| Message ID | 1552431636-31511-12-git-send-email-fenghua.yu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/split_lock: Enable #AC exception for split locked accesses | expand |
On 13/03/19 00:00, Fenghua Yu wrote: > From: Xiaoyao Li <xiaoyao.li@linux.intel.com> > > A control bit (bit 29) in TEST_CTL MSR 0x33 will be introduced in > future x86 processors. When bit 29 is set, the processor causes #AC > exception for split locked accesses at all CPL. > > Please check the latest Intel 64 and IA-32 Architectures Software > Developer's Manual for more detailed information on the MSR and > the split lock bit. > > This patch emulate MSR TEST_CTL with vmx->msr_test_ctl and does the > following: > 1. As we emulate MSR TEST_CTL of guest, we should enable the related bits > in CORE_CAPABILITY to corretly report this feature to guest. > > 2. Differentiate MSR TEST_CTL between host and guest. > > Signed-off-by: Xiaoyao Li <xiaoyao.li@linux.intel.com> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> > --- > arch/x86/kvm/vmx/vmx.c | 35 +++++++++++++++++++++++++++++++++++ > arch/x86/kvm/vmx/vmx.h | 1 + > arch/x86/kvm/x86.c | 17 ++++++++++++++++- > 3 files changed, 52 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 30a6bcd735ec..270c6566fd5a 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -1659,6 +1659,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > u32 index; > > switch (msr_info->index) { > + case MSR_TEST_CTL: > + if (!msr_info->host_initiated && > + !(vcpu->arch.core_capability & CORE_CAP_SPLIT_LOCK_DETECT)) > + return 1; > + msr_info->data = vmx->msr_test_ctl; > + break; > #ifdef CONFIG_X86_64 > case MSR_FS_BASE: > msr_info->data = vmcs_readl(GUEST_FS_BASE); > @@ -1799,6 +1805,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > u32 index; > > switch (msr_index) { > + case MSR_TEST_CTL: > + if (!(vcpu->arch.core_capability & CORE_CAP_SPLIT_LOCK_DETECT)) > + return 1; > + > + if (data & ~TEST_CTL_ENABLE_SPLIT_LOCK_DETECT) > + return 1; > + vmx->msr_test_ctl = data; > + break; > case MSR_EFER: > ret = kvm_set_msr_common(vcpu, msr_info); > break; > @@ -4085,6 +4099,9 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) > > vmx->arch_capabilities = kvm_get_arch_capabilities(); > > + /* disable AC split lock by default */ > + vmx->msr_test_ctl = 0; > + > vm_exit_controls_init(vmx, vmx_vmexit_ctrl()); > > /* 22.2.1, 20.8.1 */ > @@ -4122,6 +4139,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > > vmx->rmode.vm86_active = 0; > vmx->spec_ctrl = 0; > + vmx->msr_test_ctl = 0; > > vcpu->arch.microcode_version = 0x100000000ULL; > vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val(); > @@ -6321,6 +6339,21 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) > msrs[i].host, false); > } > > +static void atomic_switch_msr_test_ctl(struct vcpu_vmx *vmx) > +{ > + u64 host_msr_test_ctl; > + > + /* if TEST_CTL MSR doesn't exist on the hardware, we do nothing */ > + if (rdmsrl_safe(MSR_TEST_CTL, &host_msr_test_ctl)) > + return; > + > + if (host_msr_test_ctl == vmx->msr_test_ctl) > + clear_atomic_switch_msr(vmx, MSR_TEST_CTL); > + else > + add_atomic_switch_msr(vmx, MSR_TEST_CTL, vmx->msr_test_ctl, > + host_msr_test_ctl, false); > +} > + > static void vmx_arm_hv_timer(struct vcpu_vmx *vmx, u32 val) > { > vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, val); > @@ -6562,6 +6595,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) > > atomic_switch_perf_msrs(vmx); > > + atomic_switch_msr_test_ctl(vmx); > + > vmx_update_hv_timer(vcpu); > > /* > diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h > index 0ac0a64c7790..8549cba0fb75 100644 > --- a/arch/x86/kvm/vmx/vmx.h > +++ b/arch/x86/kvm/vmx/vmx.h > @@ -191,6 +191,7 @@ struct vcpu_vmx { > u64 msr_guest_kernel_gs_base; > #endif > > + u64 msr_test_ctl; > u64 arch_capabilities; > u64 spec_ctrl; > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index e20cbb8c2b74..ad1df965574e 