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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] x86/hvm: Add debug exception vm_events
Since in-guest debug exceptions are now unconditionally trapped to Xen, adding
a hook for vm_event subscribers to tap into this new always-on guest event. We
rename along the way hvm_event_breakpoint_type to hvm_event_type to better
match the various events that can be passed with it. We also introduce the
necessary monitor_op domctl's to enable subscribing to the events.
Signed-off-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
---
tools/libxc/include/xenctrl.h | 3 +-
tools/libxc/xc_monitor.c | 15 +++++++++
tools/tests/xen-access/xen-access.c | 61 +++++++++++++++++++++++++++++++++----
xen/arch/x86/hvm/event.c | 26 ++++++++++++++--
xen/arch/x86/hvm/vmx/vmx.c | 24 ++++++++++++---
xen/arch/x86/monitor.c | 16 ++++++++++
xen/include/asm-x86/domain.h | 2 ++
xen/include/asm-x86/hvm/event.h | 7 +++--
xen/include/asm-x86/vm_event.h | 3 +-
xen/include/public/domctl.h | 6 ++++
xen/include/public/vm_event.h | 12 +++++++-
11 files changed, 156 insertions(+), 19 deletions(-)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index f5a034a..8d70fed 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2190,7 +2190,8 @@ int xc_monitor_software_breakpoint(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_debug_exceptions(xc_interface *xch, domid_t domain_id,
+ bool enable, bool sync);
/**
* This function enables / disables emulation for each REP for a
* REP-compatible instruction.
diff --git a/tools/libxc/xc_monitor.c b/tools/libxc/xc_monitor.c
index b1705dd..e33b40b 100644
--- a/tools/libxc/xc_monitor.c
+++ b/tools/libxc/xc_monitor.c
@@ -156,3 +156,18 @@ int xc_monitor_emulate_each_rep(xc_interface *xch, domid_t
domain_id,
return do_domctl(xch, &domctl);
}
+
+int xc_monitor_debug_exceptions(xc_interface *xch, domid_t domain_id,
+ bool enable, bool sync)
+{
+ 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_DEBUG_EXCEPTION;
+ domctl.u.monitor_op.u.debug_exception.sync = sync;
+
+ return do_domctl(xch, &domctl);
+}
diff --git a/tools/tests/xen-access/xen-access.c
b/tools/tests/xen-access/xen-access.c
index f26e723..cb18a85 100644
--- a/tools/tests/xen-access/xen-access.c
+++ b/tools/tests/xen-access/xen-access.c
@@ -53,6 +53,10 @@
#define ERROR(a, b...) fprintf(stderr, a "\n", ## b)
#define PERROR(a, b...) fprintf(stderr, a ": %s\n", ## b, strerror(errno))
+/* From xen/include/asm-x86/processor.h */
+#define X86_TRAP_DEBUG 1
+#define X86_TRAP_INT3 3
+
typedef struct vm_event {
domid_t domain_id;
xenevtchn_handle *xce_handle;
@@ -333,7 +337,7 @@ void usage(char* progname)
{
fprintf(stderr, "Usage: %s [-m] <domain_id> write|exec", progname);
#if defined(__i386__) || defined(__x86_64__)
- fprintf(stderr, "|breakpoint|altp2m_write|altp2m_exec");
+ fprintf(stderr, "|breakpoint|altp2m_write|altp2m_exec|debug");
#endif
fprintf(stderr,
"\n"
@@ -354,10 +358,12 @@ int main(int argc, char *argv[])
xc_interface *xch;
xenmem_access_t default_access = XENMEM_access_rwx;
xenmem_access_t after_first_access = XENMEM_access_rwx;
+ int memaccess = 0;
int required = 0;
int breakpoint = 0;
int shutting_down = 0;
int altp2m = 0;
+ int debug = 0;
uint16_t altp2m_view_id = 0;
char* progname = argv[0];
