* [PATCH 1/2 v4] KVM: nVMX: Fix VMX preemption timer migration
2020-05-22 4:36 [PATCH 0/2 v4] Fix VMX preemption timer migration Makarand Sonare
@ 2020-05-22 4:36 ` Makarand Sonare
2020-05-22 7:19 ` Paolo Bonzini
2020-05-22 4:36 ` [PATCH 2/2 v4] KVM: selftests: VMX preemption timer migration test Makarand Sonare
1 sibling, 1 reply; 4+ messages in thread
From: Makarand Sonare @ 2020-05-22 4:36 UTC (permalink / raw)
To: kvm, pshier, jmattson; +Cc: Makarand Sonare
From: Peter Shier <pshier@google.com>
Add new field to hold preemption timer expiration deadline
appended to struct kvm_vmx_nested_state_hdr. This is to prevent
the first VM-Enter after migration from incorrectly restarting the timer
with the full timer value instead of partially decayed timer value.
KVM_SET_NESTED_STATE restarts timer using migrated state regardless
of whether L1 sets VM_EXIT_SAVE_VMX_PREEMPTION_TIMER.
Fixes: cf8b84f48a593 ("kvm: nVMX: Prepare for checkpointing L2 state")
Signed-off-by: Peter Shier <pshier@google.com>
Signed-off-by: Makarand Sonare <makarandsonare@google.com>
---
Documentation/virt/kvm/api.rst | 5 +++
arch/x86/include/uapi/asm/kvm.h | 4 +++
arch/x86/kvm/vmx/nested.c | 58 ++++++++++++++++++++++++++++-----
arch/x86/kvm/vmx/vmx.h | 2 ++
arch/x86/kvm/x86.c | 1 +
include/uapi/linux/kvm.h | 1 +
6 files changed, 62 insertions(+), 9 deletions(-)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index d871dacb984e9..a5ebe88cb7348 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -4326,6 +4326,9 @@ Errors:
#define KVM_STATE_NESTED_RUN_PENDING 0x00000002
#define KVM_STATE_NESTED_EVMCS 0x00000004
+ /* Available with KVM_CAP_NESTED_STATE_PREEMPTION_TIMER */
+ #define KVM_STATE_NESTED_PREEMPTION_TIMER 0x00000010
+
#define KVM_STATE_NESTED_FORMAT_VMX 0
#define KVM_STATE_NESTED_FORMAT_SVM 1
@@ -4335,8 +4338,10 @@ Errors:
#define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002
struct kvm_vmx_nested_state_hdr {
+ __u32 flags;
__u64 vmxon_pa;
__u64 vmcs12_pa;
+ __u64 preemption_timer_deadline;
struct {
__u16 flags;
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 3f3f780c8c650..ae7ccb5e8747d 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -391,6 +391,8 @@ struct kvm_sync_regs {
#define KVM_STATE_NESTED_RUN_PENDING 0x00000002
#define KVM_STATE_NESTED_EVMCS 0x00000004
#define KVM_STATE_NESTED_MTF_PENDING 0x00000008
+/* Available with KVM_CAP_NESTED_STATE_PREEMPTION_TIMER */
+#define KVM_STATE_NESTED_PREEMPTION_TIMER 0x00000010
#define KVM_STATE_NESTED_SMM_GUEST_MODE 0x00000001
#define KVM_STATE_NESTED_SMM_VMXON 0x00000002
@@ -403,8 +405,10 @@ struct kvm_vmx_nested_state_data {
};
struct kvm_vmx_nested_state_hdr {
+ __u32 flags;
__u64 vmxon_pa;
__u64 vmcs12_pa;
+ __u64 preemption_timer_deadline;
struct {
__u16 flags;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 51ebb60e1533a..a50cb99c4ed01 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2092,9 +2092,29 @@ static enum hrtimer_restart vmx_preemption_timer_fn(struct hrtimer *timer)
return HRTIMER_NORESTART;
}
-static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
+static u64 vmx_calc_preemption_timer_value(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+ u64 timer_value = 0;
+
+ u64 l1_scaled_tsc = kvm_read_l1_tsc(vcpu, rdtsc()) >>
+ VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE;
+
+ if (!vmx->nested.has_preemption_timer_deadline) {
+ timer_value = vmcs12->vmx_preemption_timer_value;
+ vmx->nested.preemption_timer_deadline = timer_value +
+ l1_scaled_tsc;
+ vmx->nested.has_preemption_timer_deadline = true;
+ } else if (l1_scaled_tsc < vmx->nested.preemption_timer_deadline)
+ timer_value = vmx->nested.preemption_timer_deadline -
+ l1_scaled_tsc;
+ return timer_value;
+}
+
+static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu,
+ u64 preemption_timeout)
{
- u64 preemption_timeout = get_vmcs12(vcpu)->vmx_preemption_timer_value;
struct vcpu_vmx *vmx = to_vmx(vcpu);
/*
@@ -3353,8 +3373,10 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
* the timer.
