On 30/03/2018 00:41, Sean Christopherson wrote:
> Redo kvm_mmu_page_fault()'s interaction with handle_mmio_page_fault()
> so that the behavior of falling through to mmu.page_fault() when
> handle_mmio_page_fault() returns RET_PF_INVALID is more obvious.
> The current approach of setting and checking RET_PF_INVALID outside
> of the MMIO flow can lead readers to believe that RET_PF_INVALID
> may be used for something other than signifying that the MMIO generation
> has changed.
>
> This is a purely cosmetic change, e.g. kvm.ko's kvm_mmu_page_fault
> is binary identical on my system before and after this patch
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index f551962ac294..662bb448c7fc 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -4927,21 +4927,21 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
> vcpu->arch.gpa_val = cr2;
> }
>
> - r = RET_PF_INVALID;
> if (unlikely(error_code & PFERR_RSVD_MASK)) {
> r = handle_mmio_page_fault(vcpu, cr2, direct);
> if (r == RET_PF_EMULATE) {
> emulation_type = 0;
> goto emulate;
> }
> + if (r != RET_PF_INVALID)
> + goto pf_done;
> }
>
> - if (r == RET_PF_INVALID) {
> - r = vcpu->arch.mmu.page_fault(vcpu, cr2, lower_32_bits(error_code),
> - false);
> - WARN_ON(r == RET_PF_INVALID);
> - }
> + r = vcpu->arch.mmu.page_fault(vcpu, cr2, lower_32_bits(error_code),
> + false);
> + WARN_ON(r == RET_PF_INVALID);
>
> +pf_done:
> if (r == RET_PF_RETRY)
> return 1;
> if (r < 0)
>
I don't know... The extra goto makes things a bit harder to read. Maybe
moving the "emulate" label to a separate function can make things more
bearable, but I'm not sure about that either. For now I'm not applying
the patch.
Paolo
