On Mon, Oct 12, 2020 at 11:35:41AM +0800, Chenyi Qiang wrote: > From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > Convert vcpu_vmx.exit_reason from a u32 to a union (of size u32). The > full VM_EXIT_REASON field is comprised of a 16-bit basic exit reason in > bits 15:0, and single-bit modifiers in bits 31:16. > > Historically, KVM has only had to worry about handling the "failed > VM-Entry" modifier, which could only be set in very specific flows and > required dedicated handling. I.e. manually stripping the FAILED_VMENTRY > bit was a somewhat viable approach. But even with only a single bit to > worry about, KVM has had several bugs related to comparing a basic exit > reason against the full exit reason store in vcpu_vmx. > > Upcoming Intel features, e.g. SGX, will add new modifier bits that can > be set on more or less any VM-Exit, as opposed to the significantly more > restricted FAILED_VMENTRY, i.e. correctly handling everything in one-off > flows isn't scalable. Tracking exit reason in a union forces code to > explicitly choose between consuming the full exit reason and the basic > exit, and is a convenient way to document and access the modifiers. > > No functional change intended. > > Cc: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> This needs your SOB since you are involved in the handling of the patch.
