From: Alexandru Isaila Date: Wed, 30 Aug 2017 09:04:13 +0000 (+0200) Subject: x86/hvm: allow guest_request vm_events coming from userspace X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~1526 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=7c4dc5dbdfd383cd58bcac522f746409e9c0c267;p=xen.git x86/hvm: allow guest_request vm_events coming from userspace 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 Acked-by: Wei Liu Acked-by: Jan Beulich Acked-by: Tamas K Lengyel --- diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h index ad5e6b3d77..43151cb415 100644 --- a/tools/libxc/include/xenctrl.h +++ b/tools/libxc/include/xenctrl.h @@ -2022,7 +2022,7 @@ int xc_monitor_software_breakpoint(xc_interface *xch, domid_t domain_id, 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); + bool enable, bool sync, bool allow_userspace); 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 b44ce93be7..a67782009d 100644 --- a/tools/libxc/xc_monitor.c +++ b/tools/libxc/xc_monitor.c @@ -147,7 +147,7 @@ int xc_monitor_descriptor_access(xc_interface *xch, domid_t domain_id, } int xc_monitor_guest_request(xc_interface *xch, domid_t domain_id, bool enable, - bool sync) + bool sync, bool allow_userspace) { DECLARE_DOMCTL; @@ -157,6 +157,7 @@ int xc_monitor_guest_request(xc_interface *xch, domid_t domain_id, bool enable, : XEN_DOMCTL_MONITOR_OP_DISABLE; domctl.u.monitor_op.event = XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST; domctl.u.monitor_op.u.guest_request.sync = sync; + domctl.u.monitor_op.u.guest_request.allow_userspace = enable ? allow_userspace : false; return do_domctl(xch, &domctl); } diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c index e7238ce293..5742dd1797 100644 --- a/xen/arch/x86/hvm/hypercall.c +++ b/xen/arch/x86/hvm/hypercall.c @@ -155,6 +155,11 @@ int hvm_hypercall(struct cpu_user_regs *regs) /* Fallthrough to permission check. */ case 4: case 2: + if ( currd->arch.monitor.guest_request_userspace_enabled && + eax == __HYPERVISOR_hvm_op && + (mode == 8 ? regs->rdi : 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 451f42f6c3..4c540e5665 100644 --- a/xen/common/monitor.c +++ b/xen/common/monitor.c @@ -75,6 +75,7 @@ int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *mop) domain_pause(d); d->monitor.guest_request_sync = mop->u.guest_request.sync; d->monitor.guest_request_enabled = requested_status; + arch_monitor_allow_userspace(d, mop->u.guest_request.allow_userspace); domain_unpause(d); break; } diff --git a/xen/include/asm-arm/monitor.h b/xen/include/asm-arm/monitor.h index 1c4fea395f..7567be66bd 100644 --- a/xen/include/asm-arm/monitor.h +++ b/xen/include/asm-arm/monitor.h @@ -25,6 +25,11 @@ #include #include +static inline +void arch_monitor_allow_userspace(struct domain *d, bool allow_userspace) +{ +} + static inline int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op *mop) { diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h index c10522b7f5..de0250725a 100644 --- a/xen/include/asm-x86/domain.h +++ b/xen/include/asm-x86/domain.h @@ -396,15 +396,16 @@ struct arch_domain /* Arch-specific monitor options */ struct { - unsigned int write_ctrlreg_enabled : 4; - unsigned int write_ctrlreg_sync : 4; - unsigned int write_ctrlreg_onchangeonly : 4; - unsigned int singlestep_enabled : 1; - unsigned int software_breakpoint_enabled : 1; - unsigned int debug_exception_enabled : 1; - unsigned int debug_exception_sync : 1; - unsigned int cpuid_enabled : 1; - unsigned int descriptor_access_enabled : 1; + unsigned int write_ctrlreg_enabled : 4; + unsigned int write_ctrlreg_sync : 4; + unsigned int write_ctrlreg_onchangeonly : 4; + unsigned int singlestep_enabled : 1; + unsigned int software_breakpoint_enabled : 1; + unsigned int debug_exception_enabled : 1; + unsigned int debug_exception_sync : 1; + unsigned int cpuid_enabled : 1; + unsigned int descriptor_access_enabled : 1; + unsigned int guest_request_userspace_enabled : 1; struct monitor_msr_bitmap *msr_bitmap; uint64_t write_ctrlreg_mask[4]; } monitor; diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h index c5c323b6aa..765d0b41d2 100644 --- a/xen/include/asm-x86/monitor.h +++ b/xen/include/asm-x86/monitor.h @@ -32,6 +32,12 @@ struct monitor_msr_bitmap { DECLARE_BITMAP(high, 8192); }; +static inline +void arch_monitor_allow_userspace(struct domain *d, bool allow_userspace) +{ + d->arch.monitor.guest_request_userspace_enabled = allow_userspace; +} + static inline int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op *mop) { diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h index 73d8dc85f7..83c7c75835 100644 --- a/xen/include/public/domctl.h +++ b/xen/include/public/domctl.h @@ -1128,6 +1128,7 @@ struct xen_domctl_monitor_op { struct { /* Pause vCPU until response */ uint8_t sync; + uint8_t allow_userspace; } guest_request; struct {