[PATCH v2 31/50] KVM: x86: Do CPU compatibility checks in x86 code
From: Sean Christopherson <seanjc@google.com>
Date: 2022-11-30 23:14:53
Also in:
kvm, kvm-riscv, kvmarm, linux-arm-kernel, linux-mips, linux-riscv, linux-s390, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Move the CPU compatibility checks to pure x86 code, i.e. drop x86's use of the common kvm_x86_check_cpu_compat() arch hook. x86 is the only architecture that "needs" to do per-CPU compatibility checks, moving the logic to x86 will allow dropping the common code, and will also give x86 more control over when/how the compatibility checks are performed, e.g. TDX will need to enable hardware (do VMXON) in order to perform compatibility checks. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/svm/svm.c | 2 +- arch/x86/kvm/vmx/vmx.c | 2 +- arch/x86/kvm/x86.c | 49 ++++++++++++++++++++++++++++++++---------- 3 files changed, 40 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 19e81a99c58f..d7ea1c1175c2 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c@@ -5103,7 +5103,7 @@ static int __init svm_init(void) * Common KVM initialization _must_ come last, after this, /dev/kvm is * exposed to userspace! */ - r = kvm_init(&svm_init_ops, sizeof(struct vcpu_svm), + r = kvm_init(NULL, sizeof(struct vcpu_svm), __alignof__(struct vcpu_svm), THIS_MODULE); if (r) goto err_kvm_init;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 654d81f781da..8deb1bd60c10 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c@@ -8592,7 +8592,7 @@ static int __init vmx_init(void) * Common KVM initialization _must_ come last, after this, /dev/kvm is * exposed to userspace! */ - r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx), + r = kvm_init(NULL, sizeof(struct vcpu_vmx), __alignof__(struct vcpu_vmx), THIS_MODULE); if (r) goto err_kvm_init;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 66f16458aa97..3571bc968cf8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c@@ -9277,10 +9277,36 @@ static inline void kvm_ops_update(struct kvm_x86_init_ops *ops) kvm_pmu_ops_update(ops->pmu_ops); } +struct kvm_cpu_compat_check { + struct kvm_x86_init_ops *ops; + int *ret; +}; + +static int kvm_x86_check_processor_compatibility(struct kvm_x86_init_ops *ops) +{ + struct cpuinfo_x86 *c = &cpu_data(smp_processor_id()); + + WARN_ON(!irqs_disabled()); + + if (__cr4_reserved_bits(cpu_has, c) != + __cr4_reserved_bits(cpu_has, &boot_cpu_data)) + return -EIO; + + return ops->check_processor_compatibility(); +} + +static void kvm_x86_check_cpu_compat(void *data) +{ + struct kvm_cpu_compat_check *c = data; + + *c->ret = kvm_x86_check_processor_compatibility(c->ops); +} + static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) { + struct kvm_cpu_compat_check c; u64 host_pat; - int r; + int r, cpu; if (kvm_x86_ops.hardware_enable) { pr_err("kvm: already loaded vendor module '%s'\n", kvm_x86_ops.name);
@@ -9360,6 +9386,14 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) if (r != 0) goto out_mmu_exit; + c.ret = &r; + c.ops = ops; + for_each_online_cpu(cpu) { + smp_call_function_single(cpu, kvm_x86_check_cpu_compat, &c, 1); + if (r < 0) + goto out_hardware_unsetup; + } + /* * Point of no return! DO NOT add error paths below this point unless * absolutely necessary, as most operations from this point forward
@@ -9402,6 +9436,8 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) kvm_init_msr_list(); return 0; +out_hardware_unsetup: + ops->runtime_ops->hardware_unsetup(); out_mmu_exit: kvm_mmu_vendor_module_exit(); out_free_percpu:
@@ -12037,16 +12073,7 @@ void kvm_arch_hardware_disable(void) int kvm_arch_check_processor_compat(void *opaque) { - struct cpuinfo_x86 *c = &cpu_data(smp_processor_id()); - struct kvm_x86_init_ops *ops = opaque; - - WARN_ON(!irqs_disabled()); - - if (__cr4_reserved_bits(cpu_has, c) != - __cr4_reserved_bits(cpu_has, &boot_cpu_data)) - return -EIO; - - return ops->check_processor_compatibility(); + return 0; } bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu)
--
2.38.1.584.g0f3c55d4c2-goog