[Xen-devel] [PATCH] x86/monitor: Include EAX/ECX in CPUID monitor events

[Tamas K Lengyel <tamas.lengyel@xxxxxxxxxxxx>]

Extend the CPUID monitor event to include EAX and ECX values that were used
when CPUID was executed. This is useful in identifying which leaf was queried.
We also adjust the xen-access output format to more closely resemble the output
of the Linux cpuid tool's raw format.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxxxxx>
---
Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 tools/tests/xen-access/xen-access.c | 4 +++-
 xen/arch/x86/hvm/monitor.c          | 5 ++++-
 xen/arch/x86/hvm/vmx/vmx.c          | 7 ++++++-
 xen/include/asm-x86/hvm/monitor.h   | 3 ++-
 xen/include/public/vm_event.h       | 7 +++++++
 5 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/tools/tests/xen-access/xen-access.c 
b/tools/tests/xen-access/xen-access.c
index ebb63b1..b51b62c 100644
--- a/tools/tests/xen-access/xen-access.c
+++ b/tools/tests/xen-access/xen-access.c
@@ -735,10 +735,12 @@ int main(int argc, char *argv[])
                 break;
             case VM_EVENT_REASON_CPUID:
                 printf("CPUID executed: rip=%016"PRIx64", vcpu %d. Insn 
length: %"PRIu32" " \
-                       "EAX: 0x%"PRIx64" EBX: 0x%"PRIx64" ECX: 0x%"PRIx64" 
EDX: 0x%"PRIx64"\n",
+                       "0x%"PRIx32" 0x%"PRIx32": EAX=0x%"PRIx64" 
EBX=0x%"PRIx64" ECX=0x%"PRIx64" EDX=0x%"PRIx64"\n",
                        req.data.regs.x86.rip,
                        req.vcpu_id,
                        req.u.cpuid.insn_length,
+                       req.u.cpuid.eax,
+                       req.u.cpuid.ecx,
                        req.data.regs.x86.rax,
                        req.data.regs.x86.rbx,
                        req.data.regs.x86.rcx,
diff --git a/xen/arch/x86/hvm/monitor.c b/xen/arch/x86/hvm/monitor.c
index 7277c12..6540e2b 100644
--- a/xen/arch/x86/hvm/monitor.c
+++ b/xen/arch/x86/hvm/monitor.c
@@ -136,7 +136,8 @@ int hvm_monitor_debug(unsigned long rip, enum 
hvm_monitor_debug_type type,
     return monitor_traps(curr, sync, &req);
 }
 
-int hvm_monitor_cpuid(unsigned long insn_length)
+int hvm_monitor_cpuid(unsigned long insn_length, unsigned int eax,
+                      unsigned int ecx)
 {
     struct vcpu *curr = current;
     struct arch_domain *ad = &curr->domain->arch;
@@ -148,6 +149,8 @@ int hvm_monitor_cpuid(unsigned long insn_length)
     req.reason = VM_EVENT_REASON_CPUID;
     req.vcpu_id = curr->vcpu_id;
     req.u.cpuid.insn_length = insn_length;
+    req.u.cpuid.eax = eax;
+    req.u.cpuid.ecx = ecx;
 
     return monitor_traps(curr, 1, &req);
 }
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 3d330b6..6df7612 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2402,12 +2402,17 @@ static void vmx_cpuid_intercept(
 static int vmx_do_cpuid(struct cpu_user_regs *regs)
 {
     unsigned int eax, ebx, ecx, edx;
+    unsigned int _eax, _ecx;
 
     eax = regs->eax;
     ebx = regs->ebx;
     ecx = regs->ecx;
     edx = regs->edx;
 
+    /* The CPUID monitor needs both the old and new values of EAX and ECX */
+    _eax = regs->eax;
+    _ecx = regs->ecx;
+
     vmx_cpuid_intercept(&eax, &ebx, &ecx, &edx);
 
     regs->eax = eax;
@@ -2415,7 +2420,7 @@ static int vmx_do_cpuid(struct cpu_user_regs *regs)
     regs->ecx = ecx;
     regs->edx = edx;
 
-    return hvm_monitor_cpuid(get_instruction_length());
+    return hvm_monitor_cpuid(get_instruction_length(), _eax, _ecx);;
 }
 
 static void vmx_dr_access(unsigned long exit_qualification,
diff --git a/xen/include/asm-x86/hvm/monitor.h 
b/xen/include/asm-x86/hvm/monitor.h
index a92f3fc..cdcbeca 100644
--- a/xen/include/asm-x86/hvm/monitor.h
+++ b/xen/include/asm-x86/hvm/monitor.h
@@ -40,7 +40,8 @@ bool_t hvm_monitor_cr(unsigned int index, unsigned long value,
 void hvm_monitor_msr(unsigned int msr, uint64_t value);
 int hvm_monitor_debug(unsigned long rip, enum hvm_monitor_debug_type type,
                       unsigned long trap_type, unsigned long insn_length);
-int hvm_monitor_cpuid(unsigned long insn_length);
+int hvm_monitor_cpuid(unsigned long insn_length, unsigned int eax,
+                      unsigned int ecx);
 
 #endif /* __ASM_X86_HVM_MONITOR_H__ */
 
diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
index 64e6857..e0fee23 100644
--- a/xen/include/public/vm_event.h
+++ b/xen/include/public/vm_event.h
@@ -226,6 +226,13 @@ struct vm_event_mov_to_msr {
 
 struct vm_event_cpuid {
     uint32_t insn_length;
+    /*
+     * Value of EAX and ECX when CPUID was executed.
+     * Note that the resulting register values are accessible in
+     * vm_event_regs_x86.
+     */
+    uint32_t eax;
+    uint32_t ecx;
     uint32_t _pad;
 };
 
-- 
2.9.3


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