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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH RFC V6 3/5] xen, libxc: Force-enable relevant MSR events
Vmx_disable_intercept_for_msr() will now refuse to disable interception of
MSRs needed for memory introspection. It is not possible to gate this on
mem_access being active for the domain, since by the time mem_access does
become active the interception for the interesting MSRs has already been
disabled (vmx_disable_intercept_for_msr() runs very early on).
Changes since V1:
- Replaced printk() with gdprintk(XENLOG_DEBUG, ...).
Changes since V2:
- Split a log line differently to keep it grepable.
- Interception for relevant MSRs will be disabled only if
mem_access is not enabled.
- Since they end up being disabled early on (when mem_access
is not enabled yet), re-enable interception when mem_access
becomes active.
Changes since V3:
- Removed log line stating that MSR interception cannot be disabled.
- Removed superfluous #include <asm/hvm/vmx/vmcs.h>.
- Moved VMX-specific code to vmx.c (as a new hvm_funcs member).
Changes since V5:
- Added xc_mem_access_enable_introspection() to libxc, which has
the same parameters and semantics as xc_mem_access_enable(),
but it additionally sets d->arch.hvm_domain.introspection_enabled
and enables relevant MSR interception.
- Renamed vmx_enable_intro_msr_interception() to
vmx_enable_msr_exit_interception().
- Simplified vmx_enable_msr_exit_interception() (const array of MSRs).
Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
---
tools/libxc/xc_mem_access.c | 10 +++++++++-
tools/libxc/xc_mem_event.c | 7 +++++--
tools/libxc/xc_private.h | 2 +-
tools/libxc/xenctrl.h | 2 ++
xen/arch/x86/hvm/vmx/vmcs.c | 21 +++++++++++++++++++++
xen/arch/x86/hvm/vmx/vmx.c | 18 ++++++++++++++++++
xen/arch/x86/mm/mem_event.c | 13 +++++++++++++
xen/include/asm-x86/hvm/domain.h | 2 ++
xen/include/asm-x86/hvm/hvm.h | 2 ++
xen/include/public/domctl.h | 7 ++++---
10 files changed, 77 insertions(+), 7 deletions(-)
diff --git a/tools/libxc/xc_mem_access.c b/tools/libxc/xc_mem_access.c
index 461f0e9..55d0e9f 100644
--- a/tools/libxc/xc_mem_access.c
+++ b/tools/libxc/xc_mem_access.c
@@ -26,7 +26,15 @@
void *xc_mem_access_enable(xc_interface *xch, domid_t domain_id, uint32_t
*port)
{
- return xc_mem_event_enable(xch, domain_id, HVM_PARAM_ACCESS_RING_PFN,
port);
+ return xc_mem_event_enable(xch, domain_id, HVM_PARAM_ACCESS_RING_PFN,
+ port, 0);
+}
+
+void *xc_mem_access_enable_introspection(xc_interface *xch, domid_t domain_id,
+ uint32_t *port)
+{
+ return xc_mem_event_enable(xch, domain_id, HVM_PARAM_ACCESS_RING_PFN,
+ port, 1);
}
int xc_mem_access_disable(xc_interface *xch, domid_t domain_id)
diff --git a/tools/libxc/xc_mem_event.c b/tools/libxc/xc_mem_event.c
index faf1cc6..8c0be4e 100644
--- a/tools/libxc/xc_mem_event.c
+++ b/tools/libxc/xc_mem_event.c
@@ -57,7 +57,7 @@ int xc_mem_event_memop(xc_interface *xch, domid_t domain_id,
}
void *xc_mem_event_enable(xc_interface *xch, domid_t domain_id, int param,
- uint32_t *port)
+ uint32_t *port, int enable_introspection)
{
void *ring_page = NULL;
uint64_t pfn;
@@ -120,7 +120,10 @@ void *xc_mem_event_enable(xc_interface *xch, domid_t
domain_id, int param,
break;
case HVM_PARAM_ACCESS_RING_PFN:
- op = XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE;
+ if ( enable_introspection )
+ op = XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE_INTROSPECTION;
+ else
+ op = XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE;
mode = XEN_DOMCTL_MEM_EVENT_OP_ACCESS;
break;
diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
index c50a7c9..94df688 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -381,6 +381,6 @@ int xc_mem_event_memop(xc_interface *xch, domid_t domain_id,
* param can be HVM_PARAM_PAGING/ACCESS/SHARING_RING_PFN
*/
void *xc_mem_event_enable(xc_interface *xch, domid_t domain_id, int param,
- uint32_t *port);
+ uint32_t *port, int enable_introspection);
#endif /* __XC_PRIVATE_H__ */
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 5beb846..f7785ec 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -2263,6 +2263,8 @@ int xc_mem_paging_load(xc_interface *xch, domid_t
domain_id,
* Caller has to unmap this page when done.
