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authorPaolo Bonzini <pbonzini@redhat.com>2026-02-09 18:17:01 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2026-02-09 18:17:01 +0100
commitc14f646638ddf647e080d4755e9a008dc9db03e7 (patch)
tree76e0e71c0366a5627ed20947df88a2c508cf540a
parent05f7e89ab9731565d8a62e3b5d1ec206485eeb0b (diff)
parent2d94a3f7088b69ae25e27fb98d7f1ef572c843f9 (diff)
Merge tag 'loongarch-kvm-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD
LoongArch KVM changes for v6.20 1. Add more CPUCFG mask bits. 2. Improve feature detection. 3. Add FPU/LBT delay load support. 4. Set default return value in KVM IO bus ops. 5. Add paravirt preempt feature support. 6. Add KVM steal time test case for tools/selftests.
-rw-r--r--arch/loongarch/include/asm/kvm_host.h9
-rw-r--r--arch/loongarch/include/asm/kvm_para.h4
-rw-r--r--arch/loongarch/include/asm/loongarch.h1
-rw-r--r--arch/loongarch/include/asm/qspinlock.h4
-rw-r--r--arch/loongarch/include/uapi/asm/kvm.h1
-rw-r--r--arch/loongarch/include/uapi/asm/kvm_para.h1
-rw-r--r--arch/loongarch/kernel/paravirt.c21
-rw-r--r--arch/loongarch/kvm/exit.c21
-rw-r--r--arch/loongarch/kvm/intc/eiointc.c43
-rw-r--r--arch/loongarch/kvm/intc/ipi.c26
-rw-r--r--arch/loongarch/kvm/intc/pch_pic.c31
-rw-r--r--arch/loongarch/kvm/interrupt.c4
-rw-r--r--arch/loongarch/kvm/main.c8
-rw-r--r--arch/loongarch/kvm/vcpu.c125
-rw-r--r--arch/loongarch/kvm/vm.c39
-rw-r--r--tools/testing/selftests/kvm/Makefile.kvm1
-rw-r--r--tools/testing/selftests/kvm/steal_time.c96
17 files changed, 319 insertions, 116 deletions
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index e4fe5b8e8149..19eb5e5c3984 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -37,6 +37,7 @@
#define KVM_REQ_TLB_FLUSH_GPA KVM_ARCH_REQ(0)
#define KVM_REQ_STEAL_UPDATE KVM_ARCH_REQ(1)
#define KVM_REQ_PMU KVM_ARCH_REQ(2)
+#define KVM_REQ_AUX_LOAD KVM_ARCH_REQ(3)
#define KVM_GUESTDBG_SW_BP_MASK \
(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)
@@ -164,6 +165,7 @@ enum emulation_result {
#define LOONGARCH_PV_FEAT_UPDATED BIT_ULL(63)
#define LOONGARCH_PV_FEAT_MASK (BIT(KVM_FEATURE_IPI) | \
+ BIT(KVM_FEATURE_PREEMPT) | \
BIT(KVM_FEATURE_STEAL_TIME) | \
BIT(KVM_FEATURE_USER_HCALL) | \
BIT(KVM_FEATURE_VIRT_EXTIOI))
@@ -200,6 +202,7 @@ struct kvm_vcpu_arch {
/* Which auxiliary state is loaded (KVM_LARCH_*) */
unsigned int aux_inuse;
+ unsigned int aux_ldtype;
/* FPU state */
struct loongarch_fpu fpu FPU_ALIGN;
@@ -252,6 +255,7 @@ struct kvm_vcpu_arch {
u64 guest_addr;
u64 last_steal;
struct gfn_to_hva_cache cache;
+ u8 preempted;
} st;
};
@@ -265,6 +269,11 @@ static inline void writel_sw_gcsr(struct loongarch_csrs *csr, int reg, unsigned
csr->csrs[reg] = val;
}
+static inline bool kvm_guest_has_msgint(struct kvm_vcpu_arch *arch)
+{
+ return arch->cpucfg[1] & CPUCFG1_MSGINT;
+}
+
static inline bool kvm_guest_has_fpu(struct kvm_vcpu_arch *arch)
{
return arch->cpucfg[2] & CPUCFG2_FP;
diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index 3e4b397f423f..fb17ba0fa101 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -37,8 +37,10 @@ struct kvm_steal_time {
__u64 steal;
__u32 version;
__u32 flags;
- __u32 pad[12];
+ __u8 preempted;
+ __u8 pad[47];
};
+#define KVM_VCPU_PREEMPTED (1 << 0)
/*
* Hypercall interface for KVM hypervisor
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index 553c4dc7a156..2a6bc99177d8 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -690,6 +690,7 @@
#define LOONGARCH_CSR_ISR3 0xa3
#define LOONGARCH_CSR_IRR 0xa4
+#define LOONGARCH_CSR_IPR 0xa5
#define LOONGARCH_CSR_PRID 0xc0
diff --git a/arch/loongarch/include/asm/qspinlock.h b/arch/loongarch/include/asm/qspinlock.h
index e76d3aa1e1eb..66244801db67 100644
--- a/arch/loongarch/include/asm/qspinlock.h
+++ b/arch/loongarch/include/asm/qspinlock.h
@@ -34,6 +34,10 @@ __retry:
return true;
}
+#define vcpu_is_preempted vcpu_is_preempted
+
+bool vcpu_is_preempted(int cpu);
+
#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>
diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
