> -----Original Message----- > From: Sean Christopherson <seanjc@xxxxxxxxxx> > Sent: Wednesday, July 20, 2022 10:06 AM > To: Kechen Lu <kechenl@xxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx; pbonzini@xxxxxxxxxx; chao.gao@xxxxxxxxx; > vkuznets@xxxxxxxxxx; Somdutta Roy <somduttar@xxxxxxxxxx>; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [RFC PATCH v4 6/7] KVM: x86: Add a new guest_debug flag > forcing exit to userspace > > External email: Use caution opening links or attachments > > > On Tue, Jun 21, 2022, Kechen Lu wrote: > > For debug and test purposes, there are needs to explicitly make > > instruction triggered exits could be trapped to userspace. Simply add > > a new flag for guest_debug interface could achieve this. > > > > This patch also fills the userspace accessible field > > vcpu->run->hw.hardware_exit_reason for userspace to determine the > > original triggered VM-exits. > > This patch belongs in a different series, AFAICT there are no dependencies > between this and allowing per-vCPU disabling of exits. Allowing userspace to > exit on "every" instruction exit is going to be much more controversial, > largely because it will be difficult for KVM to provide a consistent, robust ABI. > E.g. should KVM exit to userspace if an intercepted instruction is > encountered by the emualtor? > > TL;DR: drop this patch from the next version. Ack. This patch I introduced as prerequisite for the patch 7 of implementing the selftests for KVM_CAP_X86_DISABLE_EXITS. But yeah, it's not a good practice, I will try to think about a better way to implement the disabled exits testing. BR, Kechen
