[RFC PATCH v3 08/16] KVM: arm64: Add a new VCPU device control group for SPE
Alexandru Elisei
alexandru.elisei at arm.com
Tue Oct 27 13:26:57 EDT 2020
From: Sudeep Holla <sudeep.holla at arm.com>
To configure the virtual SPE buffer management interrupt number, we use a
VCPU kvm_device ioctl, encapsulating the KVM_ARM_VCPU_SPE_IRQ attribute
within the KVM_ARM_VCPU_SPE_CTRL group.
After configuring the SPE, userspace is required to call the VCPU ioctl
with the attribute KVM_ARM_VCPU_SPE_INIT to initialize SPE on the VCPU.
[Alexandru E: Fixed compilation errors, don't allow userspace to set the
VCPU feature, removed unused functions, fixed mismatched
descriptions, comments and error codes, reworked logic, rebased on
top of v5.10-rc1]
Signed-off-by: Sudeep Holla <sudeep.holla at arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
Documentation/virt/kvm/devices/vcpu.rst | 40 ++++++++
arch/arm64/include/uapi/asm/kvm.h | 3 +
arch/arm64/kvm/Makefile | 1 +
arch/arm64/kvm/guest.c | 9 ++
arch/arm64/kvm/reset.c | 23 +++++
arch/arm64/kvm/spe.c | 129 ++++++++++++++++++++++++
include/kvm/arm_spe.h | 27 +++++
include/uapi/linux/kvm.h | 1 +
8 files changed, 233 insertions(+)
create mode 100644 arch/arm64/kvm/spe.c
diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst
index 2acec3b9ef65..6135b9827fbe 100644
--- a/Documentation/virt/kvm/devices/vcpu.rst
+++ b/Documentation/virt/kvm/devices/vcpu.rst
@@ -161,3 +161,43 @@ Specifies the base address of the stolen time structure for this VCPU. The
base address must be 64 byte aligned and exist within a valid guest memory
region. See Documentation/virt/kvm/arm/pvtime.rst for more information
including the layout of the stolen time structure.
+
+4. GROUP: KVM_ARM_VCPU_SPE_CTRL
+===============================
+
+:Architectures: ARM64
+
+4.1 ATTRIBUTE: KVM_ARM_VCPU_SPE_IRQ
+-----------------------------------
+
+:Parameters: in kvm_device_attr.addr the address for the SPE buffer management
+ interrupt is a pointer to an int
+
+Returns:
+
+ ======= ========================================================
+ -EBUSY The SPE buffer management interrupt is already set
+ -EINVAL Invalid SPE overflow interrupt number
+ -EFAULT Could not read the buffer management interrupt number
+ -ENXIO SPE not supported or not properly configured
+ ======= ========================================================
+
+A value describing the SPE (Statistical Profiling Extension) overflow interrupt
+number for this vcpu. This interrupt should be a PPI and the interrupt type and
+number must be same for each vcpu.
+
+4.2 ATTRIBUTE: KVM_ARM_VCPU_SPE_INIT
+------------------------------------
+
+:Parameters: no additional parameter in kvm_device_attr.addr
+
+Returns:
+
+ ======= ======================================================
+ -EBUSY SPE already initialized
+ -ENODEV GIC not initialized
+ -ENXIO SPE not supported or not properly configured
+ ======= ======================================================
+
+Request the initialization of the SPE. Must be done after initializing the
+in-kernel irqchip and after setting the interrupt number for the VCPU.
