From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 0/3] Infinite loops in microcode while running guests Date: Tue, 10 Nov 2015 16:38:01 +0100 Message-ID: <56420F59.7080506@siemens.com> References: <1447158174-10484-1-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Cc: digitaleric@google.com To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: In-Reply-To: <1447158174-10484-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2015-11-10 13:22, Paolo Bonzini wrote: > Yes, these can happen. The issue is that benign exceptions are > delivered serially, but two of them (#DB and #AC) can also happen > during exception delivery itself. The subsequent infinite stream > of exceptions causes the processor to never exit guest mode. > > Paolo > > Eric Northup (1): > KVM: x86: work around infinite loop in microcode when #AC is delivered > > Paolo Bonzini (2): > KVM: svm: unconditionally intercept #DB > KVM: x86: rename update_db_bp_intercept to update_bp_intercept > > arch/x86/include/asm/kvm_host.h | 2 +- > arch/x86/include/uapi/asm/svm.h | 1 + > arch/x86/kvm/svm.c | 22 +++++++++++----------- > arch/x86/kvm/vmx.c | 7 +++++-- > arch/x86/kvm/x86.c | 2 +- > 5 files changed, 19 insertions(+), 15 deletions(-) > So this affects both Intel and AMD CPUs equally? Nice cross-vendor "compatibility". And it can only be triggered via #AC and #DB, or also other exceptions (that KVM already happens to intercept)? You may guess why I'm asking... Is any of the issues already documented in a vendor errata? Thanks, Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux