From: Jan Beulich <jbeulich@suse.com>
Date: Tue, 30 May 2023 09:56:22 +0000 (+0200)
Subject: VMX/cpu-policy: disable RDTSCP and INVPCID insns as needed
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=e56f2106b6727223bd7de03e20fedd1f94da655d;p=people%2Froyger%2Fxen.git

VMX/cpu-policy: disable RDTSCP and INVPCID insns as needed

When either feature is available in hardware, but disabled for a guest,
the respective insn would better cause #UD if attempted to be used.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 9dc16d0cc6..40767b94c3 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -785,6 +785,30 @@ static void cf_check vmx_cpuid_policy_changed(struct vcpu *v)
     vmx_vmcs_enter(v);
     vmx_update_exception_bitmap(v);
 
+    if ( cp->extd.rdtscp )
+    {
+        v->arch.hvm.vmx.secondary_exec_control |= SECONDARY_EXEC_ENABLE_RDTSCP;
+        vmx_update_secondary_exec_control(v);
+    }
+    else if ( v->arch.hvm.vmx.secondary_exec_control &
+              SECONDARY_EXEC_ENABLE_RDTSCP )
+    {
+        v->arch.hvm.vmx.secondary_exec_control &= ~SECONDARY_EXEC_ENABLE_RDTSCP;
+        vmx_update_secondary_exec_control(v);
+    }
+
+    if ( cp->feat.invpcid )
+    {
+        v->arch.hvm.vmx.secondary_exec_control |= SECONDARY_EXEC_ENABLE_INVPCID;
+        vmx_update_secondary_exec_control(v);
+    }
+    else if ( v->arch.hvm.vmx.secondary_exec_control &
+              SECONDARY_EXEC_ENABLE_INVPCID )
+    {
+        v->arch.hvm.vmx.secondary_exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
+        vmx_update_secondary_exec_control(v);
+    }
+
     /*
      * We can safely pass MSR_SPEC_CTRL through to the guest, even if STIBP
      * isn't enumerated in hardware, as SPEC_CTRL_STIBP is ignored.