[patch 1/3] KVM: x86: add per-vcpu option to set guest vcpu -RT priority

Marcelo Tosatti
2017-09-21T11:44:31Z

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[-- Type: text/plain, Size: 3906 bytes --]

In preparation to the patch which adds a hypercall for
the guest vcpu to change states between:

-> SCHED_FIFO.
-> SCHED_NORMAL.

Add controls to:

1) Allow control to which priority SCHED_FIFO state will be in
place (in the host).

2) Enable/disable ability to use the hypercall, on a per-vcpu
basis.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---
arch/x86/include/asm/kvm_host.h | 4 ++++
arch/x86/include/uapi/asm/kvm.h | 5 +++++
arch/x86/kvm/x86.c | 29 +++++++++++++++++++++++++++++
include/uapi/linux/kvm.h | 3 +++
4 files changed, 41 insertions(+)

Index: kvm.fifopriohc-submit/arch/x86/include/asm/kvm_host.h
===================================================================
--- kvm.fifopriohc-submit.orig/arch/x86/include/asm/kvm_host.h
+++ kvm.fifopriohc-submit/arch/x86/include/asm/kvm_host.h
@@ -688,6 +688,10 @@ struct kvm_vcpu_arch {

/* GPA available (AMD only) */
bool gpa_available;
+
+ /* Enable RT prio hypercall */
+ bool enable_rt_prio_hc;
+ int rt_sched_priority;
};

struct kvm_lpage_info {
Index: kvm.fifopriohc-submit/arch/x86/kvm/x86.c
===================================================================
--- kvm.fifopriohc-submit.orig/arch/x86/kvm/x86.c
+++ kvm.fifopriohc-submit/arch/x86/kvm/x86.c
@@ -2683,6 +2683,7 @@ int kvm_vm_ioctl_check_extension(struct
case KVM_CAP_SET_BOOT_CPU_ID:
case KVM_CAP_SPLIT_IRQCHIP:
case KVM_CAP_IMMEDIATE_EXIT:
+ case KVM_CAP_VCPU_RT_PRIO_HC:
r = 1;
break;
case KVM_CAP_ADJUST_CLOCK:
@@ -3386,6 +3387,25 @@ static int kvm_set_guest_paused(struct k
return 0;
}

+static int kvm_vcpu_ioctl_set_rt_prio_hc(struct kvm_vcpu *vcpu,
+ struct kvm_vcpu_rt_prio *rt_prio)
+{
+ if (rt_prio->enabled == 0) {
+ vcpu->arch.enable_rt_prio_hc = false;
+ return 0;
+ }
+
+ if (rt_prio->sched_priority < 1 ||
+ rt_prio->sched_priority > 99)
+ return -EINVAL;
+
+
+ vcpu->arch.enable_rt_prio_hc = true;
+ vcpu->arch.rt_sched_priority = rt_prio->sched_priority;
+
+ return 0;
+}
+
static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
struct kvm_enable_cap *cap)
{
@@ -3682,6 +3702,15 @@ long kvm_arch_vcpu_ioctl(struct file *fi
r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
break;
}
+ case KVM_SET_VCPU_RT_PRIO_HC: {
+ struct kvm_vcpu_rt_prio rt_prio;
+
+ r = -EFAULT;
+ if (copy_from_user(&rt_prio, argp, sizeof(rt_prio)))
+ goto out;
+ r = kvm_vcpu_ioctl_set_rt_prio_hc(vcpu, &rt_prio);
+ break;
+ }
default:
r = -EINVAL;
}
Index: kvm.fifopriohc-submit/include/uapi/linux/kvm.h
===================================================================
--- kvm.fifopriohc-submit.orig/include/uapi/linux/kvm.h
+++ kvm.fifopriohc-submit/include/uapi/linux/kvm.h
@@ -929,6 +929,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_PPC_SMT_POSSIBLE 147
#define KVM_CAP_HYPERV_SYNIC2 148
#define KVM_CAP_HYPERV_VP_INDEX 149
+#define KVM_CAP_VCPU_RT_PRIO_HC 150

#ifdef KVM_CAP_IRQ_ROUTING

@@ -1355,6 +1356,8 @@ struct kvm_s390_ucas_mapping {
/* Available with KVM_CAP_S390_CMMA_MIGRATION */
#define KVM_S390_GET_CMMA_BITS _IOWR(KVMIO, 0xb8, struct kvm_s390_cmma_log)
#define KVM_S390_SET_CMMA_BITS _IOW(KVMIO, 0xb9, struct kvm_s390_cmma_log)
+/* Available with KVM_CAP_VCPU_RT_PRIO_HC */
+#define KVM_SET_VCPU_RT_PRIO_HC _IOW(KVMIO, 0xba, struct kvm_vcpu_rt_prio)

#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
Index: kvm.fifopriohc-submit/arch/x86/include/uapi/asm/kvm.h
===================================================================
--- kvm.fifopriohc-submit.orig/arch/x86/include/uapi/asm/kvm.h
+++ kvm.fifopriohc-submit/arch/x86/include/uapi/asm/kvm.h
@@ -353,6 +353,11 @@ struct kvm_xcrs {
__u64 padding[16];
};

+struct kvm_vcpu_rt_prio {
+ __u32 enabled;
+ __u32 sched_priority;
+};
+
/* definition of registers in kvm_run */
struct kvm_sync_regs {
};