summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--Documentation/virtual/kvm/devices/vm.txt3
-rw-r--r--arch/s390/include/asm/cpacf.h1
-rw-r--r--arch/s390/include/asm/kvm_host.h2
-rw-r--r--arch/s390/include/uapi/asm/kvm.h5
-rw-r--r--arch/s390/kvm/Kconfig1
-rw-r--r--arch/s390/kvm/interrupt.c11
-rw-r--r--arch/s390/kvm/kvm-s390.c117
-rw-r--r--arch/s390/kvm/vsie.c13
-rw-r--r--arch/s390/tools/gen_facilities.c3
-rw-r--r--include/linux/kvm_host.h10
-rw-r--r--tools/arch/s390/include/uapi/asm/kvm.h3
-rw-r--r--virt/kvm/Kconfig3
-rw-r--r--virt/kvm/kvm_main.c2
13 files changed, 163 insertions, 11 deletions
diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt
index 95ca68d663a4..4ffb82b02468 100644
--- a/Documentation/virtual/kvm/devices/vm.txt
+++ b/Documentation/virtual/kvm/devices/vm.txt
@@ -141,7 +141,8 @@ struct kvm_s390_vm_cpu_subfunc {
u8 pcc[16]; # valid with Message-Security-Assist-Extension 4
u8 ppno[16]; # valid with Message-Security-Assist-Extension 5
u8 kma[16]; # valid with Message-Security-Assist-Extension 8
- u8 reserved[1808]; # reserved for future instructions
+ u8 kdsa[16]; # valid with Message-Security-Assist-Extension 9
+ u8 reserved[1792]; # reserved for future instructions
};
Parameters: address of a buffer to load the subfunction blocks from.
diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/cpacf.h
index 3cc52e37b4b2..ce2770743cc5 100644
--- a/arch/s390/include/asm/cpacf.h
+++ b/arch/s390/include/asm/cpacf.h
@@ -28,6 +28,7 @@
#define CPACF_KMCTR 0xb92d /* MSA4 */
#define CPACF_PRNO 0xb93c /* MSA5 */
#define CPACF_KMA 0xb929 /* MSA8 */
+#define CPACF_KDSA 0xb93a /* MSA9 */
/*
* En/decryption modifier bits
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index c47e22bba87f..bdbc81b5bc91 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -278,6 +278,7 @@ struct kvm_s390_sie_block {
#define ECD_HOSTREGMGMT 0x20000000
#define ECD_MEF 0x08000000
#define ECD_ETOKENF 0x02000000
+#define ECD_ECC 0x00200000
__u32 ecd; /* 0x01c8 */
__u8 reserved1cc[18]; /* 0x01cc */
__u64 pp; /* 0x01de */
@@ -312,6 +313,7 @@ struct kvm_vcpu_stat {
u64 halt_successful_poll;
u64 halt_attempted_poll;
u64 halt_poll_invalid;
+ u64 halt_no_poll_steal;
u64 halt_wakeup;
u64 instruction_lctl;
u64 instruction_lctlg;
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index 16511d97e8dc..47104e5b47fd 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -152,7 +152,10 @@ struct kvm_s390_vm_cpu_subfunc {
__u8 pcc[16]; /* with MSA4 */
__u8 ppno[16]; /* with MSA5 */
__u8 kma[16]; /* with MSA8 */
- __u8 reserved[1808];
+ __u8 kdsa[16]; /* with MSA9 */
+ __u8 sortl[32]; /* with STFLE.150 */
+ __u8 dfltcc[32]; /* with STFLE.151 */
+ __u8 reserved[1728];
};
/* kvm attributes for crypto */
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 767453faacfc..e987e73738b5 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -31,6 +31,7 @@ config KVM
select HAVE_KVM_IRQFD
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_INVALID_WAKEUPS
+ select HAVE_KVM_NO_POLL
select SRCU
select KVM_VFIO
---help---
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 82162867f378..bfd55ad34a3e 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -14,6 +14,7 @@
#include <linux/kvm_host.h>
#include <linux/hrtimer.h>
#include <linux/mmu_context.h>
+#include <linux/nospec.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <linux/bitmap.h>
@@ -2307,6 +2308,7 @@ static struct s390_io_adapter *get_io_adapter(struct kvm *kvm, unsigned int id)
{
if (id >= MAX_S390_IO_ADAPTERS)
return NULL;
+ id = array_index_nospec(id, MAX_S390_IO_ADAPTERS);
return kvm->arch.adapters[id];
}
@@ -2320,8 +2322,13 @@ static int register_io_adapter(struct kvm_device *dev,
(void __user *)attr->addr, sizeof(adapter_info)))
return -EFAULT;
- if ((adapter_info.id >= MAX_S390_IO_ADAPTERS) ||
- (dev->kvm->arch.adapters[adapter_info.id] != NULL))
+ if (adapter_info.id >= MAX_S390_IO_ADAPTERS)
+ return -EINVAL;
+
+ adapter_info.id = array_index_nospec(adapter_info.id,
+ MAX_S390_IO_ADAPTERS);
+
+ if (dev->kvm->arch.adapters[adapter_info.id] != NULL)
return -EINVAL;
adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 28f35d2b06cb..8d6d75db8de6 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -75,6 +75,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "halt_successful_poll", VCPU_STAT(halt_successful_poll) },
{ "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) },
{ "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) },
+ { "halt_no_poll_steal", VCPU_STAT(halt_no_poll_steal) },
{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
{ "instruction_lctlg", VCPU_STAT(instruction_lctlg) },
{ "instruction_lctl", VCPU_STAT(instruction_lctl) },
@@ -177,6 +178,11 @@ static int hpage;
module_param(hpage, int, 0444);
MODULE_PARM_DESC(hpage, "1m huge page backing support");
+/* maximum percentage of steal time for polling. >100 is treated like 100 */
+static u8 halt_poll_max_steal = 10;
+module_param(halt_poll_max_steal, byte, 0644);
+MODULE_PARM_DESC(hpage, "Maximum percentage of steal time to allow polling");
+
/*
* For now we handle at most 16 double words as this is what the s390 base
* kernel handles and stores in the prefix page. If we ever need to go beyond
@@ -321,6 +327,22 @@ static inline int plo_test_bit(unsigned char nr)
return cc == 0;
}
+static inline void __insn32_query(unsigned int opcode, u8 query[32])
+{
+ register unsigned long r0 asm("0") = 0; /* query function */
+ register unsigned long r1 asm("1") = (unsigned long) query;
+
+ asm volatile(
+ /* Parameter regs are ignored */
+ " .insn rrf,%[opc] << 16,2,4,6,0\n"
+ : "=m" (*query)
+ : "d" (r0), "a" (r1), [opc] "i" (opcode)
+ : "cc");
+}
+
+#define INSN_SORTL 0xb938
+#define INSN_DFLTCC 0xb939
+
static void kvm_s390_cpu_feat_init(void)
{
int i;
@@ -368,6 +390,16 @@ static void kvm_s390_cpu_feat_init(void)
__cpacf_query(CPACF_KMA, (cpacf_mask_t *)
kvm_s390_available_subfunc.kma);
+ if (test_facility(155)) /* MSA9 */
+ __cpacf_query(CPACF_KDSA, (cpacf_mask_t *)
+ kvm_s390_available_subfunc.kdsa);
+
+ if (test_facility(150)) /* SORTL */
+ __insn32_query(INSN_SORTL, kvm_s390_available_subfunc.sortl);
+
+ if (test_facility(151)) /* DFLTCC */
+ __insn32_query(INSN_DFLTCC, kvm_s390_available_subfunc.dfltcc);
+
if (MACHINE_HAS_ESOP)
allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP);
/*
@@ -654,6 +686,14 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
set_kvm_facility(kvm->arch.model.fac_mask, 135);
set_kvm_facility(kvm->arch.model.fac_list, 135);
}
+ if (test_facility(148)) {
+ set_kvm_facility(kvm->arch.model.fac_mask, 148);
+ set_kvm_facility(kvm->arch.model.fac_list, 148);
+ }
+ if (test_facility(152)) {
+ set_kvm_facility(kvm->arch.model.fac_mask, 152);
+ set_kvm_facility(kvm->arch.model.fac_list, 152);
+ }
r = 0;
} else
r = -EINVAL;
@@ -1320,6 +1360,19 @@ static int kvm_s390_set_processor_subfunc(struct kvm *kvm,
VM_EVENT(kvm, 3, "SET: guest KMA subfunc 0x%16.16lx.%16.16lx",
((unsigned long *) &kvm->arch.model.subfuncs.kma)[0],
((unsigned long *) &kvm->arch.model.subfuncs.kma)[1]);
+ VM_EVENT(kvm, 3, "SET: guest KDSA subfunc 0x%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.kdsa)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.kdsa)[1]);
+ VM_EVENT(kvm, 3, "SET: guest SORTL subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[1],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[2],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[3]);
+ VM_EVENT(kvm, 3, "SET: guest DFLTCC subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[1],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[2],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[3]);
return 0;
}
@@ -1488,6 +1541,19 @@ static int kvm_s390_get_processor_subfunc(struct kvm *kvm,
VM_EVENT(kvm, 3, "GET: guest KMA subfunc 0x%16.16lx.%16.16lx",
((unsigned long *) &kvm->arch.model.subfuncs.kma)[0],
((unsigned long *) &kvm->arch.model.subfuncs.kma)[1]);
+ VM_EVENT(kvm, 3, "GET: guest KDSA subfunc 0x%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.kdsa)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.kdsa)[1]);
+ VM_EVENT(kvm, 3, "GET: guest SORTL subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[1],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[2],
+ ((unsigned long *) &kvm->arch.model.subfuncs.sortl)[3]);
+ VM_EVENT(kvm, 3, "GET: guest DFLTCC subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[0],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[1],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[2],
+ ((unsigned long *) &kvm->arch.model.subfuncs.dfltcc)[3]);
return 0;
}
@@ -1543,6 +1609,19 @@ static int kvm_s390_get_machine_subfunc(struct kvm *kvm,
VM_EVENT(kvm, 3, "GET: host KMA subfunc 0x%16.16lx.%16.16lx",
((unsigned long *) &kvm_s390_available_subfunc.kma)[0],
((unsigned long *) &kvm_s390_available_subfunc.kma)[1]);
+ VM_EVENT(kvm, 3, "GET: host KDSA subfunc 0x%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm_s390_available_subfunc.kdsa)[0],
+ ((unsigned long *) &kvm_s390_available_subfunc.kdsa)[1]);
+ VM_EVENT(kvm, 3, "GET: host SORTL subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm_s390_available_subfunc.sortl)[0],
+ ((unsigned long *) &kvm_s390_available_subfunc.sortl)[1],
+ ((unsigned long *) &kvm_s390_available_subfunc.sortl)[2],
+ ((unsigned long *) &kvm_s390_available_subfunc.sortl)[3]);
+ VM_EVENT(kvm, 3, "GET: host DFLTCC subfunc 0x%16.16lx.%16.16lx.%16.16lx.%16.16lx",
+ ((unsigned long *) &kvm_s390_available_subfunc.dfltcc)[0],
+ ((unsigned long *) &kvm_s390_available_subfunc.dfltcc)[1],
+ ((unsigned long *) &kvm_s390_available_subfunc.dfltcc)[2],
+ ((unsigned long *) &kvm_s390_available_subfunc.dfltcc)[3]);
return 0;
}
@@ -2814,6 +2893,25 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
vcpu->arch.enabled_gmap = vcpu->arch.gmap;
}
+static bool kvm_has_pckmo_subfunc(struct kvm *kvm, unsigned long nr)
+{
+ if (test_bit_inv(nr, (unsigned long *)&kvm->arch.model.subfuncs.pckmo) &&
+ test_bit_inv(nr, (unsigned long *)&kvm_s390_available_subfunc.pckmo))
+ return true;
+ return false;
+}
+
+static bool kvm_has_pckmo_ecc(struct kvm *kvm)
+{
+ /* At least one ECC subfunction must be present */
+ return kvm_has_pckmo_subfunc(kvm, 32) ||
+ kvm_has_pckmo_subfunc(kvm, 33) ||
+ kvm_has_pckmo_subfunc(kvm, 34) ||
+ kvm_has_pckmo_subfunc(kvm, 40) ||
+ kvm_has_pckmo_subfunc(kvm, 41);
+
+}
+
static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
{
/*
@@ -2826,13 +2924,19 @@ static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->crycbd = vcpu->kvm->arch.crypto.crycbd;
vcpu->arch.sie_block->ecb3 &= ~(ECB3_AES | ECB3_DEA);
vcpu->arch.sie_block->eca &= ~ECA_APIE;
+ vcpu->arch.sie_block->ecd &= ~ECD_ECC;
if (vcpu->kvm->arch.crypto.apie)
vcpu->arch.sie_block->eca |= ECA_APIE;
/* Set up protected key support */
- if (vcpu->kvm->arch.crypto.aes_kw)
+ if (vcpu->kvm->arch.crypto.aes_kw) {
vcpu->arch.sie_block->ecb3 |= ECB3_AES;
+ /* ecc is also wrapped with AES key */
+ if (kvm_has_pckmo_ecc(vcpu->kvm))
+ vcpu->arch.sie_block->ecd |= ECD_ECC;
+ }
+
if (vcpu->kvm->arch.crypto.dea_kw)
vcpu->arch.sie_block->ecb3 |= ECB3_DEA;
}
@@ -3065,6 +3169,17 @@ static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start,
}
}
+bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
+{
+ /* do not poll with more than halt_poll_max_steal percent of steal time */
+ if (S390_lowcore.avg_steal_timer * 100 / (TICK_USEC << 12) >=
+ halt_poll_max_steal) {
+ vcpu->stat.halt_no_poll_steal++;
+ return true;
+ }
+ return false;
+}
+
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
/* kvm common code refers to this, but never calls it */
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index d62fa148558b..076090f9e666 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -288,7 +288,9 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
