On Mon, Jun 26, 2017 at 01:09:58PM +0000, Paul Durrant wrote: > > -----Original Message----- > > From: Xen-devel [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of > > Marek Marczykowski-Górecki > > Sent: 26 June 2017 13:45 > > To: Juergen Groß <jgross@xxxxxxxx> > > Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; x86@xxxxxxxxxx; linux- > > kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx; xen- > > devel@xxxxxxxxxxxxxxxxxxxx; Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > > Subject: Re: [Xen-devel] [PATCH] x86/xen: allow userspace access during > > hypercalls > > > > On Mon, Jun 26, 2017 at 02:05:48PM +0200, Juergen Groß wrote: > > > On 06/23/2017 02:47 PM, Marek Marczykowski-Górecki wrote: > > > > Userspace application can do a hypercall through /dev/xen/privcmd, and > > > > some for some hypercalls argument is a pointers to user-provided > > > > structure. When SMAP is supported and enabled, hypervisor can't access. > > > > So, lets allow it. > > > > > > What about HYPERVISOR_dm_op? > > > > Indeed, arguments copied to kernel space there are only addresses of > > buffers. Will send v2 in a moment. > > But I can't test it right now, as for my understanding this require > > HVM/PVHv2 dom0 or stubdomain... > > > > No, you don't need anything particularly special to use dm_op. Just up-to-date xen, privcmd, and QEMU. QEMU should end up using dm_op by default if all three are in place. But the issue this patch fixes applies only to hypercalls issued from HVM. -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?
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