KVM: x86: do not spam dmesg with VMCS/VMCB dumps
Userspace can easily set up invalid processor state in such a way that dmesg will be filled with VMCS or VMCB dumps. Disable this by default using a module parameter. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -379,6 +379,9 @@ module_param(vgif, int, 0444);
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static int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
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module_param(sev, int, 0444);
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static bool __read_mostly dump_invalid_vmcb = 0;
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module_param(dump_invalid_vmcb, bool, 0644);
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static u8 rsm_ins_bytes[] = "\x0f\xaa";
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static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
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@ -4828,6 +4831,11 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
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struct vmcb_control_area *control = &svm->vmcb->control;
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struct vmcb_save_area *save = &svm->vmcb->save;
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if (!dump_invalid_vmcb) {
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pr_warn_ratelimited("set kvm_amd.dump_invalid_vmcb=1 to dump internal KVM state.\n");
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return;
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}
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pr_err("VMCB Control Area:\n");
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pr_err("%-20s%04x\n", "cr_read:", control->intercept_cr & 0xffff);
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pr_err("%-20s%04x\n", "cr_write:", control->intercept_cr >> 16);
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@ -4986,7 +4994,6 @@ static int handle_exit(struct kvm_vcpu *vcpu)
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kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
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kvm_run->fail_entry.hardware_entry_failure_reason
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= svm->vmcb->control.exit_code;
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pr_err("KVM: FAILED VMRUN WITH VMCB:\n");
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dump_vmcb(vcpu);
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return 0;
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}
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@ -114,6 +114,9 @@ static u64 __read_mostly host_xss;
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bool __read_mostly enable_pml = 1;
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module_param_named(pml, enable_pml, bool, S_IRUGO);
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static bool __read_mostly dump_invalid_vmcs = 0;
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module_param(dump_invalid_vmcs, bool, 0644);
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#define MSR_BITMAP_MODE_X2APIC 1
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#define MSR_BITMAP_MODE_X2APIC_APICV 2
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@ -5607,15 +5610,24 @@ static void vmx_dump_dtsel(char *name, uint32_t limit)
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void dump_vmcs(void)
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{
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u32 vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS);
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u32 vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS);
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u32 cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
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u32 pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);
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u32 secondary_exec_control = 0;
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unsigned long cr4 = vmcs_readl(GUEST_CR4);
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u64 efer = vmcs_read64(GUEST_IA32_EFER);
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u32 vmentry_ctl, vmexit_ctl;
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u32 cpu_based_exec_ctrl, pin_based_exec_ctrl, secondary_exec_control;
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unsigned long cr4;
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u64 efer;
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int i, n;
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if (!dump_invalid_vmcs) {
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pr_warn_ratelimited("set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.\n");
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return;
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}
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vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS);
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vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS);
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cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
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pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);
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cr4 = vmcs_readl(GUEST_CR4);
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efer = vmcs_read64(GUEST_IA32_EFER);
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secondary_exec_control = 0;
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if (cpu_has_secondary_exec_ctrls())
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secondary_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
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