[Xen-devel] [PATCH 2/6] x86: configure vmcs for Intel processor trace virtualization

[Luwei Kang <luwei.kang@xxxxxxxxx>]

This patch configure VMCS to make Intel PT output address can be
treat as guest physical address and translated by EPT when
intel_pt option is true.
There have some constraint condition on VMCS configuration,
otherwise will cause VM entry failed.

1. If the “Guest PT uses Guest Physical Addresses” execution
   control is 1, the “Clear IA32_RTIT_CTL on exit” exit
   control and the “Load IA32_RTIT_CTL on entry” entry
   control must also be 1.

2. If the “Guest PT uses Guest Physical Addresses” execution
   control is 1, the "enable EPT" execution control must
   also be 1.

Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c        | 36 +++++++++++++++++++++++++++++++-----
 xen/include/asm-x86/hvm/vmx/vmcs.h |  7 +++++++
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index f62fe7e..8cd57b5 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -40,6 +40,7 @@
 #include <asm/shadow.h>
 #include <asm/tboot.h>
 #include <asm/apic.h>
+#include <asm/intel_pt.h>
 
 static bool_t __read_mostly opt_vpid_enabled = 1;
 boolean_param("vpid", opt_vpid_enabled);
@@ -242,6 +243,9 @@ static int vmx_init_vmcs_config(void)
         rdmsrl(MSR_IA32_VMX_MISC, _vmx_misc_cap);
         if ( _vmx_misc_cap & VMX_MISC_VMWRITE_ALL )
             opt |= SECONDARY_EXEC_ENABLE_VMCS_SHADOWING;
+        if ( _vmx_misc_cap & VMX_MISC_PT_ENABLE )
+            opt |= SECONDARY_EXEC_PT_USE_GPA |
+                   SECONDARY_EXEC_CONCEAL_PT_PIP;
         if ( opt_vpid_enabled )
             opt |= SECONDARY_EXEC_ENABLE_VPID;
         if ( opt_unrestricted_guest_enabled )
@@ -343,7 +347,8 @@ static int vmx_init_vmcs_config(void)
 
     min = VM_EXIT_ACK_INTR_ON_EXIT;
     opt = VM_EXIT_SAVE_GUEST_PAT | VM_EXIT_LOAD_HOST_PAT |
-          VM_EXIT_CLEAR_BNDCFGS;
+          VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_CONCEAL_PT_PIP |
+          VM_EXIT_CLEAR_IA32_RTIT_CTL;
     min |= VM_EXIT_IA32E_MODE;
     _vmx_vmexit_control = adjust_vmx_controls(
         "VMExit Control", min, opt, MSR_IA32_VMX_EXIT_CTLS, &mismatch);
@@ -383,13 +388,28 @@ static int vmx_init_vmcs_config(void)
         _vmx_secondary_exec_control &= ~SECONDARY_EXEC_ENABLE_VIRT_EXCEPTIONS;
 
     min = 0;
-    opt = VM_ENTRY_LOAD_GUEST_PAT | VM_ENTRY_LOAD_BNDCFGS;
+    opt = VM_ENTRY_LOAD_GUEST_PAT | VM_ENTRY_LOAD_BNDCFGS |
+          VM_ENTRY_CONCEAL_PT_PIP | VM_ENTRY_LOAD_IA32_RTIT_CTL;
     _vmx_vmentry_control = adjust_vmx_controls(
         "VMEntry Control", min, opt, MSR_IA32_VMX_ENTRY_CTLS, &mismatch);
 
     if ( mismatch )
         return -EINVAL;
 
