On 2015/12/15 23:33, Marc Zyngier wrote:
On 15/12/15 08:49, Shannon Zhao wrote:
>From: Shannon Zhao<shannon.zhao@xxxxxxxxxx>
>
>Add a new kvm device type KVM_DEV_TYPE_ARM_PMU_V3 for ARM PMU. Implement
>the kvm_device_ops for it.
>
>Signed-off-by: Shannon Zhao<shannon.zhao@xxxxxxxxxx>
>---
> Documentation/virtual/kvm/devices/arm-pmu.txt | 16 ++++
> arch/arm64/include/uapi/asm/kvm.h | 3 +
> include/linux/kvm_host.h | 1 +
> include/uapi/linux/kvm.h | 2 +
> virt/kvm/arm/pmu.c | 115 ++++++++++++++++++++++++++
> virt/kvm/kvm_main.c | 4 +
> 6 files changed, 141 insertions(+)
> create mode 100644 Documentation/virtual/kvm/devices/arm-pmu.txt
>
>diff --git a/Documentation/virtual/kvm/devices/arm-pmu.txt b/Documentation/virtual/kvm/devices/arm-pmu.txt
>new file mode 100644
>index 0000000..5121f1f
>--- /dev/null
>+++ b/Documentation/virtual/kvm/devices/arm-pmu.txt
>@@ -0,0 +1,16 @@
>+ARM Virtual Performance Monitor Unit (vPMU)
>+===========================================
>+
>+Device types supported:
>+ KVM_DEV_TYPE_ARM_PMU_V3 ARM Performance Monitor Unit v3
>+
>+Instantiate one PMU instance for per VCPU through this API.
>+
>+Groups:
>+ KVM_DEV_ARM_PMU_GRP_IRQ
>+ Attributes:
>+ A value describing the interrupt number of PMU overflow interrupt. This
>+ interrupt should be a PPI.
>+
>+ Errors:
>+ -EINVAL: Value set is out of the expected range (from 16 to 31)
>diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>index 2d4ca4b..568afa2 100644
>--- a/arch/arm64/include/uapi/asm/kvm.h
>+++ b/arch/arm64/include/uapi/asm/kvm.h
>@@ -204,6 +204,9 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_GRP_CTRL 4
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
>
>+/* Device Control API: ARM PMU */
>+#define KVM_DEV_ARM_PMU_GRP_IRQ 0
>+
> /* KVM_IRQ_LINE irq field index values */
> #define KVM_ARM_IRQ_TYPE_SHIFT 24
> #define KVM_ARM_IRQ_TYPE_MASK 0xff
>diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>index c923350..608dea6 100644
>--- a/include/linux/kvm_host.h
>+++ b/include/linux/kvm_host.h
>@@ -1161,6 +1161,7 @@ extern struct kvm_device_ops kvm_mpic_ops;
> extern struct kvm_device_ops kvm_xics_ops;
> extern struct kvm_device_ops kvm_arm_vgic_v2_ops;
> extern struct kvm_device_ops kvm_arm_vgic_v3_ops;
>+extern struct kvm_device_ops kvm_arm_pmu_ops;
>
> #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
>
>diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>index 03f3618..4ba6fdd 100644
>--- a/include/uapi/linux/kvm.h
>+++ b/include/uapi/linux/kvm.h
>@@ -1032,6 +1032,8 @@ enum kvm_device_type {
> #define KVM_DEV_TYPE_FLIC KVM_DEV_TYPE_FLIC
> KVM_DEV_TYPE_ARM_VGIC_V3,
> #define KVM_DEV_TYPE_ARM_VGIC_V3 KVM_DEV_TYPE_ARM_VGIC_V3
>+ KVM_DEV_TYPE_ARM_PMU_V3,
>+#define KVM_DEV_TYPE_ARM_PMU_V3 KVM_DEV_TYPE_ARM_PMU_V3
> KVM_DEV_TYPE_MAX,
> };
>
>diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
>index d113ee4..1965d0d 100644
>--- a/virt/kvm/arm/pmu.c
>+++ b/virt/kvm/arm/pmu.c
>@@ -19,6 +19,7 @@
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> #include <linux/perf_event.h>
>+#include <linux/uaccess.h>
> #include <asm/kvm_emulate.h>
> #include <kvm/arm_pmu.h>
> #include <kvm/arm_vgic.h>
>@@ -357,3 +358,117 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
>
> pmc->perf_event = event;
> }
>+
>+static inline bool kvm_arm_pmu_initialized(struct kvm_vcpu *vcpu)
>+{
>+ return vcpu->arch.pmu.irq_num != -1;
>+}
>+
>+static int kvm_arm_pmu_irq_access(struct kvm *kvm, int *irq, bool is_set)
>+{
>+ int j;
>+ struct kvm_vcpu *vcpu;
>+
>+ kvm_for_each_vcpu(j, vcpu, kvm) {
>+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
>+
>+ if (!is_set) {
>+ if (!kvm_arm_pmu_initialized(vcpu))
>+ return -EBUSY;
Returning -EBUSY is a bit odd. Maybe -EINVAL? But this seems weird
anyway. Actually, why would you return an error in this case?
While this is a unexpected operation from user space and it's already
initialized and working, so I think it should return an error to user
and tell user that it's already initialized and working (this should
mean "busy" ?).
--
Shannon
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