From: Tao Xu <tao3.xu@intel.com> To: Sean Christopherson <sean.j.christopherson@intel.com> Cc: pbonzini@redhat.com, rkrcmar@redhat.com, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, fenghua.yu@intel.com, xiaoyao.li@linux.intel.com, jingqi.liu@intel.com Subject: Re: [PATCH v7 2/3] KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL Date: Mon, 15 Jul 2019 09:22:14 +0800 Message-ID: <8ed3cec5-8ba9-b2ed-f0e4-eefb0a988bc8@intel.com> (raw) In-Reply-To: <20190712155202.GC29659@linux.intel.com> On 7/12/2019 11:52 PM, Sean Christopherson wrote: > On Fri, Jul 12, 2019 at 04:29:06PM +0800, Tao Xu wrote: >> diff --git a/arch/x86/kernel/cpu/umwait.c b/arch/x86/kernel/cpu/umwait.c >> index 6a204e7336c1..631152a67c6e 100644 >> --- a/arch/x86/kernel/cpu/umwait.c >> +++ b/arch/x86/kernel/cpu/umwait.c >> @@ -15,7 +15,8 @@ >> * Cache IA32_UMWAIT_CONTROL MSR. This is a systemwide control. By default, >> * umwait max time is 100000 in TSC-quanta and C0.2 is enabled >> */ >> -static u32 umwait_control_cached = UMWAIT_CTRL_VAL(100000, UMWAIT_C02_ENABLE); >> +u32 umwait_control_cached = UMWAIT_CTRL_VAL(100000, UMWAIT_C02_ENABLE); >> +EXPORT_SYMBOL_GPL(umwait_control_cached); > > It'd probably be better to add an accessor to expose umwait_control_cached > given that umwait.c is using {READ,WRITE}_ONCE() and there shouldn't be a > need to write it outside of umwait.c. > OKay >> /* >> * Serialize access to umwait_control_cached and IA32_UMWAIT_CONTROL MSR in >> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c >> index f411c9ae5589..0787f140d155 100644 >> --- a/arch/x86/kvm/vmx/vmx.c >> +++ b/arch/x86/kvm/vmx/vmx.c >> @@ -1676,6 +1676,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> #endif >> case MSR_EFER: >> return kvm_get_msr_common(vcpu, msr_info); >> + case MSR_IA32_UMWAIT_CONTROL: >> + if (!msr_info->host_initiated && !vmx_has_waitpkg(vmx)) >> + return 1; >> + >> + msr_info->data = vmx->msr_ia32_umwait_control; >> + break; >> case MSR_IA32_SPEC_CTRL: >> if (!msr_info->host_initiated && >> !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL)) >> @@ -1838,6 +1844,16 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> return 1; >> vmcs_write64(GUEST_BNDCFGS, data); >> break; >> + case MSR_IA32_UMWAIT_CONTROL: >> + if (!msr_info->host_initiated && !vmx_has_waitpkg(vmx)) >> + return 1; >> + >> + /* The reserved bit IA32_UMWAIT_CONTROL[1] should be zero */ >> + if (data & BIT_ULL(1)) >> + return 1; >> + >> + vmx->msr_ia32_umwait_control = data; > > The SDM only defines bits 31:0, and the kernel uses a u32 to cache its > value. I assume bits 63:32 are reserved? I'm guessing we also need an > SDM update... > The SDM define IA32_UMWAIT_CONTROL is a 32bit MSR. So need me to set 63:32 reserved? >> + break; >> case MSR_IA32_SPEC_CTRL: >> if (!msr_info->host_initiated && >> !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL)) >> @@ -4139,6 +4155,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) >> vmx->rmode.vm86_active = 0; >> vmx->spec_ctrl = 0; >> >> + vmx->msr_ia32_umwait_control = 0; >> + >> vcpu->arch.microcode_version = 0x100000000ULL; >> vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val(); >> kvm_set_cr8(vcpu, 0); >> @@ -6352,6 +6370,19 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) >> msrs[i].host, false); >> } >>
next prev parent reply index Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-12 8:29 [PATCH v7 0/3] KVM: x86: Enable user wait instructions Tao Xu 2019-07-12 8:29 ` [PATCH v7 1/3] KVM: x86: add support for " Tao Xu 2019-07-12 15:13 ` Sean Christopherson 2019-07-15 1:11 ` Tao Xu 2019-07-12 8:29 ` [PATCH v7 2/3] KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL Tao Xu 2019-07-12 15:52 ` Sean Christopherson 2019-07-15 1:22 ` Tao Xu [this message] 2019-07-15 14:16 ` Sean Christopherson 2019-07-16 16:03 ` Eduardo Habkost 2019-07-17 1:17 ` Tao Xu 2019-07-17 2:03 ` Tao Xu 2019-07-12 8:29 ` [PATCH v7 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE Tao Xu 2019-07-12 16:03 ` Sean Christopherson 2019-07-13 14:22 ` Tao Xu
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