unsigned long *b1, *b2;
u8 ecb3_flags;
+ u32 ecd_flags;
int apie_h;
+ int apie_s;
int key_msk = test_kvm_facility(vcpu->kvm, 76);
int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
@@ -297,7 +299,8 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
scb_s->crycbd = 0;
apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
- if (!apie_h && (!key_msk || fmt_o == CRYCB_FORMAT0))
+ apie_s = apie_h & scb_o->eca;
+ if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
return 0;
if (!crycb_addr)
@@ -308,7 +311,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
((crycb_addr + 128) & PAGE_MASK))
return set_validity_icpt(scb_s, 0x003CU);
- if (apie_h && (scb_o->eca & ECA_APIE)) {
+ if (apie_s) {
ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
vcpu->kvm->arch.crypto.crycb,
fmt_o, fmt_h);
@@ -320,7 +323,8 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
/* we may only allow it if enabled for guest 2 */
ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
(ECB3_AES | ECB3_DEA);
- if (!ecb3_flags)
+ ecd_flags = scb_o->ecd & vcpu->arch.sie_block->ecd & ECD_ECC;
+ if (!ecb3_flags && !ecd_flags)
goto end;
/* copy only the wrapping keys */
@@ -329,6 +333,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
return set_validity_icpt(scb_s, 0x0035U);
scb_s->ecb3 |= ecb3_flags;
+ scb_s->ecd |= ecd_flags;
/* xor both blocks in one run */
b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
@@ -339,7 +344,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
end:
switch (ret) {
case -EINVAL:
- return set_validity_icpt(scb_s, 0x0020U);
+ return set_validity_icpt(scb_s, 0x0022U);
case -EFAULT:
return set_validity_icpt(scb_s, 0x0035U);
case -EACCES:
diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c
index fd788e0f2e5b..cead9e0dcffb 100644
--- a/arch/s390/tools/gen_facilities.c
+++ b/arch/s390/tools/gen_facilities.c
@@ -93,6 +93,9 @@ static struct facility_def facility_defs[] = {
131, /* enhanced-SOP 2 and side-effect */
139, /* multiple epoch facility */
146, /* msa extension 8 */
+ 150, /* enhanced sort */
+ 151, /* deflate conversion */
+ 155, /* msa extension 9 */
-1 /* END */
}
},
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 640a03642766..43f87ad83ff4 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1307,6 +1307,16 @@ static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
}
#endif /* CONFIG_HAVE_KVM_INVALID_WAKEUPS */
+#ifdef CONFIG_HAVE_KVM_NO_POLL
+/* Callback that tells if we must not poll */
+bool kvm_arch_no_poll(struct kvm_vcpu *vcpu);
+#else
+static inline bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
+{
+ return false;
+}
+#endif /* CONFIG_HAVE_KVM_NO_POLL */
+
#ifdef CONFIG_HAVE_KVM_VCPU_ASYNC_IOCTL
long kvm_arch_vcpu_async_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg);
diff --git a/tools/arch/s390/include/uapi/asm/kvm.h b/tools/arch/s390/include/uapi/asm/kvm.h
index 16511d97e8dc..09652eabe769 100644
--- a/tools/arch/s390/include/uapi/asm/kvm.h
+++ b/tools/arch/s390/include/uapi/asm/kvm.h
@@ -152,7 +152,8 @@ struct kvm_s390_vm_cpu_subfunc {
__u8 pcc[16]; /* with MSA4 */
__u8 ppno[16]; /* with MSA5 */
__u8 kma[16]; /* with MSA8 */
- __u8 reserved[1808];
+ __u8 kdsa[16]; /* with MSA9 */
+ __u8 reserved[1792];
};
/* kvm attributes for crypto */
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index ea434ddc8499..aad9284c043a 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -57,3 +57,6 @@ config HAVE_KVM_VCPU_ASYNC_IOCTL
config HAVE_KVM_VCPU_RUN_PID_CHANGE
bool
+
+config HAVE_KVM_NO_POLL
+ bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 684b67252cd5..71ac0de892dc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2253,7 +2253,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
u64 block_ns;
start = cur = ktime_get();
- if (vcpu->halt_poll_ns) {
+ if (vcpu->halt_poll_ns && !kvm_arch_no_poll(vcpu)) {
ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
++vcpu->stat.halt_attempted_poll;