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Date: Fri, 23 Mar 2012 13:37:04 +0530
From: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>
To: Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>
Cc: X86 <x86@...nel.org>, Avi Kivity <avi@...hat.com>,
Marcelo Tosatti <mtosatti@...hat.com>,
Jeremy Fitzhardinge <jeremy@...p.org>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Greg Kroah-Hartman <gregkh@...e.de>,
Alexander Graf <agraf@...e.de>,
Stefano Stabellini <stefano.stabellini@...citrix.com>,
Gleb Natapov <gleb@...hat.com>,
Randy Dunlap <rdunlap@...otime.net>, linux-doc@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>,
Virtualization <virtualization@...ts.linux-foundation.org>,
Xen <xen-devel@...ts.xensource.com>,
Sasha Levin <levinsasha928@...il.com>,
Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
Subject: [PATCH RFC V5 2/6] kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks
From: Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
KVM_HC_KICK_CPU allows the calling vcpu to kick another vcpu out of halt state.
The presence of these hypercalls is indicated to guest via
KVM_FEATURE_PV_UNHALT/KVM_CAP_PV_UNHALT.
Signed-off-by: Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
Signed-off-by: Suzuki Poulose <suzuki@...ibm.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>
---
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 734c376..9234f13 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -16,12 +16,14 @@
#define KVM_FEATURE_CLOCKSOURCE 0
#define KVM_FEATURE_NOP_IO_DELAY 1
#define KVM_FEATURE_MMU_OP 2
+
/* This indicates that the new set of kvmclock msrs
* are available. The use of 0x11 and 0x12 is deprecated
*/
#define KVM_FEATURE_CLOCKSOURCE2 3
#define KVM_FEATURE_ASYNC_PF 4
#define KVM_FEATURE_STEAL_TIME 5
+#define KVM_FEATURE_PV_UNHALT 6
/* The last 8 bits are used to indicate how to interpret the flags field
* in pvclock structure. If no bits are set, all flags are ignored.
@@ -32,6 +34,7 @@
#define MSR_KVM_SYSTEM_TIME 0x12
#define KVM_MSR_ENABLED 1
+
/* Custom MSRs falls in the range 0x4b564d00-0x4b564dff */
#define MSR_KVM_WALL_CLOCK_NEW 0x4b564d00
#define MSR_KVM_SYSTEM_TIME_NEW 0x4b564d01
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 89b02bf..61388b9 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -408,7 +408,8 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
(1 << KVM_FEATURE_NOP_IO_DELAY) |
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
- (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
+ (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
+ (1 << KVM_FEATURE_PV_UNHALT);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9cbfc06..bd5ef91 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2079,6 +2079,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_XSAVE:
case KVM_CAP_ASYNC_PF:
case KVM_CAP_GET_TSC_KHZ:
+ case KVM_CAP_PV_UNHALT:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
@@ -4913,6 +4914,30 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
return 1;
}
+/*
+ * kvm_pv_kick_cpu_op: Kick a vcpu.
+ *
+ * @apicid - apicid of vcpu to be kicked.
+ */
+static void kvm_pv_kick_cpu_op(struct kvm *kvm, int apicid)
+{
+ struct kvm_vcpu *vcpu = NULL;
+ int i;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (!kvm_apic_present(vcpu))
+ continue;
+
+ if (kvm_apic_match_dest(vcpu, 0, 0, apicid, 0))
+ break;
+ }
+ if (vcpu) {
+ vcpu->pv_unhalted = 1;
+ smp_mb();
+ kvm_vcpu_kick(vcpu);
+ }
+}
+
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
@@ -4946,6 +4971,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
case KVM_HC_VAPIC_POLL_IRQ:
ret = 0;
break;
+ case KVM_HC_KICK_CPU:
+ kvm_pv_kick_cpu_op(vcpu->kvm, a0);
+ ret = 0;
+ break;
default:
ret = -KVM_ENOSYS;
break;
@@ -6174,6 +6203,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
!vcpu->arch.apf.halted)
|| !list_empty_careful(&vcpu->async_pf.done)
|| vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED
+ || vcpu->pv_unhalted
|| atomic_read(&vcpu->arch.nmi_queued) ||
(kvm_arch_interrupt_allowed(vcpu) &&
kvm_cpu_has_interrupt(vcpu));
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 68e67e5..e822d96 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -558,6 +558,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_PPC_PAPR 68
#define KVM_CAP_S390_GMAP 71
#define KVM_CAP_TSC_DEADLINE_TIMER 72
+#define KVM_CAP_PV_UNHALT 73
#ifdef KVM_CAP_IRQ_ROUTING
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 900c763..433ae97 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -158,6 +158,7 @@ struct kvm_vcpu {
#endif
struct kvm_vcpu_arch arch;
+ int pv_unhalted;
};
static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu)
diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
index ff476dd..38226e1 100644
--- a/include/linux/kvm_para.h
+++ b/include/linux/kvm_para.h
@@ -19,6 +19,7 @@
#define KVM_HC_MMU_OP 2
#define KVM_HC_FEATURES 3
#define KVM_HC_PPC_MAP_MAGIC_PAGE 4
+#define KVM_HC_KICK_CPU 5
/*
* hypercalls use architecture specific
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a91f980..d3b98b1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -226,6 +226,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
vcpu->pid = NULL;
+ vcpu->pv_unhalted = 0;
init_waitqueue_head(&vcpu->wq);
kvm_async_pf_vcpu_init(vcpu);
@@ -1567,6 +1568,9 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
if (kvm_arch_vcpu_runnable(vcpu)) {
+ vcpu->pv_unhalted = 0;
+ /* preventing reordering should be enough here */
+ barrier();
kvm_make_request(KVM_REQ_UNHALT, vcpu);
break;
}
--
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