@@ -391,11 +397,13 @@ int main(int argc, char *argv[])
{
default_access = XENMEM_access_rx;
after_first_access = XENMEM_access_rwx;
+ memaccess = 1;
}
else if ( !strcmp(argv[0], "exec") )
{
default_access = XENMEM_access_rw;
after_first_access = XENMEM_access_rwx;
+ memaccess = 1;
}
#if defined(__i386__) || defined(__x86_64__)
else if ( !strcmp(argv[0], "breakpoint") )
@@ -406,11 +414,17 @@ int main(int argc, char *argv[])
{
default_access = XENMEM_access_rx;
altp2m = 1;
+ memaccess = 1;
}
else if ( !strcmp(argv[0], "altp2m_exec") )
{
default_access = XENMEM_access_rw;
altp2m = 1;
+ memaccess = 1;
+ }
+ else if ( !strcmp(argv[0], "debug") )
+ {
+ debug = 1;
}
#endif
else
@@ -446,7 +460,7 @@ int main(int argc, char *argv[])
}
/* With altp2m we just create a new, restricted view of the memory */
- if ( altp2m )
+ if ( memaccess && altp2m )
{
xen_pfn_t gfn = 0;
unsigned long perm_set = 0;
@@ -493,7 +507,7 @@ int main(int argc, char *argv[])
}
}
- if ( !altp2m )
+ if ( memaccess && !altp2m )
{
/* Set the default access type and convert all pages to it */
rc = xc_set_mem_access(xch, domain_id, default_access, ~0ull, 0);
@@ -524,6 +538,16 @@ int main(int argc, char *argv[])
}
}
+ if ( debug )
+ {
+ rc = xc_monitor_debug_exceptions(xch, domain_id, 1, 1);
+ if ( rc < 0 )
+ {
+ ERROR("Error %d setting debug exception listener with vm_event\n",
rc);
+ goto exit;
+ }
+ }
+
/* Wait for access */
for (;;)
{
@@ -535,6 +559,9 @@ int main(int argc, char *argv[])
if ( breakpoint )
rc = xc_monitor_software_breakpoint(xch, domain_id, 0);
+ if ( debug )
+ rc = xc_monitor_debug_exceptions(xch, domain_id, 0, 0);
+
if ( altp2m )
{
rc = xc_altp2m_switch_to_view( xch, domain_id, 0 );
@@ -641,9 +668,10 @@ int main(int argc, char *argv[])
req.vcpu_id);
/* Reinject */
- rc = xc_hvm_inject_trap(
- xch, domain_id, req.vcpu_id, 3,
- HVMOP_TRAP_sw_exc, -1, 0, 0);
+ rc = xc_hvm_inject_trap(xch, domain_id, req.vcpu_id,
+ X86_TRAP_INT3,
+ req.u.software_breakpoint.type, -1,
+ req.u.software_breakpoint.insn_length,
0);
if (rc < 0)
{
ERROR("Error %d injecting breakpoint\n", rc);
@@ -669,6 +697,27 @@ int main(int argc, char *argv[])
rsp.flags |= VM_EVENT_FLAG_TOGGLE_SINGLESTEP;
break;
+ case VM_EVENT_REASON_DEBUG_EXCEPTION:
+ printf("Debug exception: rip=%016"PRIx64", vcpu %d. Type: %u.
Length: %u\n",
+ req.data.regs.x86.rip,
+ req.vcpu_id,
+ req.u.debug_exception.type,
+ req.u.debug_exception.insn_length);
+
+ /* Reinject */
+ rc = xc_hvm_inject_trap(xch, domain_id, req.vcpu_id,
+ X86_TRAP_DEBUG,
+ req.u.debug_exception.type, -1,
+ req.u.debug_exception.insn_length,
+ req.data.regs.x86.cr2);
+ if (rc < 0)
+ {
+ ERROR("Error %d injecting breakpoint\n", rc);
+ interrupted = -1;
+ continue;
+ }
+
+ break;
default:
fprintf(stderr, "UNKNOWN REASON CODE %d\n", req.reason);
}
diff --git a/xen/arch/x86/hvm/event.c b/xen/arch/x86/hvm/event.c
index 56c5514..0251d7d 100644
--- a/xen/arch/x86/hvm/event.c
+++ b/xen/arch/x86/hvm/event.c
@@ -87,12 +87,14 @@ static inline unsigned long gfn_of_rip(unsigned long rip)
return paging_gva_to_gfn(curr, sreg.base + rip, &pfec);
}
-int hvm_event_breakpoint(unsigned long rip,
- enum hvm_event_breakpoint_type type)
+int hvm_monitor_event(unsigned long rip, enum hvm_event_type type,
+ unsigned long trap_type, unsigned long insn_length)
{
