Report stolen time (run_delay field from schedstat) to guests via
pvclock.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Index: kvm/arch/x86/include/asm/kvm_para.h
===================================================================
--- kvm.orig/arch/x86/include/asm/kvm_para.h
+++ kvm/arch/x86/include/asm/kvm_para.h
@@ -15,9 +15,11 @@
#define KVM_FEATURE_CLOCKSOURCE 0
#define KVM_FEATURE_NOP_IO_DELAY 1
#define KVM_FEATURE_MMU_OP 2
+#define KVM_FEATURE_RUNTIME_INFO 3
#define MSR_KVM_WALL_CLOCK 0x11
#define MSR_KVM_SYSTEM_TIME 0x12
+#define MSR_KVM_RUN_TIME 0x13
#define KVM_MAX_MMU_OP_BATCH 32
@@ -50,6 +52,11 @@ struct kvm_mmu_op_release_pt {
#ifdef __KERNEL__
#include <asm/processor.h>
+struct kvm_vcpu_runtime_info {
+ u64 stolen_time; /* time spent starving */
+ u64 reserved[3]; /* for future use */
+};
+
extern void kvmclock_init(void);
Index: kvm/arch/x86/include/asm/kvm_host.h
===================================================================
--- kvm.orig/arch/x86/include/asm/kvm_host.h
+++ kvm/arch/x86/include/asm/kvm_host.h
@@ -354,6 +354,10 @@ struct kvm_vcpu_arch {
unsigned int time_offset;
struct page *time_page;
+ bool stolen_time_enable;
+ struct kvm_vcpu_runtime_info stolen_time;
+ unsigned int stolen_time_offset;
+
bool singlestep; /* guest is single stepped by KVM */
bool nmi_pending;
bool nmi_injected;
Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -507,9 +507,9 @@ static inline u32 bit(int bitno)
* kvm-specific. Those are put in the beginning of the list.
*/
-#define KVM_SAVE_MSRS_BEGIN 2
+#define KVM_SAVE_MSRS_BEGIN 3
static u32 msrs_to_save[] = {
- MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
+ MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, MSR_KVM_RUN_TIME,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
MSR_K6_STAR,
#ifdef CONFIG_X86_64
@@ -679,6 +679,7 @@ static void kvm_write_guest_time(struct
struct kvm_vcpu_arch *vcpu = &v->arch;
void *shared_kaddr;
unsigned long this_tsc_khz;
+ struct task_struct *task = current;
if ((!vcpu->time_page))
return;
@@ -700,6 +701,9 @@ static void kvm_write_guest_time(struct
vcpu->hv_clock.system_time = ts.tv_nsec +
(NSEC_PER_SEC * (u64)ts.tv_sec);
+
+ vcpu->stolen_time.stolen_time = task->sched_info.run_delay;
+
/*
* The interface expects us to write an even number signaling that the
* update is finished. Since the guest won't see the intermediate
@@ -712,6 +716,10 @@ static void kvm_write_guest_time(struct
memcpy(shared_kaddr + vcpu->time_offset, &vcpu->hv_clock,
sizeof(vcpu->hv_clock));
+ if (vcpu->stolen_time_enable)
+ memcpy(shared_kaddr + vcpu->stolen_time_offset,
+ &vcpu->stolen_time, sizeof(vcpu->stolen_time));
+
kunmap_atomic(shared_kaddr, KM_USER0);
mark_page_dirty(v->kvm, vcpu->time >> PAGE_SHIFT);
@@ -937,6 +945,35 @@ int kvm_set_msr_common(struct kvm_vcpu *
kvm_request_guest_time_update(vcpu);
break;
}
+ case MSR_KVM_RUN_TIME: {
+ struct page *page;
+ unsigned int stolen_time_offset;
+
+ if (!vcpu->arch.time_page)
+ return 1;
+
+ /* we verify if the enable bit is set... */
+ if (!(data & 1))
+ break;
+
+ /* ...but clean it before doing the actual write */
+ stolen_time_offset = data & ~(PAGE_MASK | 1);
+
+ /* that it matches the hvclock page */
+ page = gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
+ if (is_error_page(page)) {
+ kvm_release_page_clean(page);
+ return 1;
+ }
+ if (page != vcpu->arch.time_page) {
+ kvm_release_page_clean(page);
+ return 1;
+ }
+ kvm_release_page_clean(page);
+ vcpu->arch.stolen_time_offset = stolen_time_offset;
+ vcpu->arch.stolen_time_enable = 1;
+ 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:
@@ -1246,6 +1283,7 @@ int kvm_dev_ioctl_check_extension(long e
case KVM_CAP_PIT2:
case KVM_CAP_PIT_STATE2:
case KVM_CAP_SET_IDENTITY_MAP_ADDR:
+ case KVM_CAP_PVCLOCK_RUNTIME:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
Index: kvm/arch/x86/kvm/Kconfig
===================================================================
--- kvm.orig/arch/x86/kvm/Kconfig
+++ kvm/arch/x86/kvm/Kconfig
@@ -28,6 +28,7 @@ config KVM
select HAVE_KVM_IRQCHIP
select HAVE_KVM_EVENTFD
select KVM_APIC_ARCHITECTURE
+ select SCHEDSTATS
---help---
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
Index: kvm/include/linux/kvm.h
===================================================================
--- kvm.orig/include/linux/kvm.h
+++ kvm/include/linux/kvm.h
@@ -436,6 +436,7 @@ struct kvm_ioeventfd {
#endif
#define KVM_CAP_IOEVENTFD 36
#define KVM_CAP_SET_IDENTITY_MAP_ADDR 37
+#define KVM_CAP_PVCLOCK_RUNTIME 38
#ifdef KVM_CAP_IRQ_ROUTING
--
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