Messages in this thread | | | Subject | Re: [RESEND v4 1/2] KVM: VMX: Convert vcpu_vmx.exit_reason to a union | From | Chenyi Qiang <> | Date | Mon, 26 Oct 2020 13:31:06 +0800 |
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On 10/21/2020 6:01 AM, Sean Christopherson wrote: > On Mon, Oct 12, 2020 at 11:35:41AM +0800, Chenyi Qiang wrote: >> From: Sean Christopherson <sean.j.christopherson@intel.com> >> >> 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@intel.com> >> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > > This needs your SOB since you are involved in the handling of the patch. Sorry for the late response, my mailbox encountered some issues...
Will add the SOB here.
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