From 344c6c804703841d2bff4d68d7390ba726053874 Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Thu, 22 Aug 2019 22:30:20 +0800 Subject: KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH Hyper-V direct tlb flush function should be enabled for guest that only uses Hyper-V hypercall. User space hypervisor(e.g, Qemu) can disable KVM identification in CPUID and just exposes Hyper-V identification to make sure the precondition. Add new KVM capability KVM_CAP_ HYPERV_DIRECT_TLBFLUSH for user space to enable Hyper-V direct tlb function and this function is default to be disabled in KVM. Signed-off-by: Tianyu Lan Signed-off-by: Paolo Bonzini --- include/uapi/linux/kvm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 233efbb1c81c..c73aead0c0a8 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -999,6 +999,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_PTRAUTH_GENERIC 172 #define KVM_CAP_PMU_EVENT_FILTER 173 #define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174 +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 175 #ifdef KVM_CAP_IRQ_ROUTING -- cgit v1.2.3-70-g09d2 From e1572f1d08be57a5412a464cff0712a23cd0b73e Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 16 Sep 2019 18:22:56 +0200 Subject: cpu/SMT: create and export cpu_smt_possible() KVM needs to know if SMT is theoretically possible, this means it is supported and not forcefully disabled ('nosmt=force'). Create and export cpu_smt_possible() answering this question. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini --- include/linux/cpu.h | 2 ++ kernel/cpu.c | 11 +++++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 88dc0c653925..d0633ebdaa9c 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -201,12 +201,14 @@ enum cpuhp_smt_control { extern enum cpuhp_smt_control cpu_smt_control; extern void cpu_smt_disable(bool force); extern void cpu_smt_check_topology(void); +extern bool cpu_smt_possible(void); extern int cpuhp_smt_enable(void); extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval); #else # define cpu_smt_control (CPU_SMT_NOT_IMPLEMENTED) static inline void cpu_smt_disable(bool force) { } static inline void cpu_smt_check_topology(void) { } +static inline bool cpu_smt_possible(void) { return false; } static inline int cpuhp_smt_enable(void) { return 0; } static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; } #endif diff --git a/kernel/cpu.c b/kernel/cpu.c index e1967e9eddc2..fc28e17940e0 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -392,8 +392,7 @@ enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; void __init cpu_smt_disable(bool force) { - if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || - cpu_smt_control == CPU_SMT_NOT_SUPPORTED) + if (!cpu_smt_possible()) return; if (force) { @@ -438,6 +437,14 @@ static inline bool cpu_smt_allowed(unsigned int cpu) */ return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); } + +/* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ +bool cpu_smt_possible(void) +{ + return cpu_smt_control != CPU_SMT_FORCE_DISABLED && + cpu_smt_control != CPU_SMT_NOT_SUPPORTED; +} +EXPORT_SYMBOL_GPL(cpu_smt_possible); #else static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } #endif -- cgit v1.2.3-70-g09d2