From 6d3cfbe21bef5b66530b50ad16c88fdc71a04c35 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 4 Dec 2014 15:02:24 +0000 Subject: arm/arm64: KVM: vgic: move reset initialization into vgic_init_maps() VGIC initialization currently happens in three phases: (1) kvm_vgic_create() (triggered by userspace GIC creation) (2) vgic_init_maps() (triggered by userspace GIC register read/write requests, or from kvm_vgic_init() if not already run) (3) kvm_vgic_init() (triggered by first VM run) We were doing initialization of some state to correspond with the state of a freshly-reset GIC in kvm_vgic_init(); this is too late, since it will overwrite changes made by userspace using the register access APIs before the VM is run. Move this initialization earlier, into the vgic_init_maps() phase. This fixes a bug where QEMU could successfully restore a saved VM state snapshot into a VM that had already been run, but could not restore it "from cold" using the -loadvm command line option (the symptoms being that the restored VM would run but interrupts were ignored). Finally rename vgic_init_maps to vgic_init and renamed kvm_vgic_init to kvm_vgic_map_resources. [ This patch is originally written by Peter Maydell, but I have modified it somewhat heavily, renaming various bits and moving code around. If something is broken, I am to be blamed. - Christoffer ] Acked-by: Marc Zyngier Reviewed-by: Eric Auger Signed-off-by: Peter Maydell Signed-off-by: Christoffer Dall --- include/kvm/arm_vgic.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/kvm') diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 206dcc3b3f7a..fe9783ba924c 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -274,7 +274,7 @@ struct kvm_exit_mmio; #ifdef CONFIG_KVM_ARM_VGIC int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write); int kvm_vgic_hyp_init(void); -int kvm_vgic_init(struct kvm *kvm); +int kvm_vgic_map_resources(struct kvm *kvm); int kvm_vgic_create(struct kvm *kvm); void kvm_vgic_destroy(struct kvm *kvm); void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu); @@ -321,7 +321,7 @@ static inline int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, return -ENXIO; } -static inline int kvm_vgic_init(struct kvm *kvm) +static inline int kvm_vgic_map_resources(struct kvm *kvm) { return 0; } -- cgit v1.2.3 From c52edf5f8caff878afc93c1b1e9a3d9490a9932f Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 9 Dec 2014 14:28:09 +0100 Subject: arm/arm64: KVM: Rename vgic_initialized to vgic_ready The vgic_initialized() macro currently returns the state of the vgic->ready flag, which indicates if the vgic is ready to be used when running a VM, not specifically if its internal state has been initialized. Rename the macro accordingly in preparation for a more nuanced initialization flow. Acked-by: Marc Zyngier Reviewed-by: Eric Auger Signed-off-by: Christoffer Dall --- arch/arm/kvm/arm.c | 2 +- include/kvm/arm_vgic.h | 4 ++-- virt/kvm/arm/vgic.c | 6 +++--- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'include/kvm') diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index fa4b97c5746c..c5a05f2c28ac 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -431,7 +431,7 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) * Map the VGIC hardware resources before running a vcpu the first * time on this VM. */ - if (unlikely(!vgic_initialized(vcpu->kvm))) { + if (unlikely(!vgic_ready(vcpu->kvm))) { ret = kvm_vgic_map_resources(vcpu->kvm); if (ret) return ret; diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index fe9783ba924c..3e262b9bbddf 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -287,7 +287,7 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_exit_mmio *mmio); #define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel)) -#define vgic_initialized(k) ((k)->arch.vgic.ready) +#define vgic_ready(k) ((k)->arch.vgic.ready) int vgic_v2_probe(struct device_node *vgic_node, const struct vgic_ops **ops, @@ -369,7 +369,7 @@ static inline int irqchip_in_kernel(struct kvm *kvm) return 0; } -static inline bool vgic_initialized(struct kvm *kvm) +static inline bool vgic_ready(struct kvm *kvm) { return true; } diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 1ce4e364c1e0..4edb2572ea9a 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1696,7 +1696,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, { int vcpu_id; - if (likely(vgic_initialized(kvm))) { + if (likely(vgic_ready(kvm))) { vcpu_id = vgic_update_irq_pending(kvm, cpuid, irq_num, level); if (vcpu_id >= 0) /* kick the specified vcpu */ @@ -1888,7 +1888,7 @@ int kvm_vgic_map_resources(struct kvm *kvm) mutex_lock(&kvm->lock); - if (vgic_initialized(kvm)) + if (vgic_ready(kvm)) goto out; if (IS_VGIC_ADDR_UNDEF(kvm->arch.vgic.vgic_dist_base) || @@ -2282,7 +2282,7 @@ static int vgic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) mutex_lock(&dev->kvm->lock); - if (vgic_initialized(dev->kvm) || dev->kvm->arch.vgic.nr_irqs) + if (vgic_ready(dev->kvm) || dev->kvm->arch.vgic.nr_irqs) ret = -EBUSY; else dev->kvm->arch.vgic.nr_irqs = val; -- cgit v1.2.3 From 1f57be289571d514b9412da2af25a64a81b8dd89 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 9 Dec 2014 14:30:36 +0100 Subject: arm/arm64: KVM: Add (new) vgic_initialized macro Some code paths will need to check to see if the internal state of the vgic has been initialized (such as when creating new VCPUs), so introduce such a macro that checks the nr_cpus field which is set when the vgic has been initialized. Also set nr_cpus = 0 in kvm_vgic_destroy, because the error path in vgic_init() will call this function, and code should never errornously assume the vgic to be properly initialized after an error. Acked-by: Marc Zyngier Reviewed-by: Eric Auger Signed-off-by: Christoffer Dall --- include/kvm/arm_vgic.h | 6 ++++++ virt/kvm/arm/vgic.c | 3 ++- 2 files changed, 8 insertions(+), 1 deletion(-) (limited to 'include/kvm') diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 3e262b9bbddf..ac4888dc86bc 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -287,6 +287,7 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_exit_mmio *mmio); #define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel)) +#define vgic_initialized(k) (!!