[ Upstream commit 6f2f84532c153d32a5e53b6083b06a3e24368d30 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kvm/svm.c | 9 ++++++++- arch/x86/kvm/vmx/vmx.c | 26 +++++++++++++++++++------- 2 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index ae6e51828a54..aa3b77acfbf9 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -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); @@ -4834,6 +4837,11 @@ 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); @@ -4992,7 +5000,6 @@ 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; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 2b4a3d32c511..cfb8f1ec9a0a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -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
@@ -5605,15 +5608,24 @@ 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);