index de6c3f18e40a..419647aacdf3 100644
--- a/arch/loongarch/include/uapi/asm/kvm.h
+++ b/arch/loongarch/include/uapi/asm/kvm.h
@@ -105,6 +105,7 @@ struct kvm_fpu {
#define KVM_LOONGARCH_VM_FEAT_PV_STEALTIME 7
#define KVM_LOONGARCH_VM_FEAT_PTW 8
#define KVM_LOONGARCH_VM_FEAT_MSGINT 9
+#define KVM_LOONGARCH_VM_FEAT_PV_PREEMPT 10
/* Device Control API on vcpu fd */
#define KVM_LOONGARCH_VCPU_CPUCFG 0
diff --git a/arch/loongarch/include/uapi/asm/kvm_para.h b/arch/loongarch/include/uapi/asm/kvm_para.h
index 76d802ef01ce..d28cbcadd276 100644
--- a/arch/loongarch/include/uapi/asm/kvm_para.h
+++ b/arch/loongarch/include/uapi/asm/kvm_para.h
@@ -15,6 +15,7 @@
#define CPUCFG_KVM_FEATURE (CPUCFG_KVM_BASE + 4)
#define KVM_FEATURE_IPI 1
#define KVM_FEATURE_STEAL_TIME 2
+#define KVM_FEATURE_PREEMPT 3
/* BIT 24 - 31 are features configurable by user space vmm */
#define KVM_FEATURE_VIRT_EXTIOI 24
#define KVM_FEATURE_USER_HCALL 25
diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
index b1b51f920b23..7f1561906e10 100644
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -12,6 +12,7 @@ static int has_steal_clock;
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
+static DEFINE_STATIC_KEY_FALSE(virt_preempt_key);
DEFINE_STATIC_KEY_FALSE(virt_spin_lock_key);
static u64 native_steal_clock(int cpu)
@@ -267,6 +268,18 @@ static int pv_time_cpu_down_prepare(unsigned int cpu)
return 0;
}
+
+bool vcpu_is_preempted(int cpu)
+{
+ struct kvm_steal_time *src;
+
+ if (!static_branch_unlikely(&virt_preempt_key))
+ return false;
+
+ src = &per_cpu(steal_time, cpu);
+ return !!(src->preempted & KVM_VCPU_PREEMPTED);
+}
+EXPORT_SYMBOL(vcpu_is_preempted);
#endif
static void pv_cpu_reboot(void *unused)
@@ -308,6 +321,9 @@ int __init pv_time_init(void)
pr_err("Failed to install cpu hotplug callbacks\n");
return r;
}
+
+ if (kvm_para_has_feature(KVM_FEATURE_PREEMPT))
+ static_branch_enable(&virt_preempt_key);
#endif
static_call_update(pv_steal_clock, paravt_steal_clock);
@@ -318,7 +334,10 @@ int __init pv_time_init(void)
static_key_slow_inc(&paravirt_steal_rq_enabled);
#endif
- pr_info("Using paravirt steal-time\n");
+ if (static_key_enabled(&virt_preempt_key))
+ pr_info("Using paravirt steal-time with preempt enabled\n");
+ else
+ pr_info("Using paravirt steal-time with preempt disabled\n");
return 0;
}
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index cb493980d874..da0ad89f2eb7 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -754,7 +754,8 @@ static int kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu, int ecode)
return RESUME_HOST;
}
- kvm_own_fpu(vcpu);
+ vcpu->arch.aux_ldtype = KVM_LARCH_FPU;
+ kvm_make_request(KVM_REQ_AUX_LOAD, vcpu);
return RESUME_GUEST;
}
@@ -792,8 +793,12 @@ static long kvm_save_notify(struct kvm_vcpu *vcpu)
*/
static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu, int ecode)
{
- if (kvm_own_lsx(vcpu))
+ if (!kvm_guest_has_lsx(&vcpu->arch))
kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+ else {
+ vcpu->arch.aux_ldtype = KVM_LARCH_LSX;
+ kvm_make_request(KVM_REQ_AUX_LOAD, vcpu);
+ }
return RESUME_GUEST;
}
@@ -808,16 +813,24 @@ static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu, int ecode)
*/
static int kvm_handle_lasx_disabled(struct kvm_vcpu *vcpu, int ecode)
{
- if (kvm_own_lasx(vcpu))
+ if (!kvm_guest_has_lasx(&vcpu->arch))
kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+ else {
+ vcpu->arch.aux_ldtype = KVM_LARCH_LASX;
+ kvm_make_request(KVM_REQ_AUX_LOAD, vcpu);
+ }
return RESUME_GUEST;
}
static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu, int ecode)
{
- if (kvm_own_lbt(vcpu))
+ if (!kvm_guest_has_lbt(&vcpu->arch))
kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+ else {
+ vcpu->arch.aux_ldtype = KVM_LARCH_LBT;
+ kvm_make_request(KVM_REQ_AUX_LOAD, vcpu);
+ }
return RESUME_GUEST;
}
diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
index dfaf6ccfdd8b..e498a3f1e136 100644
--- a/arch/loongarch/kvm/intc/eiointc.c
+++ b/arch/loongarch/kvm/intc/eiointc.c
@@ -119,7 +119,7 @@ void eiointc_set_irq(struct loongarch_eiointc *s, int irq, int level)