((k)->arch.vgic.nr_cpus)) #define vgic_ready(k) ((k)->arch.vgic.ready) int vgic_v2_probe(struct device_node *vgic_node, @@ -369,6 +370,11 @@ static inline int irqchip_in_kernel(struct kvm *kvm) return 0; } +static inline bool vgic_initialized(struct kvm *kvm) +{ + return true; +} + static inline bool vgic_ready(struct kvm *kvm) { return true; diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 4edb2572ea9a..d862ea502167 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1780,6 +1780,7 @@ void kvm_vgic_destroy(struct kvm *kvm) dist->irq_spi_cpu = NULL; dist->irq_spi_target = NULL; dist->irq_pending_on_cpu = NULL; + dist->nr_cpus = 0; } /* @@ -1793,7 +1794,7 @@ static int vgic_init(struct kvm *kvm) int nr_cpus, nr_irqs; int ret, i, vcpu_id; - if (dist->nr_cpus) /* Already allocated */ + if (vgic_initialized(kvm)) return 0; nr_cpus = dist->nr_cpus = atomic_read(&kvm->online_vcpus); -- cgit v1.2.3 From 05971120fca43e0357789a14b3386bb56eef2201 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Fri, 12 Dec 2014 21:19:23 +0100 Subject: arm/arm64: KVM: Require in-kernel vgic for the arch timers It is curently possible to run a VM with architected timers support without creating an in-kernel VGIC, which will result in interrupts from the virtual timer going nowhere. To address this issue, move the architected timers initialization to the time when we run a VCPU for the first time, and then only initialize (and enable) the architected timers if we have a properly created and initialized in-kernel VGIC. When injecting interrupts from the virtual timer to the vgic, the current setup should ensure that this never calls an on-demand init of the VGIC, which is the only call path that could return an error from kvm_vgic_inject_irq(), so capture the return value and raise a warning if there's an error there. We also change the kvm_timer_init() function from returning an int to be a void function, since the function always succeeds. Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/kvm/arm.c | 13 +++++++++++-- include/kvm/arm_arch_timer.h | 10 ++++------ virt/kvm/arm/arch_timer.c | 30 ++++++++++++++++++++++-------- 3 files changed, 37 insertions(+), 16 deletions(-) (limited to 'include/kvm') diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 66f37c4cdf13..2d6d91001062 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -425,6 +425,7 @@ static void update_vttbr(struct kvm *kvm) static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) { + struct kvm *kvm = vcpu->kvm; int ret; if (likely(vcpu->arch.has_run_once)) @@ -436,12 +437,20 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) * Map the VGIC hardware resources before running a vcpu the first * time on this VM. */ - if (unlikely(!vgic_ready(vcpu->kvm))) { - ret = kvm_vgic_map_resources(vcpu->kvm); + if (unlikely(!vgic_ready(kvm))) { + ret = kvm_vgic_map_resources(kvm); if (ret) return ret; } + /* + * Enable the arch timers only if we have an in-kernel VGIC + * and it has been properly initialized, since we cannot handle + * interrupts from the virtual timer with a userspace gic. + */ + if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) + kvm_timer_enable(kvm); + return 0; } diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index ad9db6045b2f..b3f45a578344 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -60,7 +60,8 @@ struct arch_timer_cpu { #ifdef CONFIG_KVM_ARM_TIMER int kvm_timer_hyp_init(void); -int kvm_timer_init(struct kvm *kvm); +void kvm_timer_enable(struct kvm *kvm); +void kvm_timer_init(struct kvm *kvm); void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, const struct kvm_irq_level *irq); void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu); @@ -77,11 +78,8 @@ static inline int kvm_timer_hyp_init(void) return 0; }; -static inline int kvm_timer_init(struct kvm *kvm) -{ - return 0; -} - +static inline void kvm_timer_enable(struct kvm *kvm) {} +static inline void kvm_timer_init(struct kvm *kvm) {} static inline void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, const struct kvm_irq_level *irq) {} static inline void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) {} diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 22fa819a9b6a..1c0772b340d8 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -61,12 +61,14 @@ static void timer_disarm(struct arch_timer_cpu *timer) static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu) { + int ret; struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK; - kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, - timer->irq->irq, - timer->irq->level); + ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, + timer->irq->irq, + timer->irq->level); + WARN_ON(ret); } static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) @@ -307,12 +309,24 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) timer_disarm(timer); } -int kvm_timer_init(struct kvm *kvm) +void kvm_timer_enable(struct kvm *kvm) { - if (timecounter && wqueue) { - kvm->arch.timer.cntvoff = kvm_phys_timer_read(); + if (kvm->arch.timer.enabled) + return; + + /* + * There is a potential race here between VCPUs starting for the first + * time, which may be enabling the timer multiple times. That doesn't + * hurt though, because we're just setting a variable to the same + * variable that it already was. The important thing is that all + * VCPUs have the enabled variable set, before entering the guest, if + * the arch timers are enabled. + */ + if (timecounter && wqueue) kvm->arch.timer.enabled = 1; - } +} - return 0; +void kvm_timer_init(struct kvm *kvm) +{ + kvm->arch.timer.cntvoff = kvm_phys_timer_read(); } -- cgit v1.2.3