlock caused by kvm_riscv_check_vcpu_requests() ---------------------------------------------------------------- Alexandre Ghiti (1): riscv: Fix missing PAGE_PFN_MASK Anup Patel (1): RISC-V: KVM: Fix SRCU deadlock caused by kvm_riscv_check_vcpu_requests() arch/riscv/include/asm/pgtable-64.h | 12 ++++++------ arch/riscv/include/asm/pgtable.h | 6 +++--- arch/riscv/kvm/mmu.c | 2 +- arch/riscv/kvm/vcpu.c | 2 ++ 4 files changed, 12 insertions(+), 10 deletions(-)