struct vcpu *curr = current;
struct arch_domain *ad = &curr->domain->arch;
vm_event_request_t req = {};
+ bool_t sync;
+ int rc;
switch ( type )
{
@@ -101,6 +103,9 @@ int hvm_event_breakpoint(unsigned long rip,
return 0;
req.reason = VM_EVENT_REASON_SOFTWARE_BREAKPOINT;
req.u.software_breakpoint.gfn = gfn_of_rip(rip);
+ req.u.software_breakpoint.type = trap_type;
+ req.u.software_breakpoint.insn_length = insn_length;
+ sync = 1;
break;
case HVM_EVENT_SINGLESTEP_BREAKPOINT:
@@ -108,6 +113,17 @@ int hvm_event_breakpoint(unsigned long rip,
return 0;
req.reason = VM_EVENT_REASON_SINGLESTEP;
req.u.singlestep.gfn = gfn_of_rip(rip);
+ sync = 1;
+ break;
+
+ case HVM_EVENT_DEBUG_EXCEPTION:
+ if ( !ad->monitor.debug_exception_enabled )
+ return 0;
+ req.reason = VM_EVENT_REASON_DEBUG_EXCEPTION;
+ req.u.debug_exception.gfn = gfn_of_rip(rip);
+ req.u.debug_exception.type = trap_type;
+ req.u.debug_exception.insn_length = insn_length;
+ sync = !!ad->monitor.debug_exception_sync;
break;
default:
@@ -116,7 +132,11 @@ int hvm_event_breakpoint(unsigned long rip,
req.vcpu_id = curr->vcpu_id;
- return vm_event_monitor_traps(curr, 1, &req);
+ rc = vm_event_monitor_traps(curr, sync, &req);
+ if ( rc == 1 && type == HVM_EVENT_DEBUG_EXCEPTION && !sync )
+ rc = 0;
+
+ return rc;
}
/*
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index bc4410f..38788ad 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3373,9 +3373,24 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
HVMTRACE_1D(TRAP_DEBUG, exit_qualification);
write_debugreg(6, exit_qualification | DR_STATUS_RESERVED_ONE);
if ( !v->domain->debugger_attached )
- vmx_propagate_intr(intr_info);
+ {
+ unsigned long insn_length = 0;
+ int handled;
+ unsigned long trap_type = MASK_EXTR(intr_info,
+ INTR_INFO_INTR_TYPE_MASK);
+
+ if( trap_type >= X86_EVENTTYPE_SW_INTERRUPT )
+ __vmread(VM_EXIT_INSTRUCTION_LEN, &insn_length);
+
+ handled = hvm_monitor_event(regs->eip,
HVM_EVENT_DEBUG_EXCEPTION,
+ trap_type, insn_length);
+ if ( handled <= 0 )
+ vmx_propagate_intr(intr_info);
+
+ }
else
domain_pause_for_debugger();
+
break;
case TRAP_int3:
{
@@ -3389,8 +3404,9 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
}
else {
int handled =
- hvm_event_breakpoint(regs->eip,
- HVM_EVENT_SOFTWARE_BREAKPOINT);
+ hvm_monitor_event(regs->eip,
+ HVM_EVENT_SOFTWARE_BREAKPOINT,
+ X86_EVENTTYPE_SW_EXCEPTION, 1);
if ( handled < 0 )
{
@@ -3717,7 +3733,7 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
vmx_update_cpu_exec_control(v);
if ( v->arch.hvm_vcpu.single_step )
{
- hvm_event_breakpoint(regs->eip, HVM_EVENT_SINGLESTEP_BREAKPOINT);
+ hvm_monitor_event(regs->eip, HVM_EVENT_SINGLESTEP_BREAKPOINT, 0,
0);
if ( v->domain->debugger_attached )
domain_pause_for_debugger();
}
diff --git a/xen/arch/x86/monitor.c b/xen/arch/x86/monitor.c
index 1fec412..36ccb11 100644
--- a/xen/arch/x86/monitor.c
+++ b/xen/arch/x86/monitor.c
@@ -124,6 +124,22 @@ int arch_monitor_domctl_event(struct domain *d,
break;
}
+ case XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION:
+ {
+ bool_t old_status = ad->monitor.debug_exception_enabled;
+
+ if ( unlikely(old_status == requested_status) )
+ return -EEXIST;
+
+ domain_pause(d);
+ ad->monitor.debug_exception_enabled = requested_status;
+ ad->monitor.debug_exception_sync = requested_status ?
