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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5] x86/mm: Suppresses vm_events caused by page-walks
This patch is adding a way to enable/disable inguest pagefault
events. It introduces the xc_monitor_inguest_pagefault function
and adds the inguest_pagefault_disabled in the monitor structure.
This is needed by the introspection so it will only get gla
faults and not get spammed with other faults.
In p2m_mem_access_check() we emulate so no event will get sent.
Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
---
Changes since V4:
- Added the hvm_emulate_one_vm_event() call in
p2m_mem_access_check()
- Removed p2m_set_ad_bits().
---
tools/libxc/include/xenctrl.h | 2 ++
tools/libxc/xc_monitor.c | 14 ++++++++++++++
xen/arch/x86/mm/mem_access.c | 9 +++++++++
xen/arch/x86/monitor.c | 13 +++++++++++++
xen/include/asm-x86/domain.h | 5 +++++
xen/include/asm-x86/monitor.h | 3 ++-
xen/include/public/domctl.h | 2 ++
7 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 09e1363..20c2813 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2056,6 +2056,8 @@ int xc_monitor_descriptor_access(xc_interface *xch,
uint32_t domain_id,
bool enable);
int xc_monitor_guest_request(xc_interface *xch, uint32_t domain_id,
bool enable, bool sync, bool allow_userspace);
+int xc_monitor_inguest_pagefault(xc_interface *xch, uint32_t domain_id,
+ bool disable);
int xc_monitor_debug_exceptions(xc_interface *xch, uint32_t domain_id,
bool enable, bool sync);
int xc_monitor_cpuid(xc_interface *xch, uint32_t domain_id, bool enable);
diff --git a/tools/libxc/xc_monitor.c b/tools/libxc/xc_monitor.c
index 0233b87..4ac823e 100644
--- a/tools/libxc/xc_monitor.c
+++ b/tools/libxc/xc_monitor.c
@@ -163,6 +163,20 @@ int xc_monitor_guest_request(xc_interface *xch, uint32_t
domain_id, bool enable,
return do_domctl(xch, &domctl);
}
+int xc_monitor_inguest_pagefault(xc_interface *xch, uint32_t domain_id,
+ bool disable)
+{
+ DECLARE_DOMCTL;
+
+ domctl.cmd = XEN_DOMCTL_monitor_op;
+ domctl.domain = domain_id;
+ domctl.u.monitor_op.op = disable ? XEN_DOMCTL_MONITOR_OP_ENABLE
+ : XEN_DOMCTL_MONITOR_OP_DISABLE;
+ domctl.u.monitor_op.event = XEN_DOMCTL_MONITOR_EVENT_INGUEST_PAGEFAULT;
+
+ return do_domctl(xch, &domctl);
+}
+
int xc_monitor_emulate_each_rep(xc_interface *xch, uint32_t domain_id,
bool enable)
{
diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
index c0cd017..febe38d 100644
--- a/xen/arch/x86/mm/mem_access.c
+++ b/xen/arch/x86/mm/mem_access.c
@@ -28,6 +28,7 @@
#include <public/vm_event.h>
#include <asm/p2m.h>
#include <asm/altp2m.h>
+#include <asm/hvm/emulate.h>
#include <asm/vm_event.h>
#include "mm-locks.h"
@@ -207,6 +208,14 @@ bool p2m_mem_access_check(paddr_t gpa, unsigned long gla,
return true;
}
}
+ if ( vm_event_check_ring(d->vm_event_monitor) &&
+ d->arch.monitor.inguest_pagefault_disabled &&
+ npfec.kind != npfec_kind_with_gla ) /* don't send a mem_event */
+ {
+ hvm_emulate_one_vm_event(EMUL_KIND_NORMAL, TRAP_invalid_op,
X86_EVENT_NO_EC);
+
+ return true;
+ }
*req_ptr = NULL;
req = xzalloc(vm_event_request_t);
diff --git a/xen/arch/x86/monitor.c b/xen/arch/x86/monitor.c
index f229e69..ce5d1ba 100644
--- a/xen/arch/x86/monitor.c
+++ b/xen/arch/x86/monitor.c
@@ -241,6 +241,19 @@ int arch_monitor_domctl_event(struct domain *d,
break;
}
+ case XEN_DOMCTL_MONITOR_EVENT_INGUEST_PAGEFAULT:
+ {
+ bool old_status = ad->monitor.inguest_pagefault_disabled;
+
+ if ( unlikely(old_status == requested_status) )
+ return -EEXIST;
+
+ domain_pause(d);
+ ad->monitor.inguest_pagefault_disabled = requested_status;
+ domain_unpause(d);
+ break;
+ }
+
case XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS:
{
bool old_status = ad->monitor.descriptor_access_enabled;
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 4679d54..fbdc392 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -412,6 +412,11 @@ struct arch_domain
unsigned int descriptor_access_enabled : 1;
unsigned int guest_request_userspace_enabled : 1;
unsigned int emul_unimplemented_enabled : 1;
+ /*
+ * By default all events are sent.
+ * This is used to filter out pagefaults.
+ */
+ unsigned int inguest_pagefault_disabled : 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 a0444d1..647df4a 100644
--- a/xen/include/asm-x86/monitor.h
+++ b/xen/include/asm-x86/monitor.h
@@ -84,7 +84,8 @@ static inline uint32_t arch_monitor_get_capabilities(struct
domain *d)
(1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
(1U << XEN_DOMCTL_MONITOR_EVENT_CPUID) |
(1U << XEN_DOMCTL_MONITOR_EVENT_INTERRUPT) |
- (1U << XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED);
+ (1U << XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED) |
+ (1U << XEN_DOMCTL_MONITOR_EVENT_INGUEST_PAGEFAULT);
/* Since we know this is on VMX, we can just call the hvm func */
if ( hvm_is_singlestep_supported() )
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 9ae72959..ab89f35 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1014,6 +1014,8 @@ struct xen_domctl_psr_cmt_op {
#define XEN_DOMCTL_MONITOR_EVENT_INTERRUPT 8
#define XEN_DOMCTL_MONITOR_EVENT_DESC_ACCESS 9
#define XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED 10
+/* Enabled by default */
+#define XEN_DOMCTL_MONITOR_EVENT_INGUEST_PAGEFAULT 11
struct xen_domctl_monitor_op {
uint32_t op; /* XEN_DOMCTL_MONITOR_OP_* */
--
2.7.4
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