[Xen-devel] [PATCH RESEND v1 7/7] x86: Disable Intel Processor Trace when VMXON in L1 guest

[Luwei Kang <luwei.kang@xxxxxxxxx>]

Disable intel Processor Trace VMX operation(IA32_VMX_MISC[bit 14] is 0)
in L1 guest. As mentioned in SDM, on these type of processors, execution
of the VMXON instruction will  clears IA32_RTIT_CTL.TraceEn and any
attempt to write IA32_RTIT_CTL causes a general-protection xception (#GP).

Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 885eab3..86ccfda 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1516,6 +1516,9 @@ int nvmx_handle_vmxon(struct cpu_user_regs *regs)
     v->arch.hvm_vmx.launched = 0;
     vmsucceed(regs);
 
+    if ( v->arch.hvm_vmx.pt_desc.intel_pt_enabled )
+        pt_set_rtit_ctl(&v->arch.hvm_vmx.pt_desc, 0);
+
     return X86EMUL_OKAY;
 }
 
@@ -2140,8 +2143,8 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 
*msr_content)
         data = hvm_cr4_guest_valid_bits(v, 0);
         break;
     case MSR_IA32_VMX_MISC:
-        /* Do not support CR3-target feature now */
-        data = host_data & ~VMX_MISC_CR3_TARGET;
+        /* Do not support CR3-target and PT VMX feature now */
+        data = host_data & ~(VMX_MISC_CR3_TARGET | VMX_MISC_PT_ENABLE);
         break;
     case MSR_IA32_VMX_EPT_VPID_CAP:
         data = nept_get_ept_vpid_cap();
-- 
1.8.3.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel