Commit 1d15ffdf authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

KVM: PPC: Book3S HV: Ratelimit machine check messages coming from guests 



A number of machine check exceptions are triggerable by the guest.
Ratelimit these to avoid a guest flooding the host console and logs.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
[mpe: Use dedicated ratelimit state, not printk_ratelimit()]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201128070728.825934-5-npiggin@gmail.com
parent 067c9f9c

arch/powerpc/kvm/book3s_hv.c

+16 −4
Original line number Diff line number Diff line
@@ -1327,8 +1327,14 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu, 
	case BOOK3S_INTERRUPT_SYSTEM_RESET:

		r = RESUME_GUEST;

		break;

	case BOOK3S_INTERRUPT_MACHINE_CHECK:

		/* Print the MCE event to host console. */

	case BOOK3S_INTERRUPT_MACHINE_CHECK: {

		static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,

					      DEFAULT_RATELIMIT_BURST);

		/*

		 * Print the MCE event to host console. Ratelimit so the guest

		 * can't flood the host log.

		 */

		if (__ratelimit(&rs))

			machine_check_print_event_info(&vcpu->arch.mce_evt,false, true);



		/*
@@ -1357,6 +1363,7 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu, 


		r = RESUME_HOST;

		break;

	}

	case BOOK3S_INTERRUPT_PROGRAM:

	{

		ulong flags;
@@ -1516,11 +1523,16 @@ static int kvmppc_handle_nested_exit(struct kvm_vcpu *vcpu) 
		r = RESUME_GUEST;

		break;

	case BOOK3S_INTERRUPT_MACHINE_CHECK:

	{

		static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,

					      DEFAULT_RATELIMIT_BURST);

		/* Pass the machine check to the L1 guest */

		r = RESUME_HOST;

		/* Print the MCE event to host console. */

		if (__ratelimit(&rs))

			machine_check_print_event_info(&vcpu->arch.mce_evt, false, true);

		break;

	}

	/*

	 * We get these next two if the guest accesses a page which it thinks

	 * it has mapped but which is not actually present, either because

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