6.6-stable review patch. If anyone has any objections, please let me know.
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From: Yong-Xuan Wang yongxuan.wang@sifive.com
[ Upstream commit 2121cadec45aaf61fa45b3aa3d99723ed4e6683a ]
Documentation/virt/kvm/locking.rst advises that kvm->lock should be acquired outside vcpu->mutex and kvm->srcu. However, when KVM/RISC-V handling SBI_EXT_HSM_HART_START, the lock ordering is vcpu->mutex, kvm->srcu then kvm->lock.
Although the lockdep checking no longer complains about this after commit f0f44752f5f6 ("rcu: Annotate SRCU's update-side lockdep dependencies"), it's necessary to replace kvm->lock with a new dedicated lock to ensure only one hart can execute the SBI_EXT_HSM_HART_START call for the target hart simultaneously.
Additionally, this patch also rename "power_off" to "mp_state" with two possible values. The vcpu->mp_state_lock also protects the access of vcpu->mp_state.
Signed-off-by: Yong-Xuan Wang yongxuan.wang@sifive.com Reviewed-by: Anup Patel anup@brainfault.org Link: https://lore.kernel.org/r/20240417074528.16506-2-yongxuan.wang@sifive.com Signed-off-by: Anup Patel anup@brainfault.org Stable-dep-of: c7db342e3b47 ("riscv: KVM: Fix hart suspend status check") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/kvm_host.h | 8 ++++-- arch/riscv/kvm/vcpu.c | 48 ++++++++++++++++++++++--------- arch/riscv/kvm/vcpu_sbi.c | 7 +++-- arch/riscv/kvm/vcpu_sbi_hsm.c | 39 +++++++++++++++++-------- 4 files changed, 73 insertions(+), 29 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 1ebf20dfbaa69..459e61ad7d2b6 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -236,8 +236,9 @@ struct kvm_vcpu_arch { /* Cache pages needed to program page tables with spinlock held */ struct kvm_mmu_memory_cache mmu_page_cache;
- /* VCPU power-off state */ - bool power_off; + /* VCPU power state */ + struct kvm_mp_state mp_state; + spinlock_t mp_state_lock;
/* Don't run the VCPU (blocked) */ bool pause; @@ -351,7 +352,10 @@ int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq); void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu); bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask); +void __kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu); +void __kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu); +bool kvm_riscv_vcpu_stopped(struct kvm_vcpu *vcpu);
#endif /* __RISCV_KVM_HOST_H__ */ diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 82229db1ce73f..9584d62c96ee7 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -100,6 +100,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) struct kvm_cpu_context *cntx; struct kvm_vcpu_csr *reset_csr = &vcpu->arch.guest_reset_csr;
+ spin_lock_init(&vcpu->arch.mp_state_lock); + /* Mark this VCPU never ran */ vcpu->arch.ran_atleast_once = false; vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; @@ -193,7 +195,7 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) { return (kvm_riscv_vcpu_has_interrupts(vcpu, -1UL) && - !vcpu->arch.power_off && !vcpu->arch.pause); + !kvm_riscv_vcpu_stopped(vcpu) && !vcpu->arch.pause); }
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) @@ -421,26 +423,42 @@ bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) return kvm_riscv_vcpu_aia_has_interrupts(vcpu, mask); }
-void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu) +void __kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu) { - vcpu->arch.power_off = true; + WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED); kvm_make_request(KVM_REQ_SLEEP, vcpu); kvm_vcpu_kick(vcpu); }
-void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu) +void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu) { - vcpu->arch.power_off = false; + spin_lock(&vcpu->arch.mp_state_lock); + __kvm_riscv_vcpu_power_off(vcpu); + spin_unlock(&vcpu->arch.mp_state_lock); +} + +void __kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu) +{ + WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE); kvm_vcpu_wake_up(vcpu); }
+void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu) +{ + spin_lock(&vcpu->arch.mp_state_lock); + __kvm_riscv_vcpu_power_on(vcpu); + spin_unlock(&vcpu->arch.mp_state_lock); +} + +bool kvm_riscv_vcpu_stopped(struct kvm_vcpu *vcpu) +{ + return READ_ONCE(vcpu->arch.mp_state.mp_state) == KVM_MP_STATE_STOPPED; +} + int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu, struct kvm_mp_state *mp_state) { - if (vcpu->arch.power_off) - mp_state->mp_state = KVM_MP_STATE_STOPPED; - else - mp_state->mp_state = KVM_MP_STATE_RUNNABLE; + *mp_state = READ_ONCE(vcpu->arch.mp_state);
