| Message ID | 20240417074528.16506-3-yongxuan.wang@sifive.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | RISCV: KVM: Avoid lock inversion in SBI_EXT_HSM_HART_START | expand |
On Wed, Apr 17, 2024 at 1:15 PM Yong-Xuan Wang <yongxuan.wang@sifive.com> wrote: > > Originally, the use of kvm->lock in SBI_EXT_HSM_HART_START also avoids > the simultaneous updates to the reset context of target VCPU. Since this > lock has been replace with vcpu->mp_state_lock, and this new lock also > protects the vcpu->mp_state. We have to add a separate lock for > vcpu->reset_cntx. > > Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> LGTM. Reviewed-by: Anup Patel <anup@brainfault.org> Regards, Anup > --- > arch/riscv/include/asm/kvm_host.h | 1 + > arch/riscv/kvm/vcpu.c | 6 ++++++ > arch/riscv/kvm/vcpu_sbi_hsm.c | 3 +++ > 3 files changed, 10 insertions(+) > > diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h > index 64d35a8c908c..664d1bb00368 100644 > --- a/arch/riscv/include/asm/kvm_host.h > +++ b/arch/riscv/include/asm/kvm_host.h > @@ -211,6 +211,7 @@ struct kvm_vcpu_arch { > > /* CPU context upon Guest VCPU reset */ > struct kvm_cpu_context guest_reset_context; > + spinlock_t reset_cntx_lock; > > /* CPU CSR context upon Guest VCPU reset */ > struct kvm_vcpu_csr guest_reset_csr; > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > index 70937f71c3c4..1a2236e4c7f3 100644 > --- a/arch/riscv/kvm/vcpu.c > +++ b/arch/riscv/kvm/vcpu.c > @@ -64,7 +64,9 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu) > > memcpy(csr, reset_csr, sizeof(*csr)); > > + spin_lock(&vcpu->arch.reset_cntx_lock); > memcpy(cntx, reset_cntx, sizeof(*cntx)); > + spin_unlock(&vcpu->arch.reset_cntx_lock); > > kvm_riscv_vcpu_fp_reset(vcpu); > > @@ -121,12 +123,16 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) > spin_lock_init(&vcpu->arch.hfence_lock); > > /* Setup reset state of shadow SSTATUS and HSTATUS CSRs */ > + spin_lock_init(&vcpu->arch.reset_cntx_lock); > + > + spin_lock(&vcpu->arch.reset_cntx_lock); > cntx = &vcpu->arch.guest_reset_context; > cntx->sstatus = SR_SPP | SR_SPIE; > cntx->hstatus = 0; > cntx->hstatus |= HSTATUS_VTW; > cntx->hstatus |= HSTATUS_SPVP; > cntx->hstatus |= HSTATUS_SPV; > + spin_unlock(&vcpu->arch.reset_cntx_lock); > > if (kvm_riscv_vcpu_alloc_vector_context(vcpu, cntx)) > return -ENOMEM; > diff --git a/arch/riscv/kvm/vcpu_sbi_hsm.c b/arch/riscv/kvm/vcpu_sbi_hsm.c > index 115a6c6525fd..cc5038b90e02 100644 > --- a/arch/riscv/kvm/vcpu_sbi_hsm.c > +++ b/arch/riscv/kvm/vcpu_sbi_hsm.c > @@ -31,6 +31,7 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) > goto out; > } > > + spin_lock(&target_vcpu->arch.reset_cntx_lock); > reset_cntx = &target_vcpu->arch.guest_reset_context; > /* start address */ > reset_cntx->sepc = cp->a1; > @@ -38,6 +39,8 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) > reset_cntx->a0 = target_vcpuid; > /* private data passed from kernel */ > reset_cntx->a1 = cp->a2; > + spin_unlock(&target_vcpu->arch.reset_cntx_lock); > + > kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu); > > __kvm_riscv_vcpu_power_on(target_vcpu); > -- > 2.17.1 >
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 64d35a8c908c..664d1bb00368 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -211,6 +211,7 @@ struct kvm_vcpu_arch { /* CPU context upon Guest VCPU reset */ struct kvm_cpu_context guest_reset_context; + spinlock_t reset_cntx_lock; /* CPU CSR context upon Guest VCPU reset */ struct kvm_vcpu_csr guest_reset_csr; diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 70937f71c3c4..1a2236e4c7f3 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -64,7 +64,9 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu) memcpy(csr, reset_csr, sizeof(*csr)); + spin_lock(&vcpu->arch.reset_cntx_lock); memcpy(cntx, reset_cntx, sizeof(*cntx)); + spin_unlock(&vcpu->arch.reset_cntx_lock); kvm_riscv_vcpu_fp_reset(vcpu); @@ -121,12 +123,16 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) spin_lock_init(&vcpu->arch.hfence_lock); /* Setup reset state of shadow SSTATUS and HSTATUS CSRs */ + spin_lock_init(&vcpu->arch.reset_cntx_lock); + + spin_lock(&vcpu->arch.reset_cntx_lock); cntx = &vcpu->arch.guest_reset_context; cntx->sstatus = SR_SPP | SR_SPIE; cntx->hstatus = 0; cntx->hstatus |= HSTATUS_VTW; cntx->hstatus |= HSTATUS_SPVP; cntx->hstatus |= HSTATUS_SPV; + spin_unlock(&vcpu->arch.reset_cntx_lock); if (kvm_riscv_vcpu_alloc_vector_context(vcpu, cntx)) return -ENOMEM; diff --git a/arch/riscv/kvm/vcpu_sbi_hsm.c b/arch/riscv/kvm/vcpu_sbi_hsm.c index 115a6c6525fd..cc5038b90e02 100644 --- a/arch/riscv/kvm/vcpu_sbi_hsm.c +++ b/arch/riscv/kvm/vcpu_sbi_hsm.c @@ -31,6 +31,7 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) goto out; } + spin_lock(&target_vcpu->arch.reset_cntx_lock); reset_cntx = &target_vcpu->arch.guest_reset_context; /* start address */ reset_cntx->sepc = cp->a1; @@ -38,6 +39,8 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) reset_cntx->a0 = target_vcpuid; /* private data passed from kernel */ reset_cntx->a1 = cp->a2; + spin_unlock(&target_vcpu->arch.reset_cntx_lock); + kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu); __kvm_riscv_vcpu_power_on(target_vcpu);
Originally, the use of kvm->lock in SBI_EXT_HSM_HART_START also avoids the simultaneous updates to the reset context of target VCPU. Since this lock has been replace with vcpu->mp_state_lock, and this new lock also protects the vcpu->mp_state. We have to add a separate lock for vcpu->reset_cntx. Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> --- arch/riscv/include/asm/kvm_host.h | 1 + arch/riscv/kvm/vcpu.c | 6 ++++++ arch/riscv/kvm/vcpu_sbi_hsm.c | 3 +++ 3 files changed, 10 insertions(+)