*/
void *xc_mem_access_enable(xc_interface *xch, domid_t domain_id, uint32_t
*port);
+void *xc_mem_access_enable_introspection(xc_interface *xch, domid_t domain_id,
+ uint32_t *port);
int xc_mem_access_disable(xc_interface *xch, domid_t domain_id);
int xc_mem_access_resume(xc_interface *xch, domid_t domain_id);
diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 8ffc562..2ac2872 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -39,6 +39,7 @@
#include <xen/keyhandler.h>
#include <asm/shadow.h>
#include <asm/tboot.h>
+#include <asm/mem_event.h>
static bool_t __read_mostly opt_vpid_enabled = 1;
boolean_param("vpid", opt_vpid_enabled);
@@ -695,11 +696,31 @@ static void vmx_set_host_env(struct vcpu *v)
void vmx_disable_intercept_for_msr(struct vcpu *v, u32 msr, int type)
{
unsigned long *msr_bitmap = v->arch.hvm_vmx.msr_bitmap;
+ struct domain *d = v->domain;
/* VMX MSR bitmap supported? */
if ( msr_bitmap == NULL )
return;
+ if ( mem_event_check_ring(&d->mem_event->access) &&
+ d->arch.hvm_domain.introspection_enabled )
+ {
+ /* Filter out MSR-s needed for memory introspection */
+ switch ( msr )
+ {
+ case MSR_IA32_SYSENTER_EIP:
+ case MSR_IA32_SYSENTER_ESP:
+ case MSR_IA32_SYSENTER_CS:
+ case MSR_IA32_MC0_CTL:
+ case MSR_STAR:
+ case MSR_LSTAR:
+ return;
+
+ default:
+ break;
+ }
+ }
+
/*
* See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address). Early manuals
* have the write-low and read-high bitmap offsets the wrong way round.
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 2caa04a..4cab482 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1682,6 +1682,23 @@ void vmx_hypervisor_cpuid_leaf(uint32_t sub_idx,
*eax |= XEN_HVM_CPUID_X2APIC_VIRT;
}
+static void vmx_enable_msr_exit_interception(struct domain *d)
+{
+ struct vcpu *v;
+ const u32 msrs[] = { MSR_IA32_SYSENTER_EIP,
+ MSR_IA32_SYSENTER_ESP,
+ MSR_IA32_SYSENTER_CS,
+ MSR_IA32_MC0_CTL,
+ MSR_STAR,
+ MSR_LSTAR };
+ int i;
+
+ /* Enable interception for MSRs needed for memory introspection. */
+ for_each_vcpu ( d, v )
+ for ( i = 0; i < ARRAY_SIZE(msrs); i++ )
+ vmx_enable_intercept_for_msr(v, msrs[i], MSR_TYPE_W);
+}
+
static struct hvm_function_table __initdata vmx_function_table = {
.name = "VMX",
.cpu_up_prepare = vmx_cpu_up_prepare,
@@ -1740,6 +1757,7 @@ static struct hvm_function_table __initdata
vmx_function_table = {
.handle_eoi = vmx_handle_eoi,
.nhvm_hap_walk_L1_p2m = nvmx_hap_walk_L1_p2m,
.hypervisor_cpuid_leaf = vmx_hypervisor_cpuid_leaf,
+ .enable_msr_exit_interception = vmx_enable_msr_exit_interception,
};
const struct hvm_function_table * __init start_vmx(void)
diff --git a/xen/arch/x86/mm/mem_event.c b/xen/arch/x86/mm/mem_event.c
index ba7e71e..84a1d8d 100644
--- a/xen/arch/x86/mm/mem_event.c
+++ b/xen/arch/x86/mm/mem_event.c
@@ -587,6 +587,7 @@ int mem_event_domctl(struct domain *d,
xen_domctl_mem_event_op_t *mec,
switch( mec->op )
{
case XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE:
+ case XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE_INTROSPECTION:
{
rc = -ENODEV;
/* Only HAP is supported */
@@ -600,13 +601,25 @@ int mem_event_domctl(struct domain *d,
xen_domctl_mem_event_op_t *mec,
rc = mem_event_enable(d, mec, med, _VPF_mem_access,
HVM_PARAM_ACCESS_RING_PFN,
mem_access_notification);
+
+ if ( mec->op == XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE )
+ break;
+
+ if ( rc == 0 && hvm_funcs.enable_msr_exit_interception )
+ {
+ d->arch.hvm_domain.introspection_enabled = 1;
+ hvm_funcs.enable_msr_exit_interception(d);
+ }
}
break;
case XEN_DOMCTL_MEM_EVENT_OP_ACCESS_DISABLE:
{
if ( med->ring_page )
+ {
rc = mem_event_disable(d, med);
+ d->arch.hvm_domain.introspection_enabled = 0;
+ }
}
break;
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 291a2e0..947b061 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -145,6 +145,8 @@ struct hvm_domain {
struct vmx_domain vmx;
struct svm_domain svm;
};
+
+ bool_t introspection_enabled;
};
#define hap_enabled(d) ((d)->arch.hvm_domain.hap_enabled)
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 0ebd478..069ba39 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -205,6 +205,8 @@ struct hvm_function_table {
void (*hypervisor_cpuid_leaf)(uint32_t sub_idx,
uint32_t *eax, uint32_t *ebx,
uint32_t *ecx, uint32_t *edx);
+
+ void (*enable_msr_exit_interception)(struct domain *d);
};
extern struct hvm_function_table hvm_funcs;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 5b11bbf..a3431ec 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -772,10 +772,11 @@ struct xen_domctl_gdbsx_domstatus {
* ENODEV - host lacks HAP support (EPT/NPT) or HAP is disabled in guest
* EBUSY - guest has or had access enabled, ring buffer still active
*/
-#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS 2
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS 2
-#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE 0
-#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_DISABLE 1
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE 0
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_DISABLE 1
+#define XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE_INTROSPECTION 2
/*
* Sharing ENOMEM helper.
--
1.7.9.5
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