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Re: [Xen-devel] [PATCH 3/8] x86/vm-event/monitor: relocate code-motion more appropriately



On 7/4/2016 5:16 PM, Razvan Cojocaru wrote:
On 07/04/16 17:05, Jan Beulich wrote:
On 04.07.16 at 15:22, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
On 07/04/16 13:22, Jan Beulich wrote:
On 30.06.16 at 20:43, <czuzu@xxxxxxxxxxxxxxx> wrote:
@@ -119,6 +156,55 @@ bool_t monitored_msr(const struct domain *d, u32 msr)
      return test_bit(msr, bitmap);
  }
+static void write_ctrlreg_adjust_traps(struct domain *d)
+{
+    struct vcpu *v;
+    struct arch_vmx_struct *avmx;
+    unsigned int cr3_bitmask;
+    bool_t cr3_vmevent, cr3_ldexit;
+
+    /* Adjust CR3 load-exiting. */
+
+    /* vmx only */
+    ASSERT(cpu_has_vmx);
+
+    /* non-hap domains trap CR3 writes unconditionally */
+    if ( !paging_mode_hap(d) )
+    {
+        for_each_vcpu ( d, v )
+            ASSERT(v->arch.hvm_vmx.exec_control & CPU_BASED_CR3_LOAD_EXITING);
+        return;
+    }
+
+    cr3_bitmask = monitor_ctrlreg_bitmask(VM_EVENT_X86_CR3);
+    cr3_vmevent = !!(d->arch.monitor.write_ctrlreg_enabled & cr3_bitmask);
+
+    for_each_vcpu ( d, v )
+    {
+        avmx = &v->arch.hvm_vmx;
+        cr3_ldexit = !!(avmx->exec_control & CPU_BASED_CR3_LOAD_EXITING);
+
+        if ( cr3_vmevent == cr3_ldexit )
+            continue;
+
+        /*
+         * If CR0.PE=0, CR3 load exiting must remain enabled.
+         * See vmx_update_guest_cr code motion for cr = 0.
+         */
+        if ( cr3_ldexit && !hvm_paging_enabled(v) && !vmx_unrestricted_guest(v)
)
+            continue;
+
+        if ( cr3_vmevent )
+            avmx->exec_control |= CPU_BASED_CR3_LOAD_EXITING;
+        else
+            avmx->exec_control &= ~CPU_BASED_CR3_LOAD_EXITING;
+
+        vmx_vmcs_enter(v);
+        vmx_update_cpu_exec_control(v);
+        vmx_vmcs_exit(v);
+    }
+}
While Razvan gave his ack already, I wonder whether it's really a
good idea to put deeply VMX-specific code outside of a VMX-specific
file.
Didn't I add "for monitor / vm_event parts Acked-by: ..."? If I didn't,
I meant to.
Well - this is a monitor file (monitor.c).
Fair enough, I should have been more detailed here. I do see the merit
of your suggestion, and so FWIW I second your suggestion to move the
code to some VMX-specific part of the tree if possible.

But did you also see my reply concerning this suggestion? :-)


Thanks,
Razvan


Thanks,
Corneliu.

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