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KVM: X86: Implement call-back to propagate virtual_tsc_khz

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This patch implements a call-back into the architecture code
to allow the propagation of changes to the virtual tsc_khz
of the vcpu.
On SVM it updates the tsc_ratio variable, on VMX it does
nothing.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Joerg Roedel
2011-03-25 09:44:49 +01:00
committed by Avi Kivity
parent 8f6055cbaf
commit 4051b18801
3 changed files with 45 additions and 0 deletions
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33
arch/x86/kvm/svm.c
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@@ -885,6 +885,38 @@ static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
return _tsc;
}
static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
{
struct vcpu_svm *svm = to_svm(vcpu);
u64 ratio;
u64 khz;
/* TSC scaling supported? */
if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR))
return;
/* TSC-Scaling disabled or guest TSC same frequency as host TSC? */
if (user_tsc_khz == 0) {
vcpu->arch.virtual_tsc_khz = 0;
svm->tsc_ratio = TSC_RATIO_DEFAULT;
return;
}
khz = user_tsc_khz;
/* TSC scaling required - calculate ratio */
ratio = khz << 32;
do_div(ratio, tsc_khz);
if (ratio == 0 || ratio & TSC_RATIO_RSVD) {
WARN_ONCE(1, "Invalid TSC ratio - virtual-tsc-khz=%u\n",
user_tsc_khz);
return;
}
vcpu->arch.virtual_tsc_khz = user_tsc_khz;
svm->tsc_ratio = ratio;
}
static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -4159,6 +4191,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.has_wbinvd_exit = svm_has_wbinvd_exit,
.set_tsc_khz = svm_set_tsc_khz,
.write_tsc_offset = svm_write_tsc_offset,
.adjust_tsc_offset = svm_adjust_tsc_offset,