On Tue, 2010-04-27 at 15:47 +0800, Avi Kivity wrote:
> (please copy [email protected] on kvm patches)
Sorry, will do that for all future patches.
> On 04/27/2010 10:04 AM, Huang Ying wrote:
> >
> > +static void kvm_send_hwpoison_signal(struct kvm *kvm, gfn_t gfn)
> > +{
> > + char buf[1];
> > + void __user *hva;
> > + int r;
> > +
> > + /* Touch the page, so send SIGBUS */
> > + hva = (void __user *)gfn_to_hva(kvm, gfn);
> > + r = copy_from_user(buf, hva, 1);
> >
>
> No error check? What will a copy_from_user() of poisoned page expected
> to return?
>
> Best to return -EFAULT on failure for consistency.
Just want to use the side effect of copy_from_user, SIGBUS will be sent
to current process because the page touched is marked as poisoned. That
is, failure is expected, so the return value is not checked.
> > +}
> > +
> > static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t
> > gfn)
> > {
> > int r;
> > @@ -1997,7 +2009,11 @@ static int nonpaging_map(struct kvm_vcpu
> > /* mmio */
> > if (is_error_pfn(pfn)) {
> > kvm_release_pfn_clean(pfn);
> > - return 1;
> > + if (is_hwpoison_pfn(pfn)) {
> > + kvm_send_hwpoison_signal(vcpu->kvm, gfn);
> > + return 0;
> > + } else
> > + return 1;
> > }
> >
>
> This is duplicated several times. Please introduce a kvm_handle_bad_page():
>
> if (is_error_pfn(pfn))
> return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
OK. Will do that.
Best Regards,
Huang Ying
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