From 3ad8b3de526a76fbe9466b366059e4958957b88f Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Thu, 16 Oct 2014 16:14:43 +0200 Subject: arm/arm64: KVM: Correct KVM_ARM_VCPU_INIT power off option The implementation of KVM_ARM_VCPU_INIT is currently not doing what userspace expects, namely making sure that a vcpu which may have been turned off using PSCI is returned to its initial state, which would be powered on if userspace does not set the KVM_ARM_VCPU_POWER_OFF flag. Implement the expected functionality and clarify the ABI. Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- Documentation/virtual/kvm/api.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 7610eaa4d491..bb82a906e51e 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2455,7 +2455,8 @@ should be created before this ioctl is invoked. Possible features: - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. - Depends on KVM_CAP_ARM_PSCI. + Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on + and execute guest code when KVM_RUN is called. - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 for the CPU. -- cgit v1.2.3 From f7fa034dc8559c7d7326bfc8bd1a26175abd931a Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Thu, 16 Oct 2014 16:40:53 +0200 Subject: arm/arm64: KVM: Clarify KVM_ARM_VCPU_INIT ABI It is not clear that this ioctl can be called multiple times for a given vcpu. Userspace already does this, so clarify the ABI. Also specify that userspace is expected to always make secondary and subsequent calls to the ioctl with the same parameters for the VCPU as the initial call (which userspace also already does). Add code to check that userspace doesn't violate that ABI in the future, and move the kvm_vcpu_set_target() function which is currently duplicated between the 32-bit and 64-bit versions in guest.c to a common static function in arm.c, shared between both architectures. Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- Documentation/virtual/kvm/api.txt | 5 +++++ arch/arm/include/asm/kvm_host.h | 2 -- arch/arm/kvm/arm.c | 43 +++++++++++++++++++++++++++++++++++++++ arch/arm/kvm/guest.c | 25 ----------------------- arch/arm64/include/asm/kvm_host.h | 2 -- arch/arm64/kvm/guest.c | 25 ----------------------- 6 files changed, 48 insertions(+), 54 deletions(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index bb82a906e51e..81f1b974c06a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2453,6 +2453,11 @@ return ENOEXEC for that vcpu. Note that because some registers reflect machine topology, all vcpus should be created before this ioctl is invoked. +Userspace can call this function multiple times for a given vcpu, including +after the vcpu has been run. This will reset the vcpu to its initial +state. All calls to this function after the initial call must use the same +target and same set of feature flags, otherwise EINVAL will be returned. + Possible features: - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 53036e21756b..254e0650e48b 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -150,8 +150,6 @@ struct kvm_vcpu_stat { u32 halt_wakeup; }; -int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, - const struct kvm_vcpu_init *init); int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init); unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu); int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 24c9ca4076b2..4043769583e7 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -263,6 +263,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) { /* Force users to call KVM_ARM_VCPU_INIT */ vcpu->arch.target = -1; + bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); /* Set up the timer */ kvm_timer_vcpu_init(vcpu); @@ -649,6 +650,48 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, return -EINVAL; } +static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, + const struct kvm_vcpu_init *init) +{ + unsigned int i; + int phys_target = kvm_target_cpu(); + + if (init->target != phys_target) + return -EINVAL; + + /* + * Secondary and subsequent calls to KVM_ARM_VCPU_INIT must + * use the same target. + */ + if (vcpu->arch.target != -1 && vcpu->arch.target != init->target) + return -EINVAL; + + /* -ENOENT for unknown features, -EINVAL for invalid combinations. */ + for (i = 0; i < sizeof(init->features) * 8; i++) { + bool set = (init->features[i / 32] & (1 << (i % 32))); + + if (set && i >= KVM_VCPU_MAX_FEATURES) + return -ENOENT; + + /* + * Secondary and subsequent calls to KVM_ARM_VCPU_INIT must + * use the same feature set. + */ + if (vcpu->arch.target != -1 && i < KVM_VCPU_MAX_FEATURES && + test_bit(i, vcpu->arch.features) != set) + return -EINVAL; + + if (set) + set_bit(i, vcpu->arch.features); + } + + vcpu->arch.target = phys_target; + + /* Now we know what it is, we can reset it. */ + return kvm_reset_vcpu(vcpu); +} + + static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init) { diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c index 8c97208b9b97..384bab67c462 100644 --- a/arch/arm/kvm/guest.c +++ b/arch/arm/kvm/guest.c @@ -273,31 +273,6 @@ int __attribute_const__ kvm_target_cpu(void) } } -int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, - const