static int loongarch_eiointc_read(struct kvm_vcpu *vcpu, struct loongarch_eiointc *s,
gpa_t addr, unsigned long *val)
{
- int index, ret = 0;
+ int index;
u64 data = 0;
gpa_t offset;
@@ -150,40 +150,36 @@ static int loongarch_eiointc_read(struct kvm_vcpu *vcpu, struct loongarch_eioint
data = s->coremap[index];
break;
default:
- ret = -EINVAL;
break;
}
*val = data;
- return ret;
+ return 0;
}
static int kvm_eiointc_read(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, void *val)
{
- int ret = -EINVAL;
unsigned long flags, data, offset;
struct loongarch_eiointc *eiointc = vcpu->kvm->arch.eiointc;
if (!eiointc) {
kvm_err("%s: eiointc irqchip not valid!\n", __func__);
- return -EINVAL;
+ return 0;
}
if (addr & (len - 1)) {
kvm_err("%s: eiointc not aligned addr %llx len %d\n", __func__, addr, len);
- return -EINVAL;
+ return 0;
}
offset = addr & 0x7;
addr -= offset;
vcpu->stat.eiointc_read_exits++;
spin_lock_irqsave(&eiointc->lock, flags);
- ret = loongarch_eiointc_read(vcpu, eiointc, addr, &data);
+ loongarch_eiointc_read(vcpu, eiointc, addr, &data);
spin_unlock_irqrestore(&eiointc->lock, flags);
- if (ret)
- return ret;
data = data >> (offset * 8);
switch (len) {
@@ -208,7 +204,7 @@ static int loongarch_eiointc_write(struct kvm_vcpu *vcpu,
struct loongarch_eiointc *s,
gpa_t addr, u64 value, u64 field_mask)
{
- int index, irq, ret = 0;
+ int index, irq;
u8 cpu;
u64 data, old, mask;
gpa_t offset;
@@ -287,29 +283,27 @@ static int loongarch_eiointc_write(struct kvm_vcpu *vcpu,
eiointc_update_sw_coremap(s, index * 8, data, sizeof(data), true);
break;
default:
- ret = -EINVAL;
break;
}
- return ret;
+ return 0;
}
static int kvm_eiointc_write(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, const void *val)
{
- int ret = -EINVAL;
unsigned long flags, value;
struct loongarch_eiointc *eiointc = vcpu->kvm->arch.eiointc;
if (!eiointc) {
kvm_err("%s: eiointc irqchip not valid!\n", __func__);
- return -EINVAL;
+ return 0;
}
if (addr & (len - 1)) {
kvm_err("%s: eiointc not aligned addr %llx len %d\n", __func__, addr, len);
- return -EINVAL;
+ return 0;
}
vcpu->stat.eiointc_write_exits++;
@@ -317,24 +311,24 @@ static int kvm_eiointc_write(struct kvm_vcpu *vcpu,
switch (len) {
case 1:
value = *(unsigned char *)val;
- ret = loongarch_eiointc_write(vcpu, eiointc, addr, value, 0xFF);
+ loongarch_eiointc_write(vcpu, eiointc, addr, value, 0xFF);
break;
case 2:
value = *(unsigned short *)val;
- ret = loongarch_eiointc_write(vcpu, eiointc, addr, value, USHRT_MAX);
+ loongarch_eiointc_write(vcpu, eiointc, addr, value, USHRT_MAX);
break;
case 4:
value = *(unsigned int *)val;
- ret = loongarch_eiointc_write(vcpu, eiointc, addr, value, UINT_MAX);
+ loongarch_eiointc_write(vcpu, eiointc, addr, value, UINT_MAX);
break;
default:
value = *(unsigned long *)val;
- ret = loongarch_eiointc_write(vcpu, eiointc, addr, value, ULONG_MAX);
+ loongarch_eiointc_write(vcpu, eiointc, addr, value, ULONG_MAX);
break;
}
spin_unlock_irqrestore(&eiointc->lock, flags);
- return ret;
+ return 0;
}
static const struct kvm_io_device_ops kvm_eiointc_ops = {
@@ -352,7 +346,7 @@ static int kvm_eiointc_virt_read(struct kvm_vcpu *vcpu,
if (!eiointc) {
kvm_err("%s: eiointc irqchip not valid!\n", __func__);
- return -EINVAL;
+ return 0;
}
addr -= EIOINTC_VIRT_BASE;
@@ -376,28 +370,25 @@ static int kvm_eiointc_virt_write(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, const void *val)
{
- int ret = 0;
unsigned long flags;
u32 value = *(u32 *)val;
struct loongarch_eiointc *eiointc = vcpu->kvm->arch.eiointc;
if (!eiointc) {
kvm_err("%s: eiointc irqchip not valid!\n", __func__);
- return -EINVAL;
+ return 0;
}
addr -= EIOINTC_VIRT_BASE;
spin_lock_irqsave(&eiointc->lock, flags);
switch (addr) {
case EIOINTC_VIRT_FEATURES:
- ret = -EPERM;
break;
case EIOINTC_VIRT_CONFIG:
/*
* eiointc features can only be set at disabled status
*/
if ((eiointc->status & BIT(EIOINTC_ENABLE)) && value) {
- ret = -EPERM;
break;
}
eiointc->status = value & eiointc->features;