*/
vmx->nested.preemption_timer_expired = false;
- if (nested_cpu_has_preemption_timer(vmcs12))
- vmx_start_preemption_timer(vcpu);
+ if (nested_cpu_has_preemption_timer(vmcs12)) {
+ u64 timer_value = vmx_calc_preemption_timer_value(vcpu);
+ vmx_start_preemption_timer(vcpu, timer_value);
+ }
/*
* Note no nested_vmx_succeed or nested_vmx_fail here. At this point
@@ -3462,6 +3484,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
* the nested entry.
*/
vmx->nested.nested_run_pending = 1;
+ vmx->nested.has_preemption_timer_deadline = false;
status = nested_vmx_enter_non_root_mode(vcpu, true);
if (unlikely(status != NVMX_VMENTRY_SUCCESS))
goto vmentry_failed;
@@ -3962,9 +3985,10 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
vmcs12->guest_activity_state = GUEST_ACTIVITY_ACTIVE;
if (nested_cpu_has_preemption_timer(vmcs12) &&
- vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER)
- vmcs12->vmx_preemption_timer_value =
- vmx_get_preemption_timer_value(vcpu);
+ vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER &&
+ !vmx->nested.nested_run_pending)
+ vmcs12->vmx_preemption_timer_value =
+ vmx_get_preemption_timer_value(vcpu);
/*
* In some cases (usually, nested EPT), L2 is allowed to change its
@@ -5896,8 +5920,10 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
.flags = 0,
.format = KVM_STATE_NESTED_FORMAT_VMX,
.size = sizeof(kvm_state),
+ .hdr.vmx.flags = 0,
.hdr.vmx.vmxon_pa = -1ull,
.hdr.vmx.vmcs12_pa = -1ull,
+ .hdr.vmx.preemption_timer_deadline = 0,
};
struct kvm_vmx_nested_state_data __user *user_vmx_nested_state =
&user_kvm_nested_state->data.vmx[0];
@@ -5939,6 +5965,14 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
if (vmx->nested.mtf_pending)
kvm_state.flags |= KVM_STATE_NESTED_MTF_PENDING;
+
+ if (nested_cpu_has_preemption_timer(vmcs12) &&
+ vmx->nested.has_preemption_timer_deadline) {
+ kvm_state.hdr.vmx.flags |=
+ KVM_STATE_NESTED_PREEMPTION_TIMER;
+ kvm_state.hdr.vmx.preemption_timer_deadline =
+ vmx->nested.preemption_timer_deadline;
+ }
}
}
@@ -5984,7 +6018,6 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu,
get_shadow_vmcs12(vcpu), VMCS12_SIZE))
return -EFAULT;
}
-
out:
return kvm_state.size;
}
@@ -6056,7 +6089,8 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
*/
if (is_smm(vcpu) ?