+    if ( !(_vmx_secondary_exec_control & SECONDARY_EXEC_ENABLE_EPT) ||
+         !(_vmx_secondary_exec_control & SECONDARY_EXEC_PT_USE_GPA) ||
+         !(_vmx_vmexit_control & VM_EXIT_CLEAR_IA32_RTIT_CTL) ||
+         !(_vmx_vmentry_control & VM_ENTRY_LOAD_IA32_RTIT_CTL) )
+    {
+        _vmx_secondary_exec_control &= ~(SECONDARY_EXEC_PT_USE_GPA |
+                                         SECONDARY_EXEC_CONCEAL_PT_PIP);
+        _vmx_vmexit_control &= ~(VM_EXIT_CONCEAL_PT_PIP |
+                                 VM_EXIT_CLEAR_IA32_RTIT_CTL);
+        _vmx_vmentry_control &= ~(VM_ENTRY_CONCEAL_PT_PIP |
+                                  VM_ENTRY_LOAD_IA32_RTIT_CTL);
+        opt_intel_pt = 0;
+    }
+
     if ( !vmx_pin_based_exec_control )
     {
         /* First time through. */
@@ -1032,10 +1052,16 @@ static int construct_vmcs(struct vcpu *v)
         v->arch.hvm_vmx.secondary_exec_control &= 
             ~(SECONDARY_EXEC_ENABLE_EPT | 
               SECONDARY_EXEC_UNRESTRICTED_GUEST |
-              SECONDARY_EXEC_ENABLE_INVPCID);
+              SECONDARY_EXEC_ENABLE_INVPCID |
+              SECONDARY_EXEC_PT_USE_GPA |
+              SECONDARY_EXEC_CONCEAL_PT_PIP);
         vmexit_ctl &= ~(VM_EXIT_SAVE_GUEST_PAT |
-                        VM_EXIT_LOAD_HOST_PAT);
-        vmentry_ctl &= ~VM_ENTRY_LOAD_GUEST_PAT;
+                        VM_EXIT_LOAD_HOST_PAT |
+                        VM_EXIT_CONCEAL_PT_PIP |
+                        VM_EXIT_CLEAR_IA32_RTIT_CTL);
+        vmentry_ctl &= ~(VM_ENTRY_LOAD_GUEST_PAT |
+                         VM_ENTRY_CONCEAL_PT_PIP |
+                         VM_ENTRY_LOAD_IA32_RTIT_CTL);
     }
 
     /* Disable Virtualize x2APIC mode by default. */
diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h 
b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 8fb9e3c..bd8a128 100644
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -220,6 +220,8 @@ extern u32 vmx_pin_based_exec_control;
 #define VM_EXIT_LOAD_HOST_EFER          0x00200000
 #define VM_EXIT_SAVE_PREEMPT_TIMER      0x00400000
 #define VM_EXIT_CLEAR_BNDCFGS           0x00800000
+#define VM_EXIT_CONCEAL_PT_PIP          0x01000000
+#define VM_EXIT_CLEAR_IA32_RTIT_CTL     0x02000000
 extern u32 vmx_vmexit_control;
 
 #define VM_ENTRY_IA32E_MODE             0x00000200
@@ -229,6 +231,8 @@ extern u32 vmx_vmexit_control;
 #define VM_ENTRY_LOAD_GUEST_PAT         0x00004000
 #define VM_ENTRY_LOAD_GUEST_EFER        0x00008000
 #define VM_ENTRY_LOAD_BNDCFGS           0x00010000
+#define VM_ENTRY_CONCEAL_PT_PIP         0x00020000
+#define VM_ENTRY_LOAD_IA32_RTIT_CTL     0x00040000
 extern u32 vmx_vmentry_control;
 
 #define SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES 0x00000001
@@ -247,7 +251,9 @@ extern u32 vmx_vmentry_control;
 #define SECONDARY_EXEC_ENABLE_VMCS_SHADOWING    0x00004000
 #define SECONDARY_EXEC_ENABLE_PML               0x00020000
 #define SECONDARY_EXEC_ENABLE_VIRT_EXCEPTIONS   0x00040000
+#define SECONDARY_EXEC_CONCEAL_PT_PIP           0x00080000
 #define SECONDARY_EXEC_XSAVES                   0x00100000
+#define SECONDARY_EXEC_PT_USE_GPA               0x01000000
 #define SECONDARY_EXEC_TSC_SCALING              0x02000000
 extern u32 vmx_secondary_exec_control;
 
@@ -268,6 +274,7 @@ extern u32 vmx_secondary_exec_control;
 #define VMX_VPID_INVVPID_SINGLE_CONTEXT_RETAINING_GLOBAL 0x80000000000ULL
 extern u64 vmx_ept_vpid_cap;
 
+#define VMX_MISC_PT_ENABLE                      0x00004000
 #define VMX_MISC_CR3_TARGET                     0x01ff0000
 #define VMX_MISC_VMWRITE_ALL                    0x20000000
 
-- 
1.8.3.1


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