Re: [PATCH v2] KVM: x86: Always set kvm_run->if_flag

From: Paolo Bonzini
Date: Thu Dec 09 2021 - 12:50:03 EST


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@xxxxxxxxxx>

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).

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.

Paolo