(kvm_state->flags &
- (KVM_STATE_NESTED_GUEST_MODE | KVM_STATE_NESTED_RUN_PENDING))
+ (KVM_STATE_NESTED_GUEST_MODE | KVM_STATE_NESTED_RUN_PENDING |
+ KVM_STATE_NESTED_PREEMPTION_TIMER))
: kvm_state->hdr.vmx.smm.flags)
return -EINVAL;
@@ -6146,6 +6180,12 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
goto error_guest_mode;
}
+ if (kvm_state->hdr.vmx.flags & KVM_STATE_NESTED_PREEMPTION_TIMER) {
+ vmx->nested.has_preemption_timer_deadline = true;
+ vmx->nested.preemption_timer_deadline =
+ kvm_state->hdr.vmx.preemption_timer_deadline;
+ }
+
if (nested_vmx_check_controls(vcpu, vmcs12) ||
nested_vmx_check_host_state(vcpu, vmcs12) ||
nested_vmx_check_guest_state(vcpu, vmcs12, &ignored))
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 298ddef79d009..672c28f17e497 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -169,6 +169,8 @@ struct nested_vmx {
u16 posted_intr_nv;
struct hrtimer preemption_timer;
+ u64 preemption_timer_deadline;
+ bool has_preemption_timer_deadline;
bool preemption_timer_expired;
/* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 471fccf7f8501..e73309879255c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3418,6 +3418,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_MSR_PLATFORM_INFO:
case KVM_CAP_EXCEPTION_PAYLOAD:
case KVM_CAP_SET_GUEST_DEBUG:
+ case KVM_CAP_NESTED_STATE_PREEMPTION_TIMER:
r = 1;
break;
case KVM_CAP_SYNC_REGS:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ac9eba0289d1b..0868dce12a715 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1018,6 +1018,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_S390_PROTECTED 180
#define KVM_CAP_PPC_SECURE_GUEST 181
#define KVM_CAP_HALT_POLL 182
+#define KVM_CAP_NESTED_STATE_PREEMPTION_TIMER 183
#ifdef KVM_CAP_IRQ_ROUTING
--
2.27.0.rc0.183.gde8f92d652-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/2 v4] KVM: selftests: VMX preemption timer migration test
2020-05-22 4:36 [PATCH 0/2 v4] Fix VMX preemption timer migration Makarand Sonare
2020-05-22 4:36 ` [PATCH 1/2 v4] KVM: nVMX: " Makarand Sonare
@ 2020-05-22 4:36 ` Makarand Sonare
1 sibling, 0 replies; 4+ messages in thread
From: Makarand Sonare @ 2020-05-22 4:36 UTC (permalink / raw)
To: kvm, pshier, jmattson; +Cc: Makarand Sonare
When a nested VM with a VMX-preemption timer is migrated, verify that the
nested VM and its parent VM observe the VMX-preemption timer exit close to
the original expiration deadline.
Signed-off-by: Makarand Sonare <makarandsonare@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
---
tools/arch/x86/include/uapi/asm/kvm.h | 1 +
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../testing/selftests/kvm/include/kvm_util.h | 2 +
.../selftests/kvm/include/x86_64/processor.h | 11 +-
.../selftests/kvm/include/x86_64/vmx.h | 27 ++
.../kvm/x86_64/vmx_preemption_timer_test.c | 255 ++++++++++++++++++
7 files changed, 294 insertions(+), 4 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index 3f3f780c8c650..43e24903812c4 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -400,6 +400,7 @@ struct kvm_sync_regs {
struct kvm_vmx_nested_state_data {
__u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
__u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE];
+ __u64 preemption_timer_deadline;
};
struct kvm_vmx_nested_state_hdr {
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 222e50104296a..f159718f90c0a 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -10,6 +10,7 @@
/x86_64/set_sregs_test
/x86_64/smm_test
/x86_64/state_test
+/x86_64/vmx_preemption_timer_test
/x86_64/svm_vmcall_test
/x86_64/sync_regs_test
/x86_64/vmx_close_while_nested_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c66f4eec34111..780f0c189a7bc 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -20,6 +20,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
TEST_GEN_PROGS_x86_64 += x86_64/smm_test
TEST_GEN_PROGS_x86_64 += x86_64/state_test
+TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index e244c6ecfc1d5..919e161dd2893 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -314,6 +314,8 @@ void ucall_uninit(struct kvm_vm *vm);
void ucall(uint64_t cmd, int nargs, ...);
uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
+#define GUEST_SYNC_ARGS(stage, arg1, arg2, arg3, arg4) \
+ ucall(UCALL_SYNC, 6, "hello", stage, arg1, arg2, arg3, arg4)
#define GUEST_SYNC(stage) ucall(UCALL_SYNC, 2, "hello", stage)
#define GUEST_DONE() ucall(UCALL_DONE, 0)
#define __GUEST_ASSERT(_condition, _nargs, _args...) do { \
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 7428513a4c687..7cb19eca6c72d 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -79,13 +79,16 @@ static inline uint64_t get_desc64_base(const struct desc64 *desc)
static inline uint64_t rdtsc(void)
{
uint32_t eax, edx;
-
+ uint32_t tsc_val;
/*
* The lfence is to wait (on Intel CPUs) until all previous
- * instructions have been executed.
+ * instructions have been executed. If software requires RDTSC to be
+ * executed prior to execution of any subsequent instruction, it can
+ * execute LFENCE immediately after RDTSC
*/
- __asm__ __volatile__("lfence; rdtsc" : "=a"(eax), "=d"(edx));
- return ((uint64_t)edx) << 32 | eax;
+ __asm__ __volatile__("lfence; rdtsc; lfence" : "=a"(eax), "=d"(edx));
+ tsc_val = ((uint64_t)edx) << 32 | eax;
+ return tsc_val;
}
static inline uint64_t rdtscp(uint32_t *aux)
diff --git a/tools/testing/selftests/kvm/include/x86_64/vmx.h b/tools/testing/selftests/kvm/include/x86_64/vmx.h
index 3d27069b9ed9c..ccff3e6e27048 100644
--- a/tools/testing/selftests/kvm/include/x86_64/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/vmx.h
@@ -575,6 +575,33 @@ struct vmx_pages {
void *eptp;
};
+union vmx_basic {
+ u64 val;
+ struct {
+ u32 revision;
+ u32 size:13,
+ reserved1:3,
+ width:1,
+ dual:1,
+ type:4,
+ insouts:1,
+ ctrl:1,
+ vm_entry_exception_ctrl:1,
+ reserved2:7;
+ };
+};
+
+union vmx_ctrl_msr {
+ u64 val;
+ struct {
+ u32 set, clr;
+ };
+};
+
+union vmx_basic basic;
+union vmx_ctrl_msr ctrl_pin_rev;
+union vmx_ctrl_msr ctrl_exit_rev;
+
struct vmx_pages *vcpu_alloc_vmx(struct kvm_vm *vm, vm_vaddr_t *p_vmx_gva);
bool prepare_for_vmx_operation(struct vmx_pages *vmx);
void prepare_vmcs(struct vmx_pages *vmx, void *guest_rip, void *guest_rsp);
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c b/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
new file mode 100644
index 0000000000000..e2f5dccb4d5ba
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_preemption_timer_test.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VMX-preemption timer test
+ *
+ * Copyright (C) 2020, Google, LLC.