@@ -407,7 +398,7 @@ static int kvm_eiointc_virt_write(struct kvm_vcpu *vcpu,
}
spin_unlock_irqrestore(&eiointc->lock, flags);
- return ret;
+ return 0;
}
static const struct kvm_io_device_ops kvm_eiointc_virt_ops = {
diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c
index 1058c13dba7f..6a044a74c095 100644
--- a/arch/loongarch/kvm/intc/ipi.c
+++ b/arch/loongarch/kvm/intc/ipi.c
@@ -111,7 +111,7 @@ static int mail_send(struct kvm *kvm, uint64_t data)
vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
if (unlikely(vcpu == NULL)) {
kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
- return -EINVAL;
+ return 0;
}
mailbox = ((data & 0xffffffff) >> 2) & 0x7;
offset = IOCSR_IPI_BUF_20 + mailbox * 4;
@@ -145,7 +145,7 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data)
srcu_read_unlock(&vcpu->kvm->srcu, idx);
if (unlikely(ret)) {
kvm_err("%s: : read data from addr %llx failed\n", __func__, addr);
- return ret;
+ return 0;
}
/* Construct the mask by scanning the bit 27-30 */
for (i = 0; i < 4; i++) {
@@ -162,7 +162,7 @@ static int send_ipi_data(struct kvm_vcpu *vcpu, gpa_t addr, uint64_t data)
if (unlikely(ret))
kvm_err("%s: : write data to addr %llx failed\n", __func__, addr);
- return ret;
+ return 0;
}
static int any_send(struct kvm *kvm, uint64_t data)
@@ -174,7 +174,7 @@ static int any_send(struct kvm *kvm, uint64_t data)
vcpu = kvm_get_vcpu_by_cpuid(kvm, cpu);
if (unlikely(vcpu == NULL)) {
kvm_err("%s: invalid target cpu: %d\n", __func__, cpu);
- return -EINVAL;
+ return 0;
}
offset = data & 0xffff;
@@ -183,7 +183,6 @@ static int any_send(struct kvm *kvm, uint64_t data)
static int loongarch_ipi_readl(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *val)
{
- int ret = 0;
uint32_t offset;
uint64_t res = 0;
@@ -202,33 +201,27 @@ static int loongarch_ipi_readl(struct kvm_vcpu *vcpu, gpa_t addr, int len, void
spin_unlock(&vcpu->arch.ipi_state.lock);
break;
case IOCSR_IPI_SET:
- res = 0;
- break;
case IOCSR_IPI_CLEAR:
- res = 0;
break;
case IOCSR_IPI_BUF_20 ... IOCSR_IPI_BUF_38 + 7:
if (offset + len > IOCSR_IPI_BUF_38 + 8) {
kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
__func__, offset, len);
- ret = -EINVAL;
break;
}
res = read_mailbox(vcpu, offset, len);
break;
default:
kvm_err("%s: unknown addr: %llx\n", __func__, addr);
- ret = -EINVAL;
break;
}
*(uint64_t *)val = res;
- return ret;
+ return 0;
}
static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr, int len, const void *val)
{
- int ret = 0;
uint64_t data;
uint32_t offset;
@@ -239,7 +232,6 @@ static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr, int len, cons
switch (offset) {
case IOCSR_IPI_STATUS:
- ret = -EINVAL;
break;
case IOCSR_IPI_EN:
spin_lock(&vcpu->arch.ipi_state.lock);
@@ -257,7 +249,6 @@ static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr, int len, cons
if (offset + len > IOCSR_IPI_BUF_38 + 8) {
kvm_err("%s: invalid offset or len: offset = %d, len = %d\n",
__func__, offset, len);
- ret = -EINVAL;
break;
}
write_mailbox(vcpu, offset, data, len);
@@ -266,18 +257,17 @@ static int loongarch_ipi_writel(struct kvm_vcpu *vcpu, gpa_t addr, int len, cons
ipi_send(vcpu->kvm, data);
break;
case IOCSR_MAIL_SEND:
- ret = mail_send(vcpu->kvm, data);
+ mail_send(vcpu->kvm, data);
break;
case IOCSR_ANY_SEND:
- ret = any_send(vcpu->kvm, data);
+ any_send(vcpu->kvm, data);
break;
default:
kvm_err("%s: unknown addr: %llx\n", __func__, addr);
- ret = -EINVAL;
break;
}
- return ret;
+ return 0;
}
static int kvm_ipi_read(struct kvm_vcpu *vcpu,
diff --git a/arch/loongarch/kvm/intc/pch_pic.c b/arch/loongarch/kvm/intc/pch_pic.c
index 4addb34bf432..a175f52fcf7f 100644
--- a/arch/loongarch/kvm/intc/pch_pic.c
+++ b/arch/loongarch/kvm/intc/pch_pic.c
@@ -74,7 +74,7 @@ void pch_msi_set_irq(struct kvm *kvm, int irq, int level)
static int loongarch_pch_pic_read(struct loongarch_pch_pic *s, gpa_t addr, int len, void *val)
{
- int ret = 0, offset;
+ int offset;
u64 data = 0;
void *ptemp;
@@ -121,34 +121,32 @@ static int loongarch_pch_pic_read(struct loongarch_pch_pic *s, gpa_t addr, int l
data = s->isr;
break;
