> -----Original Message----- > From: 'Marek Marczykowski-Górecki' > [mailto:marma...@invisiblethingslab.com] > Sent: 26 June 2017 14:22 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: Juergen Groß <jgr...@suse.com>; Andrew Cooper > <andrew.coop...@citrix.com>; x...@kernel.org; linux- > ker...@vger.kernel.org; sta...@vger.kernel.org; xen- > de...@lists.xenproject.org; Boris Ostrovsky <boris.ostrov...@oracle.com> > Subject: Re: [Xen-devel] [PATCH] x86/xen: allow userspace access during > hypercalls > > On Mon, Jun 26, 2017 at 01:09:58PM +0000, Paul Durrant wrote: > > > -----Original Message----- > > > From: Xen-devel [mailto:xen-devel-boun...@lists.xen.org] On Behalf Of > > > Marek Marczykowski-Górecki > > > Sent: 26 June 2017 13:45 > > > To: Juergen Groß <jgr...@suse.com> > > > Cc: Andrew Cooper <andrew.coop...@citrix.com>; x...@kernel.org; > linux- > > > ker...@vger.kernel.org; sta...@vger.kernel.org; xen- > > > de...@lists.xenproject.org; Boris Ostrovsky > <boris.ostrov...@oracle.com> > > > 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.
Oh, I see what you mean. Well I guess you could manually run QEMU from an HVM domain, but it would be a bit of a faff to set up. Paul > > -- > 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?
