On Thu, Feb 11, 2016 at 1:59 PM, Razvan Cojocaru <rcojoc...@bitdefender.com> wrote:
> On 02/11/2016 10:38 PM, Tamas K Lengyel wrote: > > > > > > On Thu, Feb 11, 2016 at 1:13 PM, Razvan Cojocaru > > <rcojoc...@bitdefender.com <mailto:rcojoc...@bitdefender.com>> wrote: > > > > On 02/11/2016 10:04 PM, Andrew Cooper wrote: > > > On 11/02/16 20:00, Razvan Cojocaru wrote: > > >> On 02/11/2016 09:55 PM, Andrew Cooper wrote: > > >>> On 11/02/16 19:54, Razvan Cojocaru wrote: > > >>>> On 02/11/2016 09:51 PM, Tamas K Lengyel wrote: > > >>>>> While the public vm_event header specifies fs_base/gs_base as > > registers that > > >>>>> should be recorded for each event, that hasn't actually been > > the case. In > > >>>>> this patch we remedy the issue. > > >>>>> > > >>>>> Signed-off-by: Tamas K Lengyel <tleng...@novetta.com > > <mailto:tleng...@novetta.com>> > > >>>>> Cc: Razvan Cojocaru <rcojoc...@bitdefender.com > > <mailto:rcojoc...@bitdefender.com>> > > >>>>> Cc: Keir Fraser <k...@xen.org <mailto:k...@xen.org>> > > >>>>> Cc: Jan Beulich <jbeul...@suse.com <mailto:jbeul...@suse.com>> > > >>>>> Cc: Andrew Cooper <andrew.coop...@citrix.com > > <mailto:andrew.coop...@citrix.com>> > > >>>>> --- > > >>>>> xen/arch/x86/hvm/event.c | 9 ++++++++- > > >>>>> 1 file changed, 8 insertions(+), 1 deletion(-) > > >>>> Fair enough. > > >>>> > > >>>> Acked-by: Razvan Cojocaru <rcojoc...@bitdefender.com > > <mailto:rcojoc...@bitdefender.com>> > > >>> Oops. > > >>> > > >>> Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com > > <mailto:andrew.coop...@citrix.com>> > > >> This has actually been intentional, in that we've only needed > those > > >> fields for EPT events, and thought that not filling what's not > needed > > >> until it's needed would save a tiny bit of hypervisor processing > > time. > > >> They are being filled in only for page fault events at the moment. > > >> > > >> I believe it's been discussed at the time. We still don't need > those > > >> coming with the events that use hvm_event_fill_regs(), but if > Tamas > > >> needs them then by all means. > > > > > > The public header file does suggest that all of vm_event_regs_x86 > will > > > be complete. Are there any other fields currently missing? > > > > There are. p2m_vm_event_fill_regs() fills everything in (in > > xen/arch/x86/mm/p2m.c). hvm_event_fill_regs() still does not, even > after > > Tamas' patch. > > > > > > Ah, that makes sense. Yea, I would prefer if all registers would get > > filled in for all events so I'll just consolidate these two functions > > into one. > > Right, but please be careful and test that you get correct values with > all events (page fault events + the others), I remember that for some > reason I needed to use different ways to get at the same values in > p2m_vm_event_fill_regs() and hvm_event_fill_regs(). > > For example, p2m_vm_event_fill_regs() does: > > hvm_funcs.save_cpu_ctxt(curr, &ctxt); > req->data.regs.x86.cr0 = ctxt.cr0; > > and hvm_event_fill_regs() does: > > req->data.regs.x86.cr0 = curr->arch.hvm_vcpu.guest_cr[0]; > > I don't remember exactly why I had to do that at the time, but I do > recall it being necessary. > That sounds odd to me. As far as I can tell everything works just right with the other patch I just sent. I looked into what hvm_funcs.save_cpu_ctxt does on Intel and it calls vmx_save_vmcs_ctxt which calls vmx_vmcs_save. That has:
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