diff options
| author | Wanpeng Li <wanpengli@tencent.com> | 2018-02-13 09:05:40 +0800 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2018-03-06 18:40:44 +0100 |
| commit | a4429e53c9b3082b05e51224c3d58dbdd39306c5 (patch) | |
| tree | d0fbeff12679477198902c365cb23ad6b645747c /arch/x86 | |
| parent | d4c67a7a54f12cb8d267284212f1072c95917e5a (diff) | |
KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED
This patch introduces kvm_para_has_hint() to query for hints about
the configuration of the guests. The first hint KVM_HINTS_DEDICATED,
is set if the guest has dedicated physical CPUs for each vCPU (i.e.
pinning and no over-commitment). This allows optimizing spinlocks
and tells the guest to avoid PV TLB flush.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/kvm_para.h | 6 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/kvm_para.h | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/kvm.c | 5 |
3 files changed, 17 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 7b407dda2bd7..3aea2658323a 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -88,6 +88,7 @@ static inline long kvm_hypercall4(unsigned int nr, unsigned long p1, #ifdef CONFIG_KVM_GUEST bool kvm_para_available(void); unsigned int kvm_arch_para_features(void); +unsigned int kvm_arch_para_hints(void); void kvm_async_pf_task_wait(u32 token, int interrupt_kernel); void kvm_async_pf_task_wake(u32 token); u32 kvm_read_and_reset_pf_reason(void); @@ -115,6 +116,11 @@ static inline unsigned int kvm_arch_para_features(void) return 0; } +static inline unsigned int kvm_arch_para_hints(void) +{ + return 0; +} + static inline u32 kvm_read_and_reset_pf_reason(void) { return 0; diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 6cfa9c8cb7d6..68a41b6ba3da 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -10,8 +10,10 @@ */ #define KVM_CPUID_SIGNATURE 0x40000000 -/* This CPUID returns a feature bitmap in eax. Before enabling a particular - * paravirtualization, the appropriate feature bit should be checked. +/* This CPUID returns two feature bitmaps in eax, edx. Before enabling + * a particular paravirtualization, the appropriate feature bit should + * be checked in eax. The performance hint feature bit should be checked + * in edx. */ #define KVM_CPUID_FEATURES 0x40000001 #define KVM_FEATURE_CLOCKSOURCE 0 @@ -28,6 +30,8 @@ #define KVM_FEATURE_PV_TLB_FLUSH 9 #define KVM_FEATURE_ASYNC_PF_VMEXIT 10 +#define KVM_HINTS_DEDICATED 0 + /* The last 8 bits are used to indicate how to interpret the flags field * in pvclock structure. If no bits are set, all flags are ignored. */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index bc1a27280c4b..8c9d98c46f84 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -605,6 +605,11 @@ unsigned int kvm_arch_para_features(void) return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES); } +unsigned int kvm_arch_para_hints(void) +{ + return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES); +} + static uint32_t __init kvm_detect(void) { return kvm_cpuid_base(); |