+ mop->u.debug_exception.sync :
+ 0;
+ domain_unpause(d);
+ break;
+ }
+
default:
/*
* Should not be reached unless vm_event_monitor_get_capabilities() is
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 165e533..1cf97c3 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -405,6 +405,8 @@ struct arch_domain
unsigned int mov_to_msr_extended : 1;
unsigned int singlestep_enabled : 1;
unsigned int software_breakpoint_enabled : 1;
+ unsigned int debug_exception_enabled : 1;
+ unsigned int debug_exception_sync : 1;
} monitor;
/* Mem_access emulation control */
diff --git a/xen/include/asm-x86/hvm/event.h b/xen/include/asm-x86/hvm/event.h
index 03f7fee..a8f5909 100644
--- a/xen/include/asm-x86/hvm/event.h
+++ b/xen/include/asm-x86/hvm/event.h
@@ -23,10 +23,11 @@
#include <xen/paging.h>
#include <public/vm_event.h>
-enum hvm_event_breakpoint_type
+enum hvm_event_type
{
HVM_EVENT_SOFTWARE_BREAKPOINT,
HVM_EVENT_SINGLESTEP_BREAKPOINT,
+ HVM_EVENT_DEBUG_EXCEPTION,
};
/*
@@ -39,8 +40,8 @@ bool_t hvm_event_cr(unsigned int index, unsigned long value,
#define hvm_event_crX(cr, new, old) \
hvm_event_cr(VM_EVENT_X86_##cr, new, old)
void hvm_event_msr(unsigned int msr, uint64_t value);
-int hvm_event_breakpoint(unsigned long rip,
- enum hvm_event_breakpoint_type type);
+int hvm_monitor_event(unsigned long rip, enum hvm_event_type type,
+ unsigned long trap_type, unsigned long insn_length);
#endif /* __ASM_X86_HVM_EVENT_H__ */
diff --git a/xen/include/asm-x86/vm_event.h b/xen/include/asm-x86/vm_event.h
index 0470240..be6ac28 100644
--- a/xen/include/asm-x86/vm_event.h
+++ b/xen/include/asm-x86/vm_event.h
@@ -58,7 +58,8 @@ static inline uint32_t
vm_event_monitor_get_capabilities(struct domain *d)
capabilities = (1U << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) |
(1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
(1U << XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT) |
- (1U << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST);
+ (1U << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST) |
+ (1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION);
/* 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 2457698..2050441 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1080,6 +1080,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_psr_cmt_op_t);
#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
struct xen_domctl_monitor_op {
uint32_t op; /* XEN_DOMCTL_MONITOR_OP_* */
@@ -1115,6 +1116,11 @@ struct xen_domctl_monitor_op {
/* Pause vCPU until response */
uint8_t sync;
} guest_request;
+
+ struct {
+ /* Pause vCPU until response */
+ uint8_t sync;
+ } debug_exception;
} u;
};
typedef struct xen_domctl_monitor_op xen_domctl_monitor_op_t;
diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
index 9270d52..67387fc 100644
--- a/xen/include/public/vm_event.h
+++ b/xen/include/public/vm_event.h
@@ -119,6 +119,8 @@
#define VM_EVENT_REASON_SINGLESTEP 7
/* An event has been requested via HVMOP_guest_request_vm_event. */
#define VM_EVENT_REASON_GUEST_REQUEST 8
+/* A debug exception was caught */
+#define VM_EVENT_REASON_DEBUG_EXCEPTION 9
/* Supported values for the vm_event_write_ctrlreg index. */
#define VM_EVENT_X86_CR0 0
@@ -203,8 +205,15 @@ struct vm_event_write_ctrlreg {
uint64_t old_value;
};
+struct vm_event_singlestep {
+ uint64_t gfn;
+};
+
struct vm_event_debug {
uint64_t gfn;
+ uint8_t type; /* HVMOP_TRAP_* */
+ uint8_t insn_length;
+ uint8_t _pad[6];
};
struct vm_event_mov_to_msr {
@@ -248,7 +257,8 @@ typedef struct vm_event_st {
struct vm_event_write_ctrlreg write_ctrlreg;
struct vm_event_mov_to_msr mov_to_msr;
struct vm_event_debug software_breakpoint;
- struct vm_event_debug singlestep;
+ struct vm_event_singlestep singlestep;
+ struct vm_event_debug debug_exception;
} u;
union {
--
2.1.4
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