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1228,7 +1228,22 @@ EXPORT_SYMBOL_GPL(kvm_get_arch_capabilities); > > u64 kvm_get_core_capability(void) > { > - return 0; > + u64 data; > + > + rdmsrl_safe(MSR_IA32_CORE_CAPABILITY, &data); > + > + /* mask non-virtualizable functions */ > + data &= CORE_CAP_SPLIT_LOCK_DETECT; > + > + /* > + * There will be a list of FMS values that have split lock detection > + * but lack the CORE CAPABILITY MSR. In this case, we can set > + * CORE_CAP_SPLIT_LOCK_DETECT since we emulate MSR CORE_CAPABILITY. > + */ > + if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) > + data |= CORE_CAP_SPLIT_LOCK_DETECT; > + > + return data; > } > EXPORT_SYMBOL_GPL(kvm_get_core_capability); > > Acked-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 30a6bcd735ec..270c6566fd5a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1659,6 +1659,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) u32 index; switch (msr_info->index) { + case MSR_TEST_CTL: + if (!msr_info->host_initiated && + !(vcpu->arch.core_capability & CORE_CAP_SPLIT_LOCK_DETECT)) + return 1; + msr_info->data = vmx->msr_test_ctl; + break; #ifdef CONFIG_X86_64 case MSR_FS_BASE: msr_info->data = vmcs_readl(GUEST_FS_BASE); @@ -1799,6 +1805,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) u32 index; switch (msr_index) { + case MSR_TEST_CTL: + if (!(vcpu->arch.core_capability & CORE_CAP_SPLIT_LOCK_DETECT)) + return 1; + + if (data & ~TEST_CTL_ENABLE_SPLIT_LOCK_DETECT) + return 1; + vmx->msr_test_ctl = data; + break; case MSR_EFER: ret = kvm_set_msr_common(vcpu, msr_info); break; @@ -4085,6 +4099,9 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) vmx->arch_capabilities = kvm_get_arch_capabilities(); + /* disable AC split lock by default */ + vmx->msr_test_ctl = 0; + vm_exit_controls_init(vmx, vmx_vmexit_ctrl()); /* 22.2.1, 20.8.1 */ @@ -4122,6 +4139,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) vmx->rmode.vm86_active = 0; vmx->spec_ctrl = 0; + vmx->msr_test_ctl = 0; vcpu->arch.microcode_version = 0x100000000ULL; vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val(); @@ -6321,6 +6339,21 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) msrs[i].host, false); } +static void atomic_switch_msr_test_ctl(struct vcpu_vmx *vmx) +{ + u64 host_msr_test_ctl; + + /* if TEST_CTL MSR doesn't exist on the hardware, we do nothing */ + if (rdmsrl_safe(MSR_TEST_CTL, &host_msr_test_ctl)) + return; + + if (host_msr_test_ctl == vmx->msr_test_ctl) + clear_atomic_switch_msr(vmx, MSR_TEST_CTL); + else + add_atomic_switch_msr(vmx, MSR_TEST_CTL, vmx->msr_test_ctl, + host_msr_test_ctl, false); +} + static void vmx_arm_hv_timer(struct vcpu_vmx *vmx, u32 val) { vmcs_write32(VMX_PREEMPTION_TIMER_VALUE, val); @@ -6562,6 +6595,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) atomic_switch_perf_msrs(vmx); + atomic_switch_msr_test_ctl(vmx); + vmx_update_hv_timer(vcpu); /* diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 0ac0a64c7790..8549cba0fb75 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -191,6 +191,7 @@ struct vcpu_vmx { u64 msr_guest_kernel_gs_base; #endif + u64 msr_test_ctl; u64 arch_capabilities; u64 spec_ctrl; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e20cbb8c2b74..ad1df965574e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1228,7 +1228,22 @@ EXPORT_SYMBOL_GPL(kvm_get_arch_capabilities); u64 kvm_get_core_capability(void) { - return 0; + u64 data; + + rdmsrl_safe(MSR_IA32_CORE_CAPABILITY, &data); + + /* mask non-virtualizable functions */ + data &= CORE_CAP_SPLIT_LOCK_DETECT; + + /* + * There will be a list of FMS values that have split lock detection + * but lack the CORE CAPABILITY MSR. In this case, we can set + * CORE_CAP_SPLIT_LOCK_DETECT since we emulate MSR CORE_CAPABILITY. + */ + if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) + data |= CORE_CAP_SPLIT_LOCK_DETECT; + + return data; } EXPORT_SYMBOL_GPL(kvm_get_core_capability);