Re: [PATCH 00/12] KVM: x86: add support for VMX TSC scaling
On Mon, Sep 28, 2015 at 09:00:39PM -0700, Eric Northup wrote: > On Sun, Sep 27, 2015 at 10:37 PM, 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 scaling 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. > > reviewed-by: Eric Northup > Thank you for the review! > > > > 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 | 4 +- > > arch/x86/kvm/lapic.c| 5 +- > > arch/x86/kvm/svm.c | 113 +++-- > > arch/x86/kvm/vmx.c | 60 > > arch/x86/kvm/x86.c | 154 > > +--- > > include/linux/kvm_host.h| 21 +- > > 7 files changed, 221 insertions(+), 160 deletions(-) > > > > -- > > 2.4.8 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe kvm" in > > the body of a message to majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 00/12] KVM: x86: add support for VMX TSC scaling
On Sun, Sep 27, 2015 at 10:37 PM, 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 scaling 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. reviewed-by: Eric Northup > > 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 | 4 +- > arch/x86/kvm/lapic.c| 5 +- > arch/x86/kvm/svm.c | 113 +++-- > arch/x86/kvm/vmx.c | 60 > arch/x86/kvm/x86.c | 154 > +--- > include/linux/kvm_host.h| 21 +- > 7 files changed, 221 insertions(+), 160 deletions(-) > > -- > 2.4.8 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 00/12] KVM: x86: add support for VMX TSC scaling
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 scaling 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. 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 | 4 +- arch/x86/kvm/lapic.c| 5 +- arch/x86/kvm/svm.c | 113 +++-- arch/x86/kvm/vmx.c | 60 arch/x86/kvm/x86.c | 154 +--- include/linux/kvm_host.h| 21 +- 7 files changed, 221 insertions(+), 160 deletions(-) -- 2.4.8 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
