diff options
| author | Joerg Roedel | 2011-03-25 09:44:51 +0100 |
|---|---|---|
| committer | Avi Kivity | 2011-05-11 07:57:06 -0400 |
| commit | 92a1f12d2598f429bd8639e21d89305e787115c5 (patch) | |
| tree | 48a6b7d6c50b5583b5163185dd097db100a471c6 /arch/x86/kvm/svm.c | |
| parent | 857e40999e35906baa367a79137019912cfb5434 (diff) | |
KVM: X86: Implement userspace interface to set virtual_tsc_khz
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 <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 8c4549bef4ed..a98873762433 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; @@ -189,6 +191,7 @@ 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, @@ -798,6 +801,23 @@ 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 max; + + kvm_has_tsc_control = true; + + /* + * Make sure the user can only configure tsc_khz values that + * fit into a signed integer. + * A min value is not calculated needed because it will always + * be 1 on all machines and a value of 0 is used to disable + * tsc-scaling for the vcpu. + */ + max = min(0x7fffffffULL, __scale_tsc(tsc_khz, TSC_RATIO_MAX)); + + kvm_max_guest_tsc_khz = max; + } + if (nested) { printk(KERN_INFO "kvm: Nested Virtualization enabled\n"); kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE); |