From c82a5c5c53c5b732a9610736841a117373e43adb Mon Sep 17 00:00:00 2001 From: Chao Gao Date: Wed, 30 Nov 2022 23:09:24 +0000 Subject: [PATCH] KVM: x86: Do compatibility checks when onlining CPU Do compatibility checks when enabling hardware to effectively add compatibility checks when onlining a CPU. Abort enabling, i.e. the online process, if the (hotplugged) CPU is incompatible with the known good setup. At init time, KVM does compatibility checks to ensure that all online CPUs support hardware virtualization and a common set of features. But KVM uses hotplugged CPUs without such compatibility checks. On Intel CPUs, this leads to #GP if the hotplugged CPU doesn't support VMX, or VM-Entry failure if the hotplugged CPU doesn't support all features enabled by KVM. Note, this is little more than a NOP on SVM, as SVM already checks for full SVM support during hardware enabling. Opportunistically add a pr_err() if setup_vmcs_config() fails, and tweak all error messages to output which CPU failed. Signed-off-by: Chao Gao Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Acked-by: Kai Huang Message-Id: <20221130230934.1014142-41-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/svm.c | 8 +++----- arch/x86/kvm/vmx/vmx.c | 15 ++++++++++----- arch/x86/kvm/x86.c | 5 +++++ 3 files changed, 18 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b106cbb24c4d..799b24801d31 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -521,11 +521,12 @@ static void svm_init_osvw(struct kvm_vcpu *vcpu) static bool kvm_is_svm_supported(void) { + int cpu = raw_smp_processor_id(); const char *msg; u64 vm_cr; if (!cpu_has_svm(&msg)) { - pr_err("SVM not supported, %s\n", msg); + pr_err("SVM not supported by CPU %d, %s\n", cpu, msg); return false; } @@ -536,7 +537,7 @@ static bool kvm_is_svm_supported(void) rdmsrl(MSR_VM_CR, vm_cr); if (vm_cr & (1 << SVM_VM_CR_SVM_DISABLE)) { - pr_err("SVM disabled (by BIOS) in MSR_VM_CR\n"); + pr_err("SVM disabled (by BIOS) in MSR_VM_CR on CPU %d\n", cpu); return false; } @@ -587,9 +588,6 @@ static int svm_hardware_enable(void) if (efer & EFER_SVME) return -EBUSY; - if (!kvm_is_svm_supported()) - return -EINVAL; - sd = per_cpu_ptr(&svm_data, me); sd->asid_generation = 1; sd->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 3d5e93ceed6b..73005d7e4e43 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2747,14 +2747,16 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf, static bool kvm_is_vmx_supported(void) { + int cpu = raw_smp_processor_id(); + if (!cpu_has_vmx()) { - pr_err("CPU doesn't support VMX\n"); + pr_err("VMX not supported by CPU %d\n", cpu); return false; } if (!this_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) || !this_cpu_has(X86_FEATURE_VMX)) { - pr_err("VMX not enabled (by BIOS) in MSR_IA32_FEAT_CTL\n"); + pr_err("VMX not enabled (by BIOS) in MSR_IA32_FEAT_CTL on CPU %d\n", cpu); return false; } @@ -2763,18 +2765,21 @@ static bool kvm_is_vmx_supported(void) static int vmx_check_processor_compat(void) { + int cpu = raw_smp_processor_id(); struct vmcs_config vmcs_conf; struct vmx_capability vmx_cap; if (!kvm_is_vmx_supported()) return -EIO; - if (setup_vmcs_config(&vmcs_conf, &vmx_cap) < 0) + if (setup_vmcs_config(&vmcs_conf, &vmx_cap) < 0) { + pr_err("Failed to setup VMCS config on CPU %d\n", cpu); return -EIO; + } if (nested) nested_vmx_setup_ctls_msrs(&vmcs_conf, vmx_cap.ept); - if (memcmp(&vmcs_config, &vmcs_conf, sizeof(struct vmcs_config)) != 0) { - pr_err("CPU %d feature inconsistency!\n", smp_processor_id()); + if (memcmp(&vmcs_config, &vmcs_conf, sizeof(struct vmcs_config))) { + pr_err("Inconsistent VMCS config on CPU %d\n", cpu); return -EIO; } return 0; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9870a746364f..6575d9e7b9b6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11980,6 +11980,11 @@ int kvm_arch_hardware_enable(void) bool stable, backwards_tsc = false; kvm_user_return_msr_cpu_online(); + + ret = kvm_x86_check_processor_compatibility(); + if (ret) + return ret; + ret = static_call(kvm_x86_hardware_enable)(); if (ret != 0) return ret;