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 489e12304dbb..ca57dfb7abf0 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -360,6 +360,9 @@ struct kvm_vcpu_events {
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
#define KVM_ARM_VCPU_PVTIME_CTRL 2
#define KVM_ARM_VCPU_PVTIME_IPA 0
+#define KVM_ARM_VCPU_SPE_CTRL 3
+#define KVM_ARM_VCPU_SPE_IRQ 0
+#define KVM_ARM_VCPU_SPE_INIT 1
/* KVM_IRQ_LINE irq field index values */
#define KVM_ARM_IRQ_VCPU2_SHIFT 28
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 1504c81fbf5d..f6e76f64ffbe 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -25,3 +25,4 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
vgic/vgic-its.o vgic/vgic-debug.o
kvm-$(CONFIG_KVM_ARM_PMU) += pmu-emul.o
+kvm-$(CONFIG_KVM_ARM_SPE) += spe.o
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index dfb5218137ca..2ba790eeb782 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -926,6 +926,9 @@ int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu,
case KVM_ARM_VCPU_PVTIME_CTRL:
ret = kvm_arm_pvtime_set_attr(vcpu, attr);
break;
+ case KVM_ARM_VCPU_SPE_CTRL:
+ ret = kvm_arm_spe_set_attr(vcpu, attr);
+ break;
default:
ret = -ENXIO;
break;
@@ -949,6 +952,9 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
case KVM_ARM_VCPU_PVTIME_CTRL:
ret = kvm_arm_pvtime_get_attr(vcpu, attr);
break;
+ case KVM_ARM_VCPU_SPE_CTRL:
+ ret = kvm_arm_spe_get_attr(vcpu, attr);
+ break;
default:
ret = -ENXIO;
break;
@@ -972,6 +978,9 @@ int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
case KVM_ARM_VCPU_PVTIME_CTRL:
ret = kvm_arm_pvtime_has_attr(vcpu, attr);
break;
+ case KVM_ARM_VCPU_SPE_CTRL:
+ ret = kvm_arm_spe_has_attr(vcpu, attr);
+ break;
default:
ret = -ENXIO;
break;
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index f32490229a4c..4dc205fa4be1 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -87,6 +87,9 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_ARM_PTRAUTH_GENERIC:
r = system_has_full_ptr_auth();
break;
+ case KVM_CAP_ARM_SPE:
+ r = kvm_arm_supports_spe();
+ break;
default:
r = 0;
}
@@ -223,6 +226,19 @@ static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
return 0;
}
+static int kvm_vcpu_enable_spe(struct kvm_vcpu *vcpu)
+{
+ if (!kvm_arm_supports_spe())
+ return -EINVAL;
+
+ /* SPE is disabled if the PE is in AArch32 state */
+ if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
+ return -EINVAL;
+
+ vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_SPE;
+ return 0;
+}
+
/**
* kvm_reset_vcpu - sets core registers and sys_regs to reset value
* @vcpu: The VCPU pointer
@@ -274,6 +290,13 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
}
}
+ if (test_bit(KVM_ARM_VCPU_SPE, vcpu->arch.features)) {
+ if (kvm_vcpu_enable_spe(vcpu)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
switch (vcpu->arch.target) {
default:
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
diff --git a/arch/arm64/kvm/spe.c b/arch/arm64/kvm/spe.c
new file mode 100644
index 000000000000..f91a52cd7cd3
--- /dev/null
+++ b/arch/arm64/kvm/spe.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/uaccess.h>
+
+#include <kvm/arm_spe.h>
+#include <kvm/arm_vgic.h>
+
+static bool kvm_arm_vcpu_supports_spe(struct kvm_vcpu *vcpu)
+{
+ if (!vcpu_has_spe(vcpu))
+ return false;
+
+ if (!irqchip_in_kernel(vcpu->kvm))
+ return false;
+
+ return true;
+}
+
+static int kvm_arm_spe_init(struct kvm_vcpu *vcpu)
+{
+ if (!kvm_arm_spe_irq_initialized(vcpu))
+ return -ENXIO;
+
+ if (!vgic_initialized(vcpu->kvm))
