Commit 6f2f8453 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 654f1f13

arch/x86/kvm/svm.c

+8 −1
Original line number Diff line number Diff line
@@ -379,6 +379,9 @@ module_param(vgif, int, 0444); 
static int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);

module_param(sev, int, 0444);



static bool __read_mostly dump_invalid_vmcb = 0;

module_param(dump_invalid_vmcb, bool, 0644);



static u8 rsm_ins_bytes[] = "\x0f\xaa";



static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
@@ -4828,6 +4831,11 @@ static void dump_vmcb(struct kvm_vcpu *vcpu) 
	struct vmcb_control_area *control = &svm->vmcb->control;

	struct vmcb_save_area *save = &svm->vmcb->save;



	if (!dump_invalid_vmcb) {

		pr_warn_ratelimited("set kvm_amd.dump_invalid_vmcb=1 to dump internal KVM state.\n");

		return;

	}



	pr_err("VMCB Control Area:\n");

	pr_err("%-20s%04x\n", "cr_read:", control->intercept_cr & 0xffff);

	pr_err("%-20s%04x\n", "cr_write:", control->intercept_cr >> 16);
@@ -4986,7 +4994,6 @@ static int handle_exit(struct kvm_vcpu *vcpu) 
		kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;

		kvm_run->fail_entry.hardware_entry_failure_reason

			= svm->vmcb->control.exit_code;

		pr_err("KVM: FAILED VMRUN WITH VMCB:\n");

		dump_vmcb(vcpu);

		return 0;

	}

arch/x86/kvm/vmx/vmx.c

+19 −7
Original line number Diff line number Diff line
@@ -114,6 +114,9 @@ static u64 __read_mostly host_xss; 
bool __read_mostly enable_pml = 1;

module_param_named(pml, enable_pml, bool, S_IRUGO);



static bool __read_mostly dump_invalid_vmcs = 0;

module_param(dump_invalid_vmcs, bool, 0644);



#define MSR_BITMAP_MODE_X2APIC		1

#define MSR_BITMAP_MODE_X2APIC_APICV	2
@@ -5607,15 +5610,24 @@ static void vmx_dump_dtsel(char *name, uint32_t limit) 


void dump_vmcs(void)

{

	u32 vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS);

	u32 vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS);

	u32 cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);

	u32 pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);

	u32 secondary_exec_control = 0;

	unsigned long cr4 = vmcs_readl(GUEST_CR4);

	u64 efer = vmcs_read64(GUEST_IA32_EFER);

	u32 vmentry_ctl, vmexit_ctl;

	u32 cpu_based_exec_ctrl, pin_based_exec_ctrl, secondary_exec_control;

	unsigned long cr4;

	u64 efer;

	int i, n;



	if (!dump_invalid_vmcs) {

		pr_warn_ratelimited("set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.\n");

		return;

	}



	vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS);

	vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS);

	cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);

	pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);

	cr4 = vmcs_readl(GUEST_CR4);

	efer = vmcs_read64(GUEST_IA32_EFER);

	secondary_exec_control = 0;

	if (cpu_has_secondary_exec_ctrls())

		secondary_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);