| Message ID | 1417113660-23610-2-git-send-email-christoffer.dall@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 27 November 2014 at 18:40, Christoffer Dall <christoffer.dall@linaro.org> wrote: > 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. > > Implment the expected functionality and clarify the ABI. ("Implement", if you have to respin.) > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 9e193c8..4dcc8c2 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -663,6 +663,8 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, > */ > if (__test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) > vcpu->arch.pause = true; > + else > + vcpu->arch.pause = false; Out of curiosity, why do we have to test-and-clear the bit rather than just testing it? thanks -- PMM
On Thu, Nov 27, 2014 at 10:44:29PM +0000, Peter Maydell wrote: > On 27 November 2014 at 18:40, Christoffer Dall > <christoffer.dall@linaro.org> wrote: > > 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. > > > > Implment the expected functionality and clarify the ABI. > > ("Implement", if you have to respin.) > > > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > > index 9e193c8..4dcc8c2 100644 > > --- a/arch/arm/kvm/arm.c > > +++ b/arch/arm/kvm/arm.c > > @@ -663,6 +663,8 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, > > */ > > if (__test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) > > vcpu->arch.pause = true; > > + else > > + vcpu->arch.pause = false; > > Out of curiosity, why do we have to test-and-clear the bit rather than > just testing it? > No reason, I think we used to do this when we were always testing the flag directly instead of through the pause flag. I'll add a change of this. -Christoffer
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 7610eaa..bb82a90 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. diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 9e193c8..4dcc8c2 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -663,6 +663,8 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, */ if (__test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) vcpu->arch.pause = true; + else + vcpu->arch.pause = false; return 0; }
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. Implment the expected functionality and clarify the ABI. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> --- Documentation/virtual/kvm/api.txt | 3 ++- arch/arm/kvm/arm.c | 2 ++ 2 files changed, 4 insertions(+), 1 deletion(-)