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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200923224530.17735-1-sean.j.christopherson@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-24_02:2020-09-24,2020-09-24 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxlogscore=809 mlxscore=0 adultscore=0 priorityscore=1501 malwarescore=0 spamscore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 clxscore=1015 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009240049 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 24.09.20 00:45, Sean Christopherson wrote: > This series introduces a concept we've discussed a few times in x86 land. > The crux of the problem is that x86 has a few cases where KVM could > theoretically encounter a software or hardware bug deep in a call stack > without any sane way to propagate the error out to userspace. > > Another use case would be for scenarios where letting the VM live will > do more harm than good, e.g. we've been using KVM_BUG_ON for early TDX > enabling as botching anything related to secure paging all but guarantees > there will be a flood of WARNs and error messages because lower level PTE > operations will fail if an upper level operation failed. > > The basic idea is to WARN_ONCE if a bug is encountered, kick all vCPUs out > to userspace, and mark the VM as bugged so that no ioctls() can be issued > on the VM or its devices/vCPUs. > > RFC as I've done nowhere near enough testing to verify that rejecting the > ioctls(), evicting running vCPUs, etc... works as intended. I like the idea. Especially when we add a common "understanding" in QEMU across all platforms. That would then even allow to propagate an error. > > Sean Christopherson (3): > KVM: Export kvm_make_all_cpus_request() for use in marking VMs as > bugged > KVM: Add infrastructure and macro to mark VM as bugged > KVM: x86: Use KVM_BUG/KVM_BUG_ON to handle bugs that are fatal to the > VM > > arch/x86/kvm/svm/svm.c | 2 +- > arch/x86/kvm/vmx/vmx.c | 23 ++++++++++++-------- > arch/x86/kvm/x86.c | 4 ++++ > include/linux/kvm_host.h | 45 ++++++++++++++++++++++++++++++++-------- > virt/kvm/kvm_main.c | 11 +++++----- > 5 files changed, 61 insertions(+), 24 deletions(-) >