Re: [PATCH v3 2/2] kvm: x86: hyperv: guest->host event signaling via eventfd

[Roman Kagan <rkagan@virtuozzo.com>]

On Tue, Dec 12, 2017 at 01:17:23PM +0300, Roman Kagan wrote:
> On Tue, Dec 12, 2017 at 10:37:31AM +0100, David Hildenbrand wrote:
> > On 12.12.2017 10:02, Roman Kagan wrote:
> > > On Mon, Dec 11, 2017 at 10:14:48PM +0100, David Hildenbrand wrote:
> > >>> @@ -1226,6 +1227,54 @@ static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
> > >>>  	return 1;
> > >>>  }
> > >>>  
> > >>> +static u16 hvcall_sigevent_param(struct kvm_vcpu *vcpu, gpa_t gpa, u64 *param)
> > >>> +{
> > >>> +	struct page *page;
> > >>> +	void *pg;
> > >>> +	u64 *msg;
> > >>> +
> > >>> +	if ((gpa & (__alignof__(*msg) - 1)) ||
> > >>> +	    offset_in_page(gpa) + sizeof(*msg) > PAGE_SIZE)
> > >>> +		return HV_STATUS_INVALID_ALIGNMENT;
> > >>> +
> > >>
> > >> Don't we also need srcu_read_lock(&vcpu->kvm->srcu) for
> > >> kvm_vcpu_gfn_to_page?
> > > 
> > > Seems so indeed.  I also think I'll switch to using
> > > kvm_vcpu_read_guest().
> > 
> > Probably better (because I think you also missed releasing the page)
> 
> Hmm, I wonder where?  (kvm_vcpu_read_guest ended up being more concise
> so I'll stick with it but I'd like to learn from my errors anyway.)

Nevermind, I screwed up my branches.  The one I posted was missing
kvm_release_page_clean() indeed.

Thanks,
Roman.