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Message-Id: <20120502100856.13206.88245.sendpatchset@codeblue.in.ibm.com>
Date: Wed, 02 May 2012 15:38:56 +0530
From: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>
To: Jeremy Fitzhardinge <jeremy@...p.org>,
Greg Kroah-Hartman <gregkh@...e.de>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
"H. Peter Anvin" <hpa@...or.com>, Avi Kivity <avi@...hat.com>,
X86 <x86@...nel.org>, Gleb Natapov <gleb@...hat.com>,
Ingo Molnar <mingo@...hat.com>,
Marcelo Tosatti <mtosatti@...hat.com>
Cc: Attilio Rao <attilio.rao@...rix.com>,
Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
linux-doc@...r.kernel.org,
Virtualization <virtualization@...ts.linux-foundation.org>,
Xen Devel <xen-devel@...ts.xensource.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
KVM <kvm@...r.kernel.org>, Andi Kleen <andi@...stfloor.org>,
Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>,
Stefano Stabellini <stefano.stabellini@...citrix.com>,
Stephan Diestelhorst <stephan.diestelhorst@....com>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH RFC V8 13/17] 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.
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>
---
arch/x86/include/asm/kvm_host.h | 4 ++++
arch/x86/include/asm/kvm_para.h | 2 ++
arch/x86/kvm/cpuid.c | 3 ++-
arch/x86/kvm/x86.c | 37 +++++++++++++++++++++++++++++++++++++
include/linux/kvm_para.h | 1 +
5 files changed, 46 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e216ba0..e187a9b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -481,6 +481,10 @@ struct kvm_vcpu_arch {
u64 length;
u64 status;
} osvw;
+ /* pv related host specific info */
+ struct {
+ bool pv_unhalted;
+ } pv;
};
struct kvm_lpage_info {
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 734c376..5b647ea 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.
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 9fed5be..7c93806 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 91a5e98..f188cdc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4993,6 +4993,36 @@ 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) {
+ /*
+ * Setting unhalt flag here can result in spurious runnable
+ * state when unhalt reset does not happen in vcpu_block.
+ * But that is harmless since that should soon result in halt.
+ */
+ vcpu->arch.pv.pv_unhalted = true;
+ /* We need everybody see unhalt before vcpu unblocks */
+ smp_wmb();
+ kvm_vcpu_kick(vcpu);
+ }
+}
+
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
@@ -5026,6 +5056,10 @@ 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;
@@ -5409,6 +5443,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
{
switch(vcpu->arch.mp_state) {
case KVM_MP_STATE_HALTED:
+ vcpu->arch.pv.pv_unhalted = false;
vcpu->arch.mp_state =
KVM_MP_STATE_RUNNABLE;
case KVM_MP_STATE_RUNNABLE:
@@ -6128,6 +6163,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
BUG_ON(vcpu->kvm == NULL);
kvm = vcpu->kvm;
+ vcpu->arch.pv.pv_unhalted = false;
vcpu->arch.emulate_ctxt.ops = &emulate_ops;
if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))
vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
@@ -6394,6 +6430,7 @@ 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->arch.pv.pv_unhalted
|| atomic_read(&vcpu->arch.nmi_queued) ||
(kvm_arch_interrupt_allowed(vcpu) &&
kvm_cpu_has_interrupt(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
--
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