default:
- ret = -EINVAL;
+ break;
}
spin_unlock(&s->lock);
- if (ret == 0) {
- offset = (addr - s->pch_pic_base) & 7;
- data = data >> (offset * 8);
- memcpy(val, &data, len);
- }
+ offset = (addr - s->pch_pic_base) & 7;
+ data = data >> (offset * 8);
+ memcpy(val, &data, len);
- return ret;
+ return 0;
}
static int kvm_pch_pic_read(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, void *val)
{
- int ret;
+ int ret = 0;
struct loongarch_pch_pic *s = vcpu->kvm->arch.pch_pic;
if (!s) {
kvm_err("%s: pch pic irqchip not valid!\n", __func__);
- return -EINVAL;
+ return ret;
}
if (addr & (len - 1)) {
kvm_err("%s: pch pic not aligned addr %llx len %d\n", __func__, addr, len);
- return -EINVAL;
+ return ret;
}
/* statistics of pch pic reading */
@@ -161,7 +159,7 @@ static int kvm_pch_pic_read(struct kvm_vcpu *vcpu,
static int loongarch_pch_pic_write(struct loongarch_pch_pic *s, gpa_t addr,
int len, const void *val)
{
- int ret = 0, offset;
+ int offset;
u64 old, data, mask;
void *ptemp;
@@ -226,29 +224,28 @@ static int loongarch_pch_pic_write(struct loongarch_pch_pic *s, gpa_t addr,
case PCH_PIC_ROUTE_ENTRY_START ... PCH_PIC_ROUTE_ENTRY_END:
break;
default:
- ret = -EINVAL;
break;
}
spin_unlock(&s->lock);
- return ret;
+ return 0;
}
static int kvm_pch_pic_write(struct kvm_vcpu *vcpu,
struct kvm_io_device *dev,
gpa_t addr, int len, const void *val)
{
- int ret;
+ int ret = 0;
struct loongarch_pch_pic *s = vcpu->kvm->arch.pch_pic;
if (!s) {
kvm_err("%s: pch pic irqchip not valid!\n", __func__);
- return -EINVAL;
+ return ret;
}
if (addr & (len - 1)) {
kvm_err("%s: pch pic not aligned addr %llx len %d\n", __func__, addr, len);
- return -EINVAL;
+ return ret;
}
/* statistics of pch pic writing */
diff --git a/arch/loongarch/kvm/interrupt.c b/arch/loongarch/kvm/interrupt.c
index a6d42d399a59..fb704f4c8ac5 100644
--- a/arch/loongarch/kvm/interrupt.c
+++ b/arch/loongarch/kvm/interrupt.c
@@ -32,7 +32,7 @@ static int kvm_irq_deliver(struct kvm_vcpu *vcpu, unsigned int priority)
if (priority < EXCCODE_INT_NUM)
irq = priority_to_irq[priority];
- if (cpu_has_msgint && (priority == INT_AVEC)) {
+ if (kvm_guest_has_msgint(&vcpu->arch) && (priority == INT_AVEC)) {
set_gcsr_estat(irq);
return 1;
}
@@ -64,7 +64,7 @@ static int kvm_irq_clear(struct kvm_vcpu *vcpu, unsigned int priority)
if (priority < EXCCODE_INT_NUM)
irq = priority_to_irq[priority];
- if (cpu_has_msgint && (priority == INT_AVEC)) {
+ if (kvm_guest_has_msgint(&vcpu->arch) && (priority == INT_AVEC)) {
clear_gcsr_estat(irq);
return 1;
}
diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
index 80ea63d465b8..d1c5156e02d8 100644
--- a/arch/loongarch/kvm/main.c
+++ b/arch/loongarch/kvm/main.c
@@ -192,6 +192,14 @@ static void kvm_init_gcsr_flag(void)
set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR2);
set_gcsr_sw_flag(LOONGARCH_CSR_PERFCTRL3);
set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR3);
+
+ if (cpu_has_msgint) {
+ set_gcsr_hw_flag(LOONGARCH_CSR_IPR);
+ set_gcsr_hw_flag(LOONGARCH_CSR_ISR0);
+ set_gcsr_hw_flag(LOONGARCH_CSR_ISR1);
+ set_gcsr_hw_flag(LOONGARCH_CSR_ISR2);
+ set_gcsr_hw_flag(LOONGARCH_CSR_ISR3);
+ }
}
static void kvm_update_vpid(struct kvm_vcpu *vcpu, int cpu)
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 656b954c1134..550c0d05666a 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -181,6 +181,11 @@ static void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
}
st = (struct kvm_steal_time __user *)ghc->hva;
+ if (kvm_guest_has_pv_feature(vcpu, KVM_FEATURE_PREEMPT)) {
+ unsafe_put_user(0, &st->preempted, out);
+ vcpu->arch.st.preempted = 0;
+ }
+
unsafe_get_user(version, &st->version, out);
if (version & 1)
version += 1; /* first time write, random junk */
@@ -232,6 +237,27 @@ static void kvm_late_check_requests(struct kvm_vcpu *vcpu)
kvm_flush_tlb_gpa(vcpu, vcpu->arch.flush_gpa);
vcpu->arch.flush_gpa = INVALID_GPA;
}
+
+ if (kvm_check_request(KVM_REQ_AUX_LOAD, vcpu)) {
+ switch (vcpu->arch.aux_ldtype) {
+ case KVM_LARCH_FPU:
+ kvm_own_fpu(vcpu);
+ break;
+ case KVM_LARCH_LSX:
