diff options
author | Wanpeng Li <wanpengli@tencent.com> | 2018-03-12 04:53:02 -0700 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-03-16 22:03:51 +0100 |
commit | 4d5422cea3b61f158d58924cbb43feada456ba5c (patch) | |
tree | 0657ac655c54892dd6498d8e20b89380255d592a /arch/x86/kvm | |
parent | 4956aa3b8b59e336b77f1df0ac7ce1a94c0265f2 (diff) |
KVM: X86: Provide a capability to disable MWAIT intercepts
Allowing a guest to execute MWAIT without interception enables a guest
to put a (physical) CPU into a power saving state, where it takes
longer to return from than what may be desired by the host.
Don't give a guest that power over a host by default. (Especially,
since nothing prevents a guest from using MWAIT even when it is not
advertised via CPUID.)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r-- | arch/x86/kvm/svm.c | 2 | ||||
-rw-r--r-- | arch/x86/kvm/vmx.c | 9 | ||||
-rw-r--r-- | arch/x86/kvm/x86.c | 24 | ||||
-rw-r--r-- | arch/x86/kvm/x86.h | 10 |
4 files changed, 31 insertions, 14 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index fa1c4977e1c2..f6578cee6bb6 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1398,7 +1398,7 @@ static void init_vmcb(struct vcpu_svm *svm) set_intercept(svm, INTERCEPT_XSETBV); set_intercept(svm, INTERCEPT_RSM); - if (!kvm_mwait_in_guest()) { + if (!kvm_mwait_in_guest(svm->vcpu.kvm)) { set_intercept(svm, INTERCEPT_MONITOR); set_intercept(svm, INTERCEPT_MWAIT); } diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index b4d8da6c62c8..7cef183993ba 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3746,13 +3746,11 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) CPU_BASED_UNCOND_IO_EXITING | CPU_BASED_MOV_DR_EXITING | CPU_BASED_USE_TSC_OFFSETING | + CPU_BASED_MWAIT_EXITING | + CPU_BASED_MONITOR_EXITING | CPU_BASED_INVLPG_EXITING | CPU_BASED_RDPMC_EXITING; - if (!kvm_mwait_in_guest()) - min |= CPU_BASED_MWAIT_EXITING | - CPU_BASED_MONITOR_EXITING; - opt = CPU_BASED_TPR_SHADOW | CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_ACTIVATE_SECONDARY_CONTROLS; @@ -5544,6 +5542,9 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx) exec_control |= CPU_BASED_CR3_STORE_EXITING | CPU_BASED_CR3_LOAD_EXITING | CPU_BASED_INVLPG_EXITING; + if (kvm_mwait_in_guest(vmx->vcpu.kvm)) + exec_control &= ~(CPU_BASED_MWAIT_EXITING | + CPU_BASED_MONITOR_EXITING); return exec_control; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9e1496cb2345..db95d4d6f57b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2813,9 +2813,15 @@ out: return r; } +static inline bool kvm_can_mwait_in_guest(void) +{ + return boot_cpu_has(X86_FEATURE_MWAIT) && + !boot_cpu_has_bug(X86_BUG_MONITOR); +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { - int r; + int r = 0; switch (ext) { case KVM_CAP_IRQCHIP: @@ -2871,8 +2877,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ADJUST_CLOCK: r = KVM_CLOCK_TSC_STABLE; break; - case KVM_CAP_X86_GUEST_MWAIT: - r = kvm_mwait_in_guest(); + case KVM_CAP_X86_DISABLE_EXITS: + if(kvm_can_mwait_in_guest()) + r |= KVM_X86_DISABLE_EXITS_MWAIT; break; case KVM_CAP_X86_SMM: /* SMBASE is usually relocated above 1M on modern chipsets, @@ -2913,7 +2920,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_X2APIC_API_VALID_FLAGS; break; default: - r = 0; break; } return r; @@ -4218,6 +4224,16 @@ split_irqchip_unlock: r = 0; break; + case KVM_CAP_X86_DISABLE_EXITS: + r = -EINVAL; + if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS) + break; + + if ((cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) && + kvm_can_mwait_in_guest()) + kvm->arch.mwait_in_guest = true; + r = 0; + break; default: r = -EINVAL; break; diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 18e2e0a91edc..026b239bf058 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -2,8 +2,6 @@ #ifndef ARCH_X86_KVM_X86_H #define ARCH_X86_KVM_X86_H -#include <asm/processor.h> -#include <asm/mwait.h> #include <linux/kvm_host.h> #include <asm/pvclock.h> #include "kvm_cache_regs.h" @@ -266,10 +264,12 @@ static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec) __rem; \ }) -static inline bool kvm_mwait_in_guest(void) +#define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) +#define KVM_X86_DISABLE_VALID_EXITS (KVM_X86_DISABLE_EXITS_MWAIT) + +static inline bool kvm_mwait_in_guest(struct kvm *kvm) { - return boot_cpu_has(X86_FEATURE_MWAIT) && - !boot_cpu_has_bug(X86_BUG_MONITOR); + return kvm->arch.mwait_in_guest; } #endif |