+ *
+ * Test to ensure the VM-Enter after migration doesn't
+ * incorrectly restarts the timer with the full timer
+ * value instead of partially decayed timer value
+ *
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+
+#define VCPU_ID 5
+#define PREEMPTION_TIMER_VALUE 100000000ull
+#define PREEMPTION_TIMER_VALUE_THRESHOLD1 80000000ull
+
+u32 vmx_pt_rate;
+bool l2_save_restore_done;
+static u64 l2_vmx_pt_start;
+volatile u64 l2_vmx_pt_finish;
+
+void l2_guest_code(void)
+{
+ u64 vmx_pt_delta;
+
+ vmcall();
+ l2_vmx_pt_start = (rdtsc() >> vmx_pt_rate) << vmx_pt_rate;
+
+ /*
+ * Wait until the 1st threshold has passed
+ */
+ do {
+ l2_vmx_pt_finish = rdtsc();
+ vmx_pt_delta = (l2_vmx_pt_finish - l2_vmx_pt_start) >>
+ vmx_pt_rate;
+ } while (vmx_pt_delta < PREEMPTION_TIMER_VALUE_THRESHOLD1);
+
+ /*
+ * Force L2 through Save and Restore cycle
+ */
+ GUEST_SYNC(1);
+
+ l2_save_restore_done = 1;
+
+ /*
+ * Now wait for the preemption timer to fire and
+ * exit to L1
+ */
+ while ((l2_vmx_pt_finish = rdtsc()))
+ ;
+}
+
+void l1_guest_code(struct vmx_pages *vmx_pages)
+{
+#define L2_GUEST_STACK_SIZE 64
+ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+ u64 l1_vmx_pt_start;
+ u64 l1_vmx_pt_finish;
+ u64 l1_tsc_deadline, l2_tsc_deadline;
+
+ GUEST_ASSERT(vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+ GUEST_ASSERT(load_vmcs(vmx_pages));
+ GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+
+ prepare_vmcs(vmx_pages, l2_guest_code,
+ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+ /*
+ * Check for Preemption timer support
+ */
+ basic.val = rdmsr(MSR_IA32_VMX_BASIC);
+ ctrl_pin_rev.val = rdmsr(basic.ctrl ? MSR_IA32_VMX_TRUE_PINBASED_CTLS
+ : MSR_IA32_VMX_PINBASED_CTLS);
+ ctrl_exit_rev.val = rdmsr(basic.ctrl ? MSR_IA32_VMX_TRUE_EXIT_CTLS
+ : MSR_IA32_VMX_EXIT_CTLS);
+
+ if (!(ctrl_pin_rev.clr & PIN_BASED_VMX_PREEMPTION_TIMER) ||
+ !(ctrl_exit_rev.clr & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER))
+ return;
+
+ GUEST_ASSERT(!vmlaunch());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+ vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + vmreadz(VM_EXIT_INSTRUCTION_LEN));
+
+ /*
+ * Turn on PIN control and resume the guest
+ */
+ GUEST_ASSERT(!vmwrite(PIN_BASED_VM_EXEC_CONTROL,
+ vmreadz(PIN_BASED_VM_EXEC_CONTROL) |
+ PIN_BASED_VMX_PREEMPTION_TIMER));
+
+ GUEST_ASSERT(!vmwrite(VMX_PREEMPTION_TIMER_VALUE,
+ PREEMPTION_TIMER_VALUE));
+
+ vmx_pt_rate = rdmsr(MSR_IA32_VMX_MISC) & 0x1F;
+
+ l2_save_restore_done = 0;
+
+ l1_vmx_pt_start = (rdtsc() >> vmx_pt_rate) << vmx_pt_rate;
+
+ GUEST_ASSERT(!vmresume());
+
+ l1_vmx_pt_finish = rdtsc();
+
+ /*
+ * Ensure exit from L2 happens after L2 goes through
+ * save and restore
+ */
+ GUEST_ASSERT(l2_save_restore_done);
+
+ /*
+ * Ensure the exit from L2 is due to preemption timer expiry
+ */
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_PREEMPTION_TIMER);
+
+ l1_tsc_deadline = l1_vmx_pt_start +
+ (PREEMPTION_TIMER_VALUE << vmx_pt_rate);
+
+ l2_tsc_deadline = l2_vmx_pt_start +
+ (PREEMPTION_TIMER_VALUE << vmx_pt_rate);
+
+ /*
+ * Sync with the host and pass the l1|l2 pt_expiry_finish times and
+ * tsc deadlines so that host can verify they are as expected
+ */
+ GUEST_SYNC_ARGS(2, l1_vmx_pt_finish, l1_tsc_deadline,
+ l2_vmx_pt_finish, l2_tsc_deadline);
+}
+
+void guest_code(struct vmx_pages *vmx_pages)
+{
+ if (vmx_pages)
+ l1_guest_code(vmx_pages);
+
+ GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+ vm_vaddr_t vmx_pages_gva = 0;
+
+ struct kvm_regs regs1, regs2;
+ struct kvm_vm *vm;
+ struct kvm_run *run;
+ struct kvm_x86_state *state;
+ struct ucall uc;
+ int stage;
+
+ /*
+ * AMD currently does not implement any VMX features, so for now we
+ * just early out.