+ kvm_own_lsx(vcpu);
+ break;
+ case KVM_LARCH_LASX:
+ kvm_own_lasx(vcpu);
+ break;
+ case KVM_LARCH_LBT:
+ kvm_own_lbt(vcpu);
+ break;
+ default:
+ break;
+ }
+
+ vcpu->arch.aux_ldtype = 0;
+ }
}
/*
@@ -652,6 +678,8 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
static int _kvm_get_cpucfg_mask(int id, u64 *v)
{
+ unsigned int config;
+
if (id < 0 || id >= KVM_MAX_CPUCFG_REGS)
return -EINVAL;
@@ -684,9 +712,17 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v)
if (cpu_has_ptw)
*v |= CPUCFG2_PTW;
+ config = read_cpucfg(LOONGARCH_CPUCFG2);
+ *v |= config & (CPUCFG2_FRECIPE | CPUCFG2_DIV32 | CPUCFG2_LAM_BH);
+ *v |= config & (CPUCFG2_LAMCAS | CPUCFG2_LLACQ_SCREL | CPUCFG2_SCQ);
return 0;
case LOONGARCH_CPUCFG3:
- *v = GENMASK(16, 0);
+ *v = GENMASK(23, 0);
+
+ /* VM does not support memory order and SFB setting */
+ config = read_cpucfg(LOONGARCH_CPUCFG3);
+ *v &= config & ~(CPUCFG3_SFB);
+ *v &= config & ~(CPUCFG3_ALDORDER_CAP | CPUCFG3_ASTORDER_CAP | CPUCFG3_SLDORDER_CAP);
return 0;
case LOONGARCH_CPUCFG4:
case LOONGARCH_CPUCFG5:
@@ -717,6 +753,7 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v)
static int kvm_check_cpucfg(int id, u64 val)
{
int ret;
+ u32 host;
u64 mask = 0;
ret = _kvm_get_cpucfg_mask(id, &mask);
@@ -746,9 +783,16 @@ static int kvm_check_cpucfg(int id, u64 val)
/* LASX architecturally implies LSX and FP but val does not satisfy that */
return -EINVAL;
return 0;
+ case LOONGARCH_CPUCFG3:
+ host = read_cpucfg(LOONGARCH_CPUCFG3);
+ if ((val & CPUCFG3_RVAMAX) > (host & CPUCFG3_RVAMAX))
+ return -EINVAL;
+ if ((val & CPUCFG3_SPW_LVL) > (host & CPUCFG3_SPW_LVL))
+ return -EINVAL;
+ return 0;
case LOONGARCH_CPUCFG6:
if (val & CPUCFG6_PMP) {
- u32 host = read_cpucfg(LOONGARCH_CPUCFG6);
+ host = read_cpucfg(LOONGARCH_CPUCFG6);
if ((val & CPUCFG6_PMBITS) != (host & CPUCFG6_PMBITS))
return -EINVAL;
if ((val & CPUCFG6_PMNUM) > (host & CPUCFG6_PMNUM))
@@ -1286,16 +1330,11 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
#ifdef CONFIG_CPU_HAS_LBT
int kvm_own_lbt(struct kvm_vcpu *vcpu)
{
- if (!kvm_guest_has_lbt(&vcpu->arch))
- return -EINVAL;
-
- preempt_disable();
if (!(vcpu->arch.aux_inuse & KVM_LARCH_LBT)) {
set_csr_euen(CSR_EUEN_LBTEN);
_restore_lbt(&vcpu->arch.lbt);
vcpu->arch.aux_inuse |= KVM_LARCH_LBT;
}
- preempt_enable();
return 0;
}
@@ -1338,8 +1377,6 @@ static inline void kvm_check_fcsr_alive(struct kvm_vcpu *vcpu) { }
/* Enable FPU and restore context */
void kvm_own_fpu(struct kvm_vcpu *vcpu)
{
- preempt_disable();
-
/*
* Enable FPU for guest
* Set FR and FRE according to guest context
@@ -1350,19 +1387,12 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
kvm_restore_fpu(&vcpu->arch.fpu);
vcpu->arch.aux_inuse |= KVM_LARCH_FPU;
trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_FPU);
-
- preempt_enable();
}
#ifdef CONFIG_CPU_HAS_LSX
/* Enable LSX and restore context */
int kvm_own_lsx(struct kvm_vcpu *vcpu)
{
- if (!kvm_guest_has_fpu(&vcpu->arch) || !kvm_guest_has_lsx(&vcpu->arch))
- return -EINVAL;
-
- preempt_disable();
-
/* Enable LSX for guest */
kvm_check_fcsr(vcpu, vcpu->arch.fpu.fcsr);
set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
@@ -1384,7 +1414,6 @@ int kvm_own_lsx(struct kvm_vcpu *vcpu)
trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
- preempt_enable();
return 0;
}
@@ -1394,11 +1423,6 @@ int kvm_own_lsx(struct kvm_vcpu *vcpu)
/* Enable LASX and restore context */
int kvm_own_lasx(struct kvm_vcpu *vcpu)
{
- if (!kvm_guest_has_fpu(&vcpu->arch) || !kvm_guest_has_lsx(&vcpu->arch) || !kvm_guest_has_lasx(&vcpu->arch))
- return -EINVAL;
-
- preempt_disable();
-
kvm_check_fcsr(vcpu, vcpu->arch.fpu.fcsr);
set_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN | CSR_EUEN_LASXEN);
switch (vcpu->arch.aux_inuse & (KVM_LARCH_FPU | KVM_LARCH_LSX)) {
@@ -1420,7 +1444,6 @@ int kvm_own_lasx(struct kvm_vcpu *vcpu)
trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LASX);
vcpu->arch.aux_inuse |= KVM_LARCH_LASX | KVM_LARCH_LSX | KVM_LARCH_FPU;
- preempt_enable();
return 0;
}
