From abf532cceaca9c21a148498091f87de1b8ae9b49 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Mon, 3 Aug 2020 13:31:25 -0600 Subject: [PATCH] KVM: arm64: Print warning when cpu erratum can cause guests to deadlock If guests don't have certain CPU erratum workarounds implemented, then there is a possibility a guest can deadlock the system. IOW, only trusted guests should be used on systems with the erratum. This is the case for Cortex-A57 erratum 832075. Signed-off-by: Rob Herring Acked-by: Will Deacon Cc: Marc Zyngier Cc: James Morse Cc: Julien Thierry Cc: Suzuki K Poulose Cc: Will Deacon Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200803193127.3012242-2-robh@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kvm/arm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 691d21e4c717..46dc3d75cf13 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1640,6 +1640,10 @@ int kvm_arch_init(void *opaque) return -ENODEV; } + if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)) + kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \ + "Only trusted guests should be used on this system.\n"); + for_each_online_cpu(cpu) { smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1); if (ret < 0) { -- 2.34.1