Messages in this thread | | | From | Jim Mattson <> | Date | Thu, 9 Dec 2021 10:20:22 -0800 | Subject | Re: [PATCH v2] KVM: x86: Always set kvm_run->if_flag |
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On Thu, Dec 9, 2021 at 9:48 AM Paolo Bonzini <pbonzini@redhat.com> wrote: > > On 12/9/21 16:52, Marc Orr wrote: > > The kvm_run struct's if_flag is a part of the userspace/kernel API. The > > SEV-ES patches failed to set this flag because it's no longer needed by > > QEMU (according to the comment in the source code). However, other > > hypervisors may make use of this flag. Therefore, set the flag for > > guests with encrypted registers (i.e., with guest_state_protected set). > > > > Fixes: f1c6366e3043 ("KVM: SVM: Add required changes to support intercepts under SEV-ES") > > Signed-off-by: Marc Orr<marcorr@google.com> > > Applied, though I wonder if it is really needed by those other VMMs > (which? gVisor is the only one that comes to mind that is interested in > userspace APIC).
Vanadium appears to have one use of it.
> It shouldn't be necessary for in-kernel APIC (where userspace can inject > interrupts at any time), and ready_for_interrupt_injection is superior > for userspace APIC.
LOL. Here's that one use...
if (vcpu_run_state_->request_interrupt_window && vcpu_run_state_->ready_for_interrupt_injection && vcpu_run_state_->if_flag) { ... }
So, maybe this is much ado about nothing?
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