@@ -1661,7 +1684,9 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_DMWIN2);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_DMWIN3);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_LLBCTL);
- if (cpu_has_msgint) {
+
+ if (kvm_guest_has_msgint(&vcpu->arch)) {
+ kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_IPR);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR0);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR1);
kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR2);
@@ -1756,7 +1781,9 @@ static int _kvm_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN1);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN2);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN3);
- if (cpu_has_msgint) {
+
+ if (kvm_guest_has_msgint(&vcpu->arch)) {
+ kvm_save_hw_gcsr(csr, LOONGARCH_CSR_IPR);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR0);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR1);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR2);
@@ -1773,11 +1800,57 @@ out:
return 0;
}
+static void kvm_vcpu_set_pv_preempted(struct kvm_vcpu *vcpu)
+{
+ gpa_t gpa;
+ struct gfn_to_hva_cache *ghc;
+ struct kvm_memslots *slots;
+ struct kvm_steal_time __user *st;
+
+ gpa = vcpu->arch.st.guest_addr;
+ if (!(gpa & KVM_STEAL_PHYS_VALID))
+ return;
+
+ /* vCPU may be preempted for many times */
+ if (vcpu->arch.st.preempted)
+ return;
+
+ /* This happens on process exit */
+ if (unlikely(current->mm != vcpu->kvm->mm))
+ return;
+
+ gpa &= KVM_STEAL_PHYS_MASK;
+ ghc = &vcpu->arch.st.cache;
+ slots = kvm_memslots(vcpu->kvm);
+ if (slots->generation != ghc->generation || gpa != ghc->gpa) {
+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, gpa, sizeof(*st))) {
+ ghc->gpa = INVALID_GPA;
+ return;
+ }
+ }
+
+ st = (struct kvm_steal_time __user *)ghc->hva;
+ unsafe_put_user(KVM_VCPU_PREEMPTED, &st->preempted, out);
+ vcpu->arch.st.preempted = KVM_VCPU_PREEMPTED;
+out:
+ mark_page_dirty_in_slot(vcpu->kvm, ghc->memslot, gpa_to_gfn(ghc->gpa));
+}
+
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
- int cpu;
+ int cpu, idx;
unsigned long flags;
+ if (vcpu->preempted && kvm_guest_has_pv_feature(vcpu, KVM_FEATURE_PREEMPT)) {
+ /*
+ * Take the srcu lock as memslots will be accessed to check
+ * the gfn cache generation against the memslots generation.
+ */
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+ kvm_vcpu_set_pv_preempted(vcpu);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ }
+
local_irq_save(flags);
cpu = smp_processor_id();
vcpu->arch.last_sched_cpu = cpu;
diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c
index 194ccbcdc3b3..9681ade890c6 100644
--- a/arch/loongarch/kvm/vm.c
+++ b/arch/loongarch/kvm/vm.c
@@ -29,6 +29,21 @@ static void kvm_vm_init_features(struct kvm *kvm)
{
unsigned long val;
+ if (cpu_has_lsx)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_LSX);
+ if (cpu_has_lasx)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_LASX);
+ if (cpu_has_lbt_x86)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_X86BT);
+ if (cpu_has_lbt_arm)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_ARMBT);
+ if (cpu_has_lbt_mips)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_MIPSBT);
+ if (cpu_has_ptw)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PTW);
+ if (cpu_has_msgint)
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_MSGINT);
+
val = read_csr_gcfg();
if (val & CSR_GCFG_GPMP)
kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PMU);
@@ -37,7 +52,9 @@ static void kvm_vm_init_features(struct kvm *kvm)
kvm->arch.pv_features = BIT(KVM_FEATURE_IPI);
kvm->arch.kvm_features = BIT(KVM_LOONGARCH_VM_FEAT_PV_IPI);
if (kvm_pvtime_supported()) {
+ kvm->arch.pv_features |= BIT(KVM_FEATURE_PREEMPT);
kvm->arch.pv_features |= BIT(KVM_FEATURE_STEAL_TIME);
+ kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PV_PREEMPT);
kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PV_STEALTIME);
}
}
@@ -131,35 +148,15 @@ static int kvm_vm_feature_has_attr(struct kvm *kvm, struct kvm_device_attr *attr
{
switch (attr->attr) {
