On 20/10/2015 09:39, Haozhong Zhang wrote: > This patchset adds support for VMX TSC scaling feature which is > available on Intel Skylake CPU. The specification of VMX TSC scaling > can be found at > http://www.intel.com/content/www/us/en/processors/timestamp-counter-scaling-virtualization-white-paper.html > > VMX TSC scaling allows guest TSC which is read by guest rdtsc(p) > instructions increases in a rate that is customized by the hypervisor > and can be different than the host TSC rate. Basically, VMX TSC > scaling adds a 64-bit field called TSC multiplier in VMCS so that, if > VMX TSC scaling is enabled, TSC read by guest rdtsc(p) instructions > will be calculated by the following formula: > > guest EDX:EAX = (Host TSC * TSC multiplier) >> 48 + VMX TSC Offset > > where, Host TSC = Host MSR_IA32_TSC + Host MSR_IA32_TSC_ADJUST. > > This patchset, when cooperating with another QEMU patchset (sent in > another email "target-i386: save/restore vcpu's TSC rate during > migration"), allows guest programs observe a consistent TSC rate even > though they are migrated among machines with different host TSC rates. > > VMX TSC scaling shares some common logics with SVM TSC ratio which > is already supported by KVM. Patch 1 ~ 8 move those common logics from > SVM code to the common code. Upon them, patch 9 ~ 12 add VMX-specific > support for VMX TSC scaling. > > Changes in v2: > * Remove the duplicated variable 'kvm_tsc_scaling_ratio_rsvd'. > * Remove an unnecessary error check in original patch 2. > * Do 64-bit arithmetic by functions recommended by Paolo. > * Make kvm_set_tsc_khz() returns an error number so that ioctl > KVM_SET_TSC_KHZ does not return 0 if errors happen. > > Reviewed-by: Eric Northup <digitaleric@xxxxxxxxxx> Thanks for the patches. There are a couple changes that I can do myself: 1) kvm_default_tsc_scaling_ratio can be initialized in kvm_arch_hardware_setup, since it's just 1ULL << kvm_tsc_scaling_ratio_frac_bits 2) things that you are adding to include/linux/kvm_host.h should instead go in arch/x86/include/linux/kvm_host.h That's it. I'll commit it as soon as I test on AMD (today hopefully). Paolo > Haozhong Zhang (12): > KVM: x86: Collect information for setting TSC scaling ratio > KVM: x86: Add a common TSC scaling ratio field in kvm_vcpu_arch > KVM: x86: Add a common TSC scaling function > KVM: x86: Replace call-back set_tsc_khz() with a common function > KVM: x86: Replace call-back compute_tsc_offset() with a common function > KVM: x86: Move TSC scaling logic out of call-back adjust_tsc_offset() > KVM: x86: Move TSC scaling logic out of call-back read_l1_tsc() > KVM: x86: Use the correct vcpu's TSC rate to compute time scale > KVM: VMX: Enable and initialize VMX TSC scaling > KVM: VMX: Setup TSC scaling ratio when a vcpu is loaded > KVM: VMX: Use a scaled host TSC for guest readings of MSR_IA32_TSC > KVM: VMX: Dump TSC multiplier in dump_vmcs() > > arch/x86/include/asm/kvm_host.h | 24 +++---- > arch/x86/include/asm/vmx.h | 3 + > arch/x86/kvm/lapic.c | 4 +- > arch/x86/kvm/svm.c | 116 ++++------------------------------ > arch/x86/kvm/vmx.c | 64 ++++++++++--------- > arch/x86/kvm/x86.c | 134 +++++++++++++++++++++++++++++++++++----- > include/linux/kvm_host.h | 20 ++++++ > include/linux/math64.h | 99 +++++++++++++++++++++++++++++ > 8 files changed, 297 insertions(+), 167 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