+ */
+ nested_vmx_check_supported();
+
+ /* Create VM */
+ vm = vm_create_default(VCPU_ID, 0, guest_code);
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+ run = vcpu_state(vm, VCPU_ID);
+
+ vcpu_regs_get(vm, VCPU_ID, ®s1);
+
+ if (kvm_check_cap(KVM_CAP_NESTED_STATE_PREEMPTION_TIMER)) {
+ vcpu_alloc_vmx(vm, &vmx_pages_gva);
+ vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+ } else {
+ pr_info("will skip vmx preemption timer checks\n");
+ goto done;
+ }
+
+ for (stage = 1;; stage++) {
+ _vcpu_run(vm, VCPU_ID);
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Stage %d: unexpected exit reason: %u (%s),\n",
+ stage, run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vm, VCPU_ID, &uc)) {
+ case UCALL_ABORT:
+ TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
+ __FILE__, uc.args[1]);
+ /* NOT REACHED */
+ case UCALL_SYNC:
+ break;
+ case UCALL_DONE:
+ goto done;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+
+ /* UCALL_SYNC is handled here. */
+ TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
+ uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
+ stage, (ulong)uc.args[1]);
+ /*
+ * If this stage 2 then we should verify the vmx pt expiry
+ * is as expected.
+ * From L1's perspective verify Preemption timer hasn't
+ * expired too early.
+ * From L2's perspective verify Preemption timer hasn't
+ * expired too late.
+ */
+ if (stage == 2) {
+
+ pr_info("Stage %d: L1 PT expiry TSC (%lu) , L1 TSC deadline (%lu)\n",
+ stage, uc.args[2], uc.args[3]);
+
+ pr_info("Stage %d: L2 PT expiry TSC (%lu) , L2 TSC deadline (%lu)\n",
+ stage, uc.args[4], uc.args[5]);
+
+ TEST_ASSERT(uc.args[2] >= uc.args[3],
+ "Stage %d: L1 PT expiry TSC (%lu) < L1 TSC deadline (%lu)",
+ stage, uc.args[2], uc.args[3]);
+
+ TEST_ASSERT(uc.args[4] < uc.args[5],
+ "Stage %d: L2 PT expiry TSC (%lu) > L2 TSC deadline (%lu)",
+ stage, uc.args[4], uc.args[5]);
+ }
+
+ state = vcpu_save_state(vm, VCPU_ID);
+ memset(®s1, 0, sizeof(regs1));
+ vcpu_regs_get(vm, VCPU_ID, ®s1);
+
+ kvm_vm_release(vm);
+
+ /* Restore state in a new VM. */
+ kvm_vm_restart(vm, O_RDWR);
+ vm_vcpu_add(vm, VCPU_ID);
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+ vcpu_load_state(vm, VCPU_ID, state);
+ run = vcpu_state(vm, VCPU_ID);
+ free(state);
+
+ memset(®s2, 0, sizeof(regs2));
+ vcpu_regs_get(vm, VCPU_ID, ®s2);
+ TEST_ASSERT(!memcmp(®s1, ®s2, sizeof(regs2)),
+ "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
+ (ulong) regs2.rdi, (ulong) regs2.rsi);
+ }
+
+done:
+ kvm_vm_free(vm);
+}
--
2.27.0.rc0.183.gde8f92d652-goog
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