This patch implements two new vm-ioctls to get and set the virtual_tsc_khz if the machine supports tsc-scaling. Setting the tsc-frequency is only possible before userspace creates any vcpu.
Signed-off-by: Joerg Roedel <[email protected]> --- Documentation/kvm/api.txt | 22 +++++++++++++++ arch/x86/include/asm/kvm_host.h | 7 +++++ arch/x86/kvm/svm.c | 15 ++++++++++ arch/x86/kvm/x86.c | 56 +++++++++++++++++++++++++++++++++++++++ include/linux/kvm.h | 5 +++ 5 files changed, 105 insertions(+), 0 deletions(-) diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index ad85797..adc9c23 100644 --- a/Documentation/kvm/api.txt +++ b/Documentation/kvm/api.txt @@ -1263,6 +1263,28 @@ struct kvm_assigned_msix_entry { __u16 padding[3]; }; +4.54 KVM_SET_TSC_KHZ + +Capability: KVM_CAP_TSC_CONTROL +Architectures: x86 +Type: vm ioctl +Parameters: __u32 (in) +Returns: 0 on success, -1 on error + +Specifies the tsc frequency for the virtual machine. This IOCTL must be +used before any vcpu is created. The unit of the frequency is KHz. + +4.55 KVM_GET_TSC_KHZ + +Capability: KVM_CAP_GET_TSC_KHZ +Architectures: x86 +Type: vm ioctl +Parameters: __u32 (out) +Returns: 0 on success, -1 on error + +Returns the tsc frequency of the guest. The unit of the return value is +KHz. If the host has unstable tsc this ioctl return an error. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 16db838..2471fc9 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -630,6 +630,13 @@ u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn); extern bool tdp_enabled; +/* control of guest tsc rate supported? */ +extern bool kvm_has_tsc_control; +/* minimum supported tsc_khz for guests */ +extern u32 kvm_min_guest_tsc_khz; +/* maximum supported tsc_khz for guests */ +extern u32 kvm_max_guest_tsc_khz; + enum emulation_result { EMULATE_DONE, /* no further processing */ EMULATE_DO_MMIO, /* kvm_run filled with mmio request */ diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index b8c6d28..ed7d608 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -64,6 +64,8 @@ MODULE_LICENSE("GPL"); #define DEBUGCTL_RESERVED_BITS (~(0x3fULL)) #define TSC_RATIO_RSVD 0xffffff0000000000ULL +#define TSC_RATIO_MIN 0x0000000000000001ULL +#define TSC_RATIO_MAX 0x000000ffffffffffULL static bool erratum_383_found __read_mostly; @@ -198,6 +200,7 @@ static int nested_svm_intercept(struct vcpu_svm *svm); static int nested_svm_vmexit(struct vcpu_svm *svm); static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr, bool has_error_code, u32 error_code); +static u64 __scale_tsc(u64 ratio, u64 tsc); enum { VMCB_INTERCEPTS, /* Intercept vectors, TSC offset, @@ -799,6 +802,18 @@ static __init int svm_hardware_setup(void) if (boot_cpu_has(X86_FEATURE_FXSR_OPT)) kvm_enable_efer_bits(EFER_FFXSR); + if (boot_cpu_has(X86_FEATURE_TSCRATEMSR)) { + u64 min, max; + + kvm_has_tsc_control = true; + + min = max(1ULL, __scale_tsc(tsc_khz, TSC_RATIO_MIN)); + max = min(0xffffffffULL, __scale_tsc(tsc_khz, TSC_RATIO_MAX)); + + kvm_min_guest_tsc_khz = min; + kvm_max_guest_tsc_khz = max; + } + if (nested) { printk(KERN_INFO "kvm: Nested Virtualization enabled\n"); kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index aecd926..de313f1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -100,6 +100,13 @@ EXPORT_SYMBOL_GPL(kvm_x86_ops); int ignore_msrs = 0; module_param_named(ignore_msrs, ignore_msrs, bool, S_IRUGO | S_IWUSR); +bool kvm_has_tsc_control; +u32 kvm_min_guest_tsc_khz; +u32 kvm_max_guest_tsc_khz; +EXPORT_SYMBOL_GPL(kvm_has_tsc_control); +EXPORT_SYMBOL_GPL(kvm_min_guest_tsc_khz); +EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz); + #define KVM_NR_SHARED_MSRS 16 struct kvm_shared_msrs_global { @@ -2000,6 +2007,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_X86_ROBUST_SINGLESTEP: case KVM_CAP_XSAVE: case KVM_CAP_ASYNC_PF: + case KVM_CAP_GET_TSC_KHZ: r = 1; break; case KVM_CAP_COALESCED_MMIO: @@ -2026,6 +2034,9 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_XCRS: r = cpu_has_xsave; break; + case KVM_CAP_TSC_CONTROL: + r = kvm_has_tsc_control; + break; default: r = 0; break; @@ -3580,6 +3591,51 @@ long kvm_arch_vm_ioctl(struct file *filp, r = 0; break; } + case KVM_SET_TSC_KHZ: { + u32 user_tsc_khz; + + if (!kvm_has_tsc_control) + break; + + r = -EFAULT; + if (copy_from_user(&user_tsc_khz, argp, sizeof(__u32))) + goto out; + + r = -EINVAL; + if (user_tsc_khz < kvm_min_guest_tsc_khz || + user_tsc_khz > kvm_max_guest_tsc_khz) + goto out; + + mutex_lock(&kvm->lock); + /* + * We force the tsc frequency to be set before any + * vcpu is created + */ + if (atomic_read(&kvm->online_vcpus) > 0) { + mutex_unlock(&kvm->lock); + goto out; + } + + kvm_arch_set_tsc_khz(kvm, user_tsc_khz); + + mutex_unlock(&kvm->lock); + + r = 0; + goto out; + } + case KVM_GET_TSC_KHZ: { + + r = -EIO; + if (check_tsc_unstable()) + goto out; + + r = -EFAULT; + if (copy_to_user(argp, &kvm->arch.virtual_tsc_khz, sizeof(__u32))) + goto out; + + r = 0; + goto out; + } default: ; diff --git a/include/linux/kvm.h b/include/linux/kvm.h index ea2dc1a..ea16c57 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -541,6 +541,8 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_PPC_GET_PVINFO 57 #define KVM_CAP_PPC_IRQ_LEVEL 58 #define KVM_CAP_ASYNC_PF 59 +#define KVM_CAP_TSC_CONTROL 60 +#define KVM_CAP_GET_TSC_KHZ 61 #ifdef KVM_CAP_IRQ_ROUTING @@ -677,6 +679,9 @@ struct kvm_clock_data { #define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, struct kvm_pit_state2) /* Available with KVM_CAP_PPC_GET_PVINFO */ #define KVM_PPC_GET_PVINFO _IOW(KVMIO, 0xa1, struct kvm_ppc_pvinfo) +/* Available with KVM_CAP_TSC_CONTROL */ +#define KVM_SET_TSC_KHZ _IOW(KVMIO, 0xa2, __u32) +#define KVM_GET_TSC_KHZ _IOR(KVMIO, 0xa2, __u32) /* * ioctls for vcpu fds -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
