Support TrustVisor detection through CPUID

lxylxy123456 · Nov 25, 2022 · ab560c7 · ab560c7
1 parent 5331f23
commit ab560c7
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Showing 5 changed files with 32 additions and 2 deletions.
diff --git a/hypapps/trustvisor/src/appmain.c b/hypapps/trustvisor/src/appmain.c
@@ -729,6 +729,29 @@ void tv_app_handleshutdown(VCPU *vcpu, struct regs __attribute__((unused)) *r)
   xmhf_baseplatform_reboot(vcpu);
 }
 
+/*
+ * Activated when EAX=0x7a567254 (TrVz) and ECX=0.
+ * Set EAX=0x7a767274 (TRVZ).
+ * Set EBX=UINT_MAX if not in PAL, or whitelist_entry.id if in PAL.
+ * Set ECX[0]=0 if calling process is 32-bit, 1 if 64-bit.
+ * Set ECX[1-31]=undefined.
+ * Set EDX=undefined.
+ */
+u32 tv_app_handlecpuid(VCPU *vcpu, struct regs *r)
+{
+  if (r->eax == 0x7a567254U && r->ecx == 0) {
+    r->eax = 0x7a767274U;
+    r->ebx = (u32)hpt_scode_get_scode_id(vcpu);
+    r->ecx = 0U;
+    if (VCPU_g64(vcpu)) {
+      r->ecx |= (1U << 1);
+    }
+    r->edx = 0U;
+    return APP_CPUID_SKIP;
+  }
+  return APP_CPUID_CHAIN;
+}
+
 /* Local Variables: */
 /* mode:c           */
 /* indent-tabs-mode:nil */

diff --git a/hypapps/trustvisor/src/emhf_callbacks.c b/hypapps/trustvisor/src/emhf_callbacks.c
@@ -82,6 +82,5 @@ void xmhf_app_handleshutdown(VCPU *vcpu, struct regs *r)
 // Detect the presence of TrustVisor
 u32 xmhf_app_handlecpuid(VCPU *vcpu, struct regs *r)
 {
-	(void)vcpu;(void)r;
-	return APP_CPUID_CHAIN;
+  return tv_app_handlecpuid(vcpu, r);
 }
diff --git a/hypapps/trustvisor/src/include/scode.h b/hypapps/trustvisor/src/include/scode.h
@@ -162,6 +162,7 @@ int copy_to_current_guest(VCPU * vcpu, gva_t gvaddr, void *src, size_t len);
 u32 hpt_scode_switch_scode(VCPU * vcpu, struct regs *r);
 u32 hpt_scode_switch_regular(VCPU * vcpu);
 u32 hpt_scode_npf(VCPU * vcpu, uintptr_t gpaddr, u64 errorcode, struct regs *r);
+int hpt_scode_get_scode_id(VCPU * vcpu);
 u32 scode_share(VCPU * vcpu, u32 scode_entry, u32 addr, u32 len);
 u32 scode_share_ranges(VCPU * vcpu, u32 scode_entry, u32 gva_base[], u32 gva_len[], u32 count);
 

diff --git a/hypapps/trustvisor/src/include/tv_emhf.h b/hypapps/trustvisor/src/include/tv_emhf.h
@@ -57,5 +57,6 @@ u32 tv_app_handleintercept_hwpgtblviolation(VCPU *vcpu,
 u32 tv_app_handleintercept_portaccess(VCPU *vcpu, struct regs *r,
                                       u32 portnum, u32 access_type, u32 access_size);
 void tv_app_handleshutdown(VCPU *vcpu, struct regs *r);
+u32 tv_app_handlecpuid(VCPU *vcpu, struct regs *r);
 
 #endif
diff --git a/hypapps/trustvisor/src/scode.c b/hypapps/trustvisor/src/scode.c
@@ -1418,6 +1418,12 @@ u32 hpt_scode_npf(VCPU * vcpu, uintptr_t gpaddr, u64 errorcode, struct regs *r)
   return err;
 }
 
+/* Return ID of the scode current CPU is running, or -1 if not running scode */
+int hpt_scode_get_scode_id(VCPU * vcpu)
+{
+  return scode_curr[vcpu->id];
+}
+
 /* caller is responsible for flushing TLB */
 void scode_release_all_shared_pages(VCPU *vcpu, whitelist_entry_t* wle)
 {