+ return -ENODEV;
+
+ if (kvm_arm_spe_vcpu_initialized(vcpu))
+ return -EBUSY;
+
+ if (kvm_vgic_set_owner(vcpu, vcpu->arch.spe_cpu.irq_num, &vcpu->arch.spe_cpu))
+ return -ENXIO;
+
+ vcpu->arch.spe_cpu.initialized = true;
+
+ return 0;
+}
+
+static bool kvm_arm_spe_irq_is_valid(struct kvm *kvm, int irq)
+{
+ int i;
+ struct kvm_vcpu *vcpu;
+
+ /* The SPE overflow interrupt can be a PPI only */
+ if (!irq_is_ppi(irq))
+ return false;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (!kvm_arm_spe_irq_initialized(vcpu))
+ continue;
+
+ if (vcpu->arch.spe_cpu.irq_num != irq)
+ return false;
+ }
+
+ return true;
+}
+
+int kvm_arm_spe_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_SPE_IRQ: {
+ int __user *uaddr = (int __user *)(long)attr->addr;
+ int irq;
+
+ if (!kvm_arm_vcpu_supports_spe(vcpu))
+ return -ENXIO;
+
+ if (get_user(irq, uaddr))
+ return -EFAULT;
+
+ if (!kvm_arm_spe_irq_is_valid(vcpu->kvm, irq))
+ return -EINVAL;
+
+ if (kvm_arm_spe_irq_initialized(vcpu))
+ return -EBUSY;
+
+ kvm_debug("Set kvm ARM SPE irq: %d\n", irq);
+ vcpu->arch.spe_cpu.irq_num = irq;
+
+ return 0;
+ }
+ case KVM_ARM_VCPU_SPE_INIT:
+ return kvm_arm_spe_init(vcpu);
+ }
+
+ return -ENXIO;
+}
+
+int kvm_arm_spe_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_SPE_IRQ: {
+ int __user *uaddr = (int __user *)(long)attr->addr;
+ int irq;
+
+ if (!kvm_arm_vcpu_supports_spe(vcpu))
+ return -ENXIO;
+
+ if (!kvm_arm_spe_irq_initialized(vcpu))
+ return -ENXIO;
+
+ irq = vcpu->arch.spe_cpu.irq_num;
+ if (put_user(irq, uaddr))
+ return -EFAULT;
+
+ return 0;
+ }
+ }
+
+ return -ENXIO;
+}
+
+int kvm_arm_spe_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_SPE_IRQ:
+ fallthrough;
+ case KVM_ARM_VCPU_SPE_INIT:
+ if (kvm_arm_vcpu_supports_spe(vcpu))
+ return 0;
+ }
+
+ return -ENXIO;
+}
diff --git a/include/kvm/arm_spe.h b/include/kvm/arm_spe.h
index 46ec447ed013..0275e8097529 100644
--- a/include/kvm/arm_spe.h
+++ b/include/kvm/arm_spe.h
@@ -18,11 +18,38 @@ struct kvm_spe_cpu {
bool initialized; /* Feature is initialized on VCPU */
};
+#define kvm_arm_spe_irq_initialized(v) \
+ ((v)->arch.spe_cpu.irq_num >= VGIC_NR_SGIS && \
+ (v)->arch.spe_cpu.irq_num < VGIC_MAX_PRIVATE)
+#define kvm_arm_spe_vcpu_initialized(v) ((v)->arch.spe_cpu.initialized)
+
+int kvm_arm_spe_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
+int kvm_arm_spe_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
+int kvm_arm_spe_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
+
#else
#define kvm_arm_supports_spe() false
struct kvm_spe_cpu {
};
+#define kvm_arm_spe_irq_initialized(v) false
+#define kvm_arm_spe_vcpu_initialized(v) false
+
+static inline int kvm_arm_spe_set_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ return -ENXIO;
+}
+static inline int kvm_arm_spe_get_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ return -ENXIO;
+}
+static inline int kvm_arm_spe_has_attr(struct kvm_vcpu *vcpu,
+ struct kvm_device_attr *attr)
+{
+ return -ENXIO;
+}
#endif /* CONFIG_KVM_ARM_SPE */
#endif /* __ASM_ARM_KVM_SPE_H */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ca41220b40b8..96228b823711 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1053,6 +1053,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_X86_USER_SPACE_MSR 188
#define KVM_CAP_X86_MSR_FILTER 189
#define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190
+#define KVM_CAP_ARM_SPE 191
#ifdef KVM_CAP_IRQ_ROUTING
--
2.29.1
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