case KVM_LOONGARCH_VM_FEAT_LSX:
- if (cpu_has_lsx)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_LASX:
- if (cpu_has_lasx)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_X86BT:
- if (cpu_has_lbt_x86)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_ARMBT:
- if (cpu_has_lbt_arm)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_MIPSBT:
- if (cpu_has_lbt_mips)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_PTW:
- if (cpu_has_ptw)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_MSGINT:
- if (cpu_has_msgint)
- return 0;
- return -ENXIO;
case KVM_LOONGARCH_VM_FEAT_PMU:
case KVM_LOONGARCH_VM_FEAT_PV_IPI:
+ case KVM_LOONGARCH_VM_FEAT_PV_PREEMPT:
case KVM_LOONGARCH_VM_FEAT_PV_STEALTIME:
if (kvm_vm_support(&kvm->arch, attr->attr))
return 0;
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index d45bf4ccb3bf..af2f4061d273 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -228,6 +228,7 @@ TEST_GEN_PROGS_loongarch += kvm_page_table_test
TEST_GEN_PROGS_loongarch += memslot_modification_stress_test
TEST_GEN_PROGS_loongarch += memslot_perf_test
TEST_GEN_PROGS_loongarch += set_memory_region_test
+TEST_GEN_PROGS_loongarch += steal_time
SPLIT_TESTS += arch_timer
SPLIT_TESTS += get-reg-list
diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index 8edc1fca345b..7be8adfe5dd3 100644
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -301,6 +301,102 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
pr_info("\n");
}
+#elif defined(__loongarch__)
+
+/* steal_time must have 64-byte alignment */
+#define STEAL_TIME_SIZE ((sizeof(struct kvm_steal_time) + 63) & ~63)
+#define KVM_STEAL_PHYS_VALID BIT_ULL(0)
+
+struct kvm_steal_time {
+ __u64 steal;
+ __u32 version;
+ __u32 flags;
+ __u8 preempted;
+ __u8 pad[47];
+};
+
+static void check_status(struct kvm_steal_time *st)
+{
+ GUEST_ASSERT(!(READ_ONCE(st->version) & 1));
+ GUEST_ASSERT_EQ(READ_ONCE(st->flags), 0);
+ GUEST_ASSERT_EQ(READ_ONCE(st->preempted), 0);
+}
+
+static void guest_code(int cpu)
+{
+ uint32_t version;
+ struct kvm_steal_time *st = st_gva[cpu];
+
+ memset(st, 0, sizeof(*st));
+ GUEST_SYNC(0);
+
+ check_status(st);
+ WRITE_ONCE(guest_stolen_time[cpu], st->steal);
+ version = READ_ONCE(st->version);
+ check_status(st);
+ GUEST_SYNC(1);
+
+ check_status(st);
+ GUEST_ASSERT(version < READ_ONCE(st->version));
+ WRITE_ONCE(guest_stolen_time[cpu], st->steal);
+ check_status(st);
+ GUEST_DONE();
+}
+
+static bool is_steal_time_supported(struct kvm_vcpu *vcpu)
+{
+ int err;
+ uint64_t val;
+ struct kvm_device_attr attr = {
+ .group = KVM_LOONGARCH_VCPU_CPUCFG,
+ .attr = CPUCFG_KVM_FEATURE,
+ .addr = (uint64_t)&val,
+ };
+
+ err = __vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &attr);
+ if (err)
+ return false;
+
+ err = __vcpu_ioctl(vcpu, KVM_GET_DEVICE_ATTR, &attr);
+ if (err)
+ return false;
+
+ return val & BIT(KVM_FEATURE_STEAL_TIME);
+}
+
+static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i)
+{
+ int err;
+ uint64_t st_gpa;
+ struct kvm_vm *vm = vcpu->vm;
+ struct kvm_device_attr attr = {
+ .group = KVM_LOONGARCH_VCPU_PVTIME_CTRL,
+ .attr = KVM_LOONGARCH_VCPU_PVTIME_GPA,
+ .addr = (uint64_t)&st_gpa,
+ };
+
+ /* ST_GPA_BASE is identity mapped */
+ st_gva[i] = (void *)(ST_GPA_BASE + i * STEAL_TIME_SIZE);
+ sync_global_to_guest(vm, st_gva[i]);
+
+ err = __vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &attr);
+ TEST_ASSERT(err == 0, "No PV stealtime Feature");
+
+ st_gpa = (unsigned long)st_gva[i] | KVM_STEAL_PHYS_VALID;
+ err = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &attr);
+ TEST_ASSERT(err == 0, "Fail to set PV stealtime GPA");
+}
+
+static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
+{
+ struct kvm_steal_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]);
+
+ ksft_print_msg("VCPU%d:\n", vcpu_idx);
+ ksft_print_msg(" steal: %lld\n", st->steal);
+ ksft_print_msg(" flags: %d\n", st->flags);
+ ksft_print_msg(" version: %d\n", st->version);
+ ksft_print_msg(" preempted: %d\n", st->preempted);
+}
#endif
static void *do_steal_time(void *arg)