struct kvm_vcpu_init *init) -{ - unsigned int i; - - /* We can only cope with guest==host and only on A15/A7 (for now). */ - if (init->target != kvm_target_cpu()) - return -EINVAL; - - vcpu->arch.target = init->target; - bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); - - /* -ENOENT for unknown features, -EINVAL for invalid combinations. */ - for (i = 0; i < sizeof(init->features) * 8; i++) { - if (test_bit(i, (void *)init->features)) { - if (i >= KVM_VCPU_MAX_FEATURES) - return -ENOENT; - set_bit(i, vcpu->arch.features); - } - } - - /* Now we know what it is, we can reset it. */ - return kvm_reset_vcpu(vcpu); -} - int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init) { int target = kvm_target_cpu(); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2012c4ba8d67..65c615294589 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -165,8 +165,6 @@ struct kvm_vcpu_stat { u32 halt_wakeup; }; -int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, - const struct kvm_vcpu_init *init); int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init); unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu); int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 84d5959ff874..9535bd555d1d 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -296,31 +296,6 @@ int __attribute_const__ kvm_target_cpu(void) return -EINVAL; } -int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, - const struct kvm_vcpu_init *init) -{ - unsigned int i; - int phys_target = kvm_target_cpu(); - - if (init->target != phys_target) - return -EINVAL; - - vcpu->arch.target = phys_target; - bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); - - /* -ENOENT for unknown features, -EINVAL for invalid combinations. */ - for (i = 0; i < sizeof(init->features) * 8; i++) { - if (init->features[i / 32] & (1 << (i % 32))) { - if (i >= KVM_VCPU_MAX_FEATURES) - return -ENOENT; - set_bit(i, vcpu->arch.features); - } - } - - /* Now we know what it is, we can reset it. */ - return kvm_reset_vcpu(vcpu); -} - int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init) { int target = kvm_target_cpu(); -- cgit v1.2.3 From cf5d318865e25f887d49a0c6083bbc6dcd1905b1 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Thu, 16 Oct 2014 17:00:18 +0200 Subject: arm/arm64: KVM: Turn off vcpus on PSCI shutdown/reboot When a vcpu calls SYSTEM_OFF or SYSTEM_RESET with PSCI v0.2, the vcpus should really be turned off for the VM adhering to the suggestions in the PSCI spec, and it's the sane thing to do. Also, clarify the behavior and expectations for exits to user space with the KVM_EXIT_SYSTEM_EVENT case. Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- Documentation/virtual/kvm/api.txt | 9 +++++++++ arch/arm/kvm/psci.c | 18 ++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 1 + 3 files changed, 28 insertions(+) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 81f1b974c06a..228f9cf5a5b5 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2957,6 +2957,15 @@ HVC instruction based PSCI call from the vcpu. The 'type' field describes the system-level event type. The 'flags' field describes architecture specific flags for the system-level event. +Valid values for 'type' are: + KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the + VM. Userspace is not obliged to honour this, and if it does honour + this does not need to destroy the VM synchronously (ie it may call + KVM_RUN again before shutdown finally occurs). + KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. + As with SHUTDOWN, userspace can choose to ignore the request, or + to schedule the reset to occur in the future and may call KVM_RUN again. + /* Fix the size of the union. */ char padding[256]; }; diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c index 09cf37737ee2..58cb3248d277 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -15,6 +15,7 @@ * along with this program. If not, see . */ +#include #include #include @@ -166,6 +167,23 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type) { + int i; + struct kvm_vcpu *tmp; + + /* + * The KVM ABI specifies that a system event exit may call KVM_RUN + * again and may perform shutdown/reboot at a later time that when the + * actual request is made. Since we are implementing PSCI and a + * caller of PSCI reboot and shutdown expects that the system shuts + * down or reboots immediately, let's make sure that VCPUs are not run + * after this call is handled and before the VCPUs have been + * re-initialized. + */ + kvm_for_each_vcpu(i, tmp, vcpu->kvm) { + tmp->arch.pause = true; + kvm_vcpu_kick(tmp); + } + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); vcpu->run->system_event.type = type; vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 65c615294589..0b7dfdb931df 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -198,6 +198,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void); struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void); u64 kvm_call_hyp(void *hypfn, ...); +void force_vm_exit(const cpumask_t *mask); int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, int exception_index); -- cgit v1.2.3