return 0; } @@ -450,17 +468,21 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, { int ret = 0;
+ spin_lock(&vcpu->arch.mp_state_lock); + switch (mp_state->mp_state) { case KVM_MP_STATE_RUNNABLE: - vcpu->arch.power_off = false; + WRITE_ONCE(vcpu->arch.mp_state, *mp_state); break; case KVM_MP_STATE_STOPPED: - kvm_riscv_vcpu_power_off(vcpu); + __kvm_riscv_vcpu_power_off(vcpu); break; default: ret = -EINVAL; }
+ spin_unlock(&vcpu->arch.mp_state_lock); + return ret; }
@@ -561,11 +583,11 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu) if (kvm_check_request(KVM_REQ_SLEEP, vcpu)) { kvm_vcpu_srcu_read_unlock(vcpu); rcuwait_wait_event(wait, - (!vcpu->arch.power_off) && (!vcpu->arch.pause), + (!kvm_riscv_vcpu_stopped(vcpu)) && (!vcpu->arch.pause), TASK_INTERRUPTIBLE); kvm_vcpu_srcu_read_lock(vcpu);
- if (vcpu->arch.power_off || vcpu->arch.pause) { + if (kvm_riscv_vcpu_stopped(vcpu) || vcpu->arch.pause) { /* * Awaken to handle a signal, request to * sleep again later. diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 7a7fe40d0930b..be43278109f4e 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -102,8 +102,11 @@ void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu, unsigned long i; struct kvm_vcpu *tmp;
- kvm_for_each_vcpu(i, tmp, vcpu->kvm) - tmp->arch.power_off = true; + kvm_for_each_vcpu(i, tmp, vcpu->kvm) { + spin_lock(&vcpu->arch.mp_state_lock); + WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED); + spin_unlock(&vcpu->arch.mp_state_lock); + } kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
memset(&run->system_event, 0, sizeof(run->system_event)); diff --git a/arch/riscv/kvm/vcpu_sbi_hsm.c b/arch/riscv/kvm/vcpu_sbi_hsm.c index 7dca0e9381d9a..827d946ab8714 100644 --- a/arch/riscv/kvm/vcpu_sbi_hsm.c +++ b/arch/riscv/kvm/vcpu_sbi_hsm.c @@ -18,12 +18,18 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) struct kvm_cpu_context *cp = &vcpu->arch.guest_context; struct kvm_vcpu *target_vcpu; unsigned long target_vcpuid = cp->a0; + int ret = 0;
target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid); if (!target_vcpu) return SBI_ERR_INVALID_PARAM; - if (!target_vcpu->arch.power_off) - return SBI_ERR_ALREADY_AVAILABLE; + + spin_lock(&target_vcpu->arch.mp_state_lock); + + if (!kvm_riscv_vcpu_stopped(target_vcpu)) { + ret = SBI_ERR_ALREADY_AVAILABLE; + goto out; + }
reset_cntx = &target_vcpu->arch.guest_reset_context; /* start address */ @@ -34,19 +40,31 @@ static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu) reset_cntx->a1 = cp->a2; kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu);
- kvm_riscv_vcpu_power_on(target_vcpu); + __kvm_riscv_vcpu_power_on(target_vcpu);
- return 0; +out: + spin_unlock(&target_vcpu->arch.mp_state_lock); + + return ret; }
static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu) { - if (vcpu->arch.power_off) - return SBI_ERR_FAILURE; + int ret = 0;
- kvm_riscv_vcpu_power_off(vcpu); + spin_lock(&vcpu->arch.mp_state_lock);
- return 0; + if (kvm_riscv_vcpu_stopped(vcpu)) { + ret = SBI_ERR_FAILURE; + goto out; + } + + __kvm_riscv_vcpu_power_off(vcpu); + +out: + spin_unlock(&vcpu->arch.mp_state_lock); + + return ret; }
static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu) @@ -58,7 +76,7 @@ static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu) target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid); if (!target_vcpu) return SBI_ERR_INVALID_PARAM; - if (!target_vcpu->arch.power_off) + if (!kvm_riscv_vcpu_stopped(target_vcpu)) return SBI_HSM_STATE_STARTED; else if (vcpu->stat.generic.blocking) return SBI_HSM_STATE_SUSPENDED; @@ -71,14 +89,11 @@ static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run, { int ret = 0; struct kvm_cpu_context *cp = &vcpu->arch.guest_context; - struct kvm *kvm = vcpu->kvm; unsigned long funcid = cp->a6;
switch (funcid) { case SBI_EXT_HSM_HART_START: - mutex_lock(&kvm->lock); ret = kvm_sbi_hsm_vcpu_start(vcpu); - mutex_unlock(&kvm->lock); break; case SBI_EXT_HSM_HART_STOP: ret = kvm_sbi_hsm_vcpu_stop(vcpu);