diff options
| -rw-r--r-- | arch/x86/include/asm/vmx.h | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx.c | 51 |
2 files changed, 54 insertions, 1 deletions
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h index 272514c2d45..2b4945419a8 100644 --- a/arch/x86/include/asm/vmx.h +++ b/arch/x86/include/asm/vmx.h @@ -56,6 +56,7 @@ #define SECONDARY_EXEC_ENABLE_VPID 0x00000020 #define SECONDARY_EXEC_WBINVD_EXITING 0x00000040 #define SECONDARY_EXEC_UNRESTRICTED_GUEST 0x00000080 +#define SECONDARY_EXEC_PAUSE_LOOP_EXITING 0x00000400 #define PIN_BASED_EXT_INTR_MASK 0x00000001 @@ -144,6 +145,8 @@ enum vmcs_field { VM_ENTRY_INSTRUCTION_LEN = 0x0000401a, TPR_THRESHOLD = 0x0000401c, SECONDARY_VM_EXEC_CONTROL = 0x0000401e, + PLE_GAP = 0x00004020, + PLE_WINDOW = 0x00004022, VM_INSTRUCTION_ERROR = 0x00004400, VM_EXIT_REASON = 0x00004402, VM_EXIT_INTR_INFO = 0x00004404, @@ -248,6 +251,7 @@ enum vmcs_field { #define EXIT_REASON_MSR_READ 31 #define EXIT_REASON_MSR_WRITE 32 #define EXIT_REASON_MWAIT_INSTRUCTION 36 +#define EXIT_REASON_PAUSE_INSTRUCTION 40 #define EXIT_REASON_MCE_DURING_VMENTRY 41 #define EXIT_REASON_TPR_BELOW_THRESHOLD 43 #define EXIT_REASON_APIC_ACCESS 44 diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 70020e505c2..a4580d65af5 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -61,6 +61,25 @@ module_param_named(unrestricted_guest, static int __read_mostly emulate_invalid_guest_state = 0; module_param(emulate_invalid_guest_state, bool, S_IRUGO); +/* + * These 2 parameters are used to config the controls for Pause-Loop Exiting: + * ple_gap: upper bound on the amount of time between two successive + * executions of PAUSE in a loop. Also indicate if ple enabled. + * According to test, this time is usually small than 41 cycles. + * ple_window: upper bound on the amount of time a guest is allowed to execute + * in a PAUSE loop. Tests indicate that most spinlocks are held for + * less than 2^12 cycles + * Time is measured based on a counter that runs at the same rate as the TSC, + * refer SDM volume 3b section 21.6.13 & 22.1.3. + */ +#define KVM_VMX_DEFAULT_PLE_GAP 41 +#define KVM_VMX_DEFAULT_PLE_WINDOW 4096 +static int ple_gap = KVM_VMX_DEFAULT_PLE_GAP; +module_param(ple_gap, int, S_IRUGO); + +static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW; +module_param(ple_window, int, S_IRUGO); + struct vmcs { u32 revision_id; u32 abort; @@ -319,6 +338,12 @@ static inline int cpu_has_vmx_unrestricted_guest(void) SECONDARY_EXEC_UNRESTRICTED_GUEST; } +static inline int cpu_has_vmx_ple(void) +{ + return vmcs_config.cpu_based_2nd_exec_ctrl & + SECONDARY_EXEC_PAUSE_LOOP_EXITING; +} + static inline int vm_need_virtualize_apic_accesses(struct kvm *kvm) { return flexpriority_enabled && @@ -1240,7 +1265,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) SECONDARY_EXEC_WBINVD_EXITING | SECONDARY_EXEC_ENABLE_VPID | SECONDARY_EXEC_ENABLE_EPT | - SECONDARY_EXEC_UNRESTRICTED_GUEST; + SECONDARY_EXEC_UNRESTRICTED_GUEST | + SECONDARY_EXEC_PAUSE_LOOP_EXITING; if (adjust_vmx_controls(min2, opt2, MSR_IA32_VMX_PROCBASED_CTLS2, &_cpu_based_2nd_exec_control) < 0) @@ -1386,6 +1412,9 @@ static __init int hardware_setup(void) if (enable_ept && !cpu_has_vmx_ept_2m_page()) kvm_disable_largepages(); + if (!cpu_has_vmx_ple()) + ple_gap = 0; + return alloc_kvm_area(); } @@ -2298,9 +2327,16 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) exec_control &= ~SECONDARY_EXEC_ENABLE_EPT; if (!enable_unrestricted_guest) exec_control &= ~SECONDARY_EXEC_UNRESTRICTED_GUEST; + if (!ple_gap) + exec_control &= ~SECONDARY_EXEC_PAUSE_LOOP_EXITING; vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control); } + if (ple_gap) { + vmcs_write32(PLE_GAP, ple_gap); + vmcs_write32(PLE_WINDOW, ple_window); + } + vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, !!bypass_guest_pf); vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, !!bypass_guest_pf); vmcs_write32(CR3_TARGET_COUNT, 0); /* 22.2.1 */ @@ -3348,6 +3384,18 @@ out: } /* + * Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE + * exiting, so only get here on cpu with PAUSE-Loop-Exiting. + */ +static int handle_pause(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) +{ + skip_emulated_instruction(vcpu); + kvm_vcpu_on_spin(vcpu); + + return 1; +} + +/* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs * to be done to userspace and return 0. @@ -3383,6 +3431,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { [EXIT_REASON_MCE_DURING_VMENTRY] = handle_machine_check, [EXIT_REASON_EPT_VIOLATION] = handle_ept_violation, [EXIT_REASON_EPT_MISCONFIG] = handle_ept_misconfig, + [EXIT_REASON_PAUSE_INSTRUCTION] = handle_pause, }; static const int kvm_vmx_max_exit_handlers = |