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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3] x86/hvm: Allow guest_request vm_events coming from userspace
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.
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;
/* 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;
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;
}
+ case XEN_DOMCTL_MONITOR_EVENT_GUEST_USERSPACE_VMCALL:
+ {
+ bool_t old_status = d->monitor.guest_request_enabled;
+
+ if ( unlikely(old_status == requested_status) )
+ return -EEXIST;
+
+ domain_pause(d);
+ d->monitor.guest_request_sync = mop->u.guest_request.sync;
+ d->monitor.guest_request_userspace_vmcall = requested_status;
+ domain_unpause(d);
+ break;
+ }
default:
/* Give arch-side the chance to handle this event */
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index ff39762..e782517 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1073,16 +1073,17 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_psr_cmt_op_t);
#define XEN_DOMCTL_MONITOR_OP_GET_CAPABILITIES 2
#define XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP 3
-#define XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG 0
-#define XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR 1
-#define XEN_DOMCTL_MONITOR_EVENT_SINGLESTEP 2
-#define XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT 3
-#define XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST 4
-#define XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION 5
-#define XEN_DOMCTL_MONITOR_EVENT_CPUID 6
-#define XEN_DOMCTL_MONITOR_EVENT_PRIVILEGED_CALL 7
-#define XEN_DOMCTL_MONITOR_EVENT_INTERRUPT 8
-#define XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS 9
+#define XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG 0
+#define XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR 1
+#define XEN_DOMCTL_MONITOR_EVENT_SINGLESTEP 2
+#define XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT 3
+#define XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST 4
+#define XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION 5
+#define XEN_DOMCTL_MONITOR_EVENT_CPUID 6
+#define XEN_DOMCTL_MONITOR_EVENT_PRIVILEGED_CALL 7
+#define XEN_DOMCTL_MONITOR_EVENT_INTERRUPT 8
+#define XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS 9
+#define XEN_DOMCTL_MONITOR_EVENT_GUEST_USERSPACE_VMCALL 10
struct xen_domctl_monitor_op {
uint32_t op; /* XEN_DOMCTL_MONITOR_OP_* */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 6673b27..11137b0 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -480,8 +480,9 @@ struct domain
/* Common monitor options */
struct {
- unsigned int guest_request_enabled : 1;
- unsigned int guest_request_sync : 1;
+ unsigned int guest_request_enabled : 1;
+ unsigned int guest_request_sync : 1;
+ unsigned int guest_request_userspace_vmcall : 1;
} monitor;
};
--
2.7.4
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