On Fri, Oct 07, 2022 at 01:39:17AM +0000, Sean Christopherson wrote:
> On Tue, Aug 16, 2022, Peter Xu wrote:
> > Since at it, renaming kvm_handle_bad_page to kvm_handle_error_pfn assuming
>
> Please put parantheses after function names, e.g. kvm_handle_bad_page().
>
> > that'll match better with what it does, e.g. KVM_PFN_ERR_SIGPENDING is not
> > accurately a bad page but just one kind of errors.
>
> ...
>
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index 3e1317325e1f..23dc46da2f18 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -3134,8 +3134,13 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *
> > send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk);
> > }
> >
> > -static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
> > +static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
> > {
> > + if (is_sigpending_pfn(pfn)) {
> > + kvm_handle_signal_exit(vcpu);
> > + return -EINTR;
> > + }
>
> ...
>
> > @@ -2648,9 +2651,12 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
> > if (atomic)
> > return KVM_PFN_ERR_FAULT;
> >
> > - npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
> > + npages = hva_to_pfn_slow(addr, async, write_fault, interruptible,
> > + writable, &pfn);
> > if (npages == 1)
> > return pfn;
> > + if (npages == -EINTR)
> > + return KVM_PFN_ERR_SIGPENDING;
>
> This patch should be split into 3 parts:
>
> 1. Add KVM_PFN_ERR_SIGPENDING and the above code
> 2. Add the interruptible flag
> 3. Add handling in x86 and rename kvm_handle_bad_page()
>
> With #3 merged with patch 3.
>
> That was if there's oddball arch code that reacts poorly to KVM_PFN_ERR_SIGPENDING,
> those errors will bisect to #1.
>
> And if there's a typo in the plumbing, that bisects to #2.
>
> And if something goes sideways in x86, those bugs bisect to #3 (patch 3), and it's
> easy to revert just the x86 changes (though I can't imagine that's likely).
Yeah the x86 change in this patch is indeed a bit weird with the generic
subject. All points taken, thanks.
--
Peter Xu
