diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index da87bb8670bb..9c74a732b08d 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2091,20 +2091,16 @@ 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.preemption_timer_deadline = + vmcs12->vmx_preemption_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; + } + return vmx->nested.preemption_timer_deadline - l1_scaled_tsc; } static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu, diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h index 3f3f780c8c65..43e24903812c 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 222e50104296..f159718f90c0 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 29200b606bcc..b4ff112e5c7e 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -46,6 +46,7 @@ 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 e244c6ecfc1d..919e161dd289 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 7428513a4c68..7cb19eca6c72 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 3d27069b9ed9..ccff3e6e2704 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 000000000000..cc72b6188ca7 --- /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 +#include +#include +#include +#include + +#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)) { + 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); +}