[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3] x86/hvm: Allow guest_request vm_events coming from userspace
On 03/08/17 16:29, Alexandru Isaila wrote: > Allow guest userspace code to request that a vm_event be sent out > via VMCALL. This functionality seems to be handy for a number of > Xen developers, as stated on the mailing list (thread "[Xen-devel] > HVMOP_guest_request_vm_event only works from guest in ring0"). > This is a use case in communication between a userspace application > in the guest and the introspection application in dom0. This ends up as the immutable description of the change in history, once committed. May I recommend: "In some introspection usecases, an in-guest agent needs to communicate with the external introspection agent. An existing mechanism is HVMOP_guest_request_vm_event, but this is restricted to kernel usecases like all other hypercalls. Introduce a mechanism whereby the introspection agent can whitelist the use of HVMOP_guest_request_vm_event directly from userspace." ? > > Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx> > > --- > Changes since V2: > -Added a new flag to enable the vm call from the guest > userspace > --- > tools/libxc/include/xenctrl.h | 2 ++ > tools/libxc/xc_monitor.c | 14 ++++++++++++++ > xen/arch/x86/hvm/hypercall.c | 8 ++++++++ > xen/common/monitor.c | 13 +++++++++++++ > xen/include/public/domctl.h | 21 +++++++++++---------- > xen/include/xen/sched.h | 5 +++-- > 6 files changed, 51 insertions(+), 12 deletions(-) > > diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h > index bde8313..eed60db 100644 > --- a/tools/libxc/include/xenctrl.h > +++ b/tools/libxc/include/xenctrl.h > @@ -2022,6 +2022,8 @@ int xc_monitor_descriptor_access(xc_interface *xch, > domid_t domain_id, > bool enable); > int xc_monitor_guest_request(xc_interface *xch, domid_t domain_id, > bool enable, bool sync); > +int xc_monitor_guest_userspace_vmcall(xc_interface *xch, domid_t domain_id, > + bool enable); > int xc_monitor_debug_exceptions(xc_interface *xch, domid_t domain_id, > bool enable, bool sync); > int xc_monitor_cpuid(xc_interface *xch, domid_t domain_id, bool enable); > diff --git a/tools/libxc/xc_monitor.c b/tools/libxc/xc_monitor.c > index b44ce93..63c6320 100644 > --- a/tools/libxc/xc_monitor.c > +++ b/tools/libxc/xc_monitor.c > @@ -161,6 +161,20 @@ int xc_monitor_guest_request(xc_interface *xch, domid_t > domain_id, bool enable, > return do_domctl(xch, &domctl); > } > > +int xc_allow_guest_userspace_vmcall(xc_interface *xch, domid_t domain_id, > bool enable) > +{ > + DECLARE_DOMCTL; > + > + domctl.cmd = XEN_DOMCTL_monitor_op; > + domctl.domain = domain_id; > + domctl.u.monitor_op.op = enable ? XEN_DOMCTL_MONITOR_OP_ENABLE > + : XEN_DOMCTL_MONITOR_OP_DISABLE; > + domctl.u.monitor_op.event = > XEN_DOMCTL_MONITOR_EVENT_GUEST_USERSPACE_VMCALL; > + > + return do_domctl(xch, &domctl); > +} > + > + > int xc_monitor_emulate_each_rep(xc_interface *xch, domid_t domain_id, > bool enable) > { > diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c > index e7238ce..c7fab4b 100644 > --- a/xen/arch/x86/hvm/hypercall.c > +++ b/xen/arch/x86/hvm/hypercall.c > @@ -152,9 +152,17 @@ int hvm_hypercall(struct cpu_user_regs *regs) > { > case 8: > eax = regs->rax; > + if ( currd->monitor.guest_request_userspace_vmcall && > + eax == __HYPERVISOR_hvm_op && > + regs->rdi == HVMOP_guest_request_vm_event ) > + break; Newline > /* Fallthrough to permission check. */ > case 4: > case 2: > + if ( mode != 8 && currd->monitor.guest_request_userspace_vmcall && > + eax == __HYPERVISOR_hvm_op && > + regs->ebx == HVMOP_guest_request_vm_event ) > + break; Newline > if ( unlikely(hvm_get_cpl(curr)) ) > { > default: > diff --git a/xen/common/monitor.c b/xen/common/monitor.c > index 451f42f..4011dc3 100644 > --- a/xen/common/monitor.c > +++ b/xen/common/monitor.c > @@ -78,6 +78,19 @@ int monitor_domctl(struct domain *d, struct > xen_domctl_monitor_op *mop) > domain_unpause(d); > break; > } Newline > + case XEN_DOMCTL_MONITOR_EVENT_GUEST_USERSPACE_VMCALL: > + { > + bool_t old_status = d->monitor.guest_request_enabled; and bool here. All can be fixed on commit, if there are no other comments/concerns. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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