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Subject[PATCH v2 2/7] KVM-HV: Add VCPU running/pre-empted state for guest
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Date
Hypervisor code to indicate guest running/pre-empteded status through
msr.

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
---
arch/x86/include/asm/kvm_host.h | 7 ++++++
arch/x86/kvm/cpuid.c | 1 +
arch/x86/kvm/x86.c | 45 ++++++++++++++++++++++++++++++++++++++-
3 files changed, 52 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dad475b..12fe3c7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -418,6 +418,13 @@ struct kvm_vcpu_arch {
struct kvm_steal_time steal;
} st;

+ /* indicates vcpu is running or preempted */
+ struct {
+ u64 msr_val;
+ struct gfn_to_hva_cache data;
+ struct kvm_vcpu_state vs;
+ } v_state;
+
u64 last_guest_tsc;
u64 last_kernel_ns;
u64 last_host_tsc;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7c93806..0588984 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -409,6 +409,7 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
(1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
+ (1 << KVM_FEATURE_VCPU_STATE) |
(1 << KVM_FEATURE_PV_UNHALT);

if (sched_info_on())
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8e5f57b..264f172 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -789,12 +789,13 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc);
* kvm-specific. Those are put in the beginning of the list.
*/

-#define KVM_SAVE_MSRS_BEGIN 9
+#define KVM_SAVE_MSRS_BEGIN 10
static u32 msrs_to_save[] = {
MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
+ MSR_KVM_VCPU_STATE,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
MSR_STAR,
#ifdef CONFIG_X86_64
@@ -1539,6 +1540,32 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
&vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
}

+static void kvm_set_vcpu_state(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_state *vs = &vcpu->arch.v_state.vs;
+ struct gfn_to_hva_cache *ghc = &vcpu->arch.v_state.data;
+
+ if (!(vcpu->arch.v_state.msr_val & KVM_MSR_ENABLED))
+ return;
+
+ vs->state = 1;
+ kvm_write_guest_cached(vcpu->kvm, ghc, vs, 2*sizeof(__u32));
+ smp_wmb();
+}
+
+static void kvm_clear_vcpu_state(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_state *vs = &vcpu->arch.v_state.vs;
+ struct gfn_to_hva_cache *ghc = &vcpu->arch.v_state.data;
+
+ if (!(vcpu->arch.v_state.msr_val & KVM_MSR_ENABLED))
+ return;
+
+ vs->state = 0;
+ kvm_write_guest_cached(vcpu->kvm, ghc, vs, 2*sizeof(__u32));
+ smp_wmb();
+}
+
int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
bool pr = false;
@@ -1654,6 +1681,14 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)

break;

+ case MSR_KVM_VCPU_STATE:
+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.v_state.data,
+ data & KVM_VCPU_STATE_VALID_BITS))
+ return 1;
+
+ vcpu->arch.v_state.msr_val = data;
+ break;
+
case MSR_IA32_MCG_CTL:
case MSR_IA32_MCG_STATUS:
case MSR_IA32_MC0_CTL ... MSR_IA32_MC0_CTL + 4 * KVM_MAX_MCE_BANKS - 1:
@@ -1974,6 +2009,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
case MSR_KVM_STEAL_TIME:
data = vcpu->arch.st.msr_val;
break;
+ case MSR_KVM_VCPU_STATE:
+ data = vcpu->arch.v_state.msr_val;
+ break;
case MSR_IA32_P5_MC_ADDR:
case MSR_IA32_P5_MC_TYPE:
case MSR_IA32_MCG_CAP:
@@ -5324,6 +5362,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
kvm_load_guest_fpu(vcpu);
kvm_load_guest_xcr0(vcpu);

+ kvm_set_vcpu_state(vcpu);
+
vcpu->mode = IN_GUEST_MODE;

/* We should set ->mode before check ->requests,
@@ -5340,6 +5380,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
local_irq_enable();
preempt_enable();
kvm_x86_ops->cancel_injection(vcpu);
+ kvm_clear_vcpu_state(vcpu);
r = 1;
goto out;
}
@@ -5374,6 +5415,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)

vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu);

+ kvm_clear_vcpu_state(vcpu);
vcpu->mode = OUTSIDE_GUEST_MODE;
smp_wmb();
local_irq_enable();
@@ -6029,6 +6071,7 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
kvm_make_request(KVM_REQ_EVENT, vcpu);
vcpu->arch.apf.msr_val = 0;
vcpu->arch.st.msr_val = 0;
+ vcpu->arch.v_state.msr_val = 0;

kvmclock_reset(vcpu);



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