[Xen-devel] [PATCH v3 4/4] hvm/svm: Enable CR events

[Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>]

The CR_INTERCEPT_CR3_WRITE intercept is out of the vmcb->_cr_intercepts
so the AMD arch can't intercept CR events.

This patch implements the CR intercept by adding the flag on a
write_ctrlreg event. The monitor write ctrlreg event is moved from the
Intel side to the common capabilities side.

We just need to enable the SVM intercept and then hvm_mov_to_cr() will
forward the event on to the monitor when appropriate.

Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c    | 11 +++++++++++
 xen/include/asm-x86/monitor.h |  6 +++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 5092b12..89c628e 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -60,6 +60,7 @@
 #include <asm/apic.h>
 #include <asm/debugger.h>
 #include <asm/hvm/monitor.h>
+#include <asm/monitor.h>
 #include <asm/xstate.h>
 
 void svm_asm_do_resume(void);
@@ -560,6 +561,16 @@ void svm_update_guest_cr(struct vcpu *v, unsigned int cr)
                 svm_fpu_enter(v);
         }
 
+        if ( paging_mode_hap(v->domain) )
+        {
+            uint32_t intercepts = vmcb_get_cr_intercepts(vmcb);
+
+            /* Trap CR3 updates if CR3 memory events are enabled. */
+            if ( v->domain->arch.monitor.write_ctrlreg_enabled &
+                 monitor_ctrlreg_bitmask(VM_EVENT_X86_CR3) )
+               vmcb_set_cr_intercepts(vmcb, intercepts | 
CR_INTERCEPT_CR3_WRITE);
+        }
+
         value = v->arch.hvm_vcpu.guest_cr[0] | hw_cr0_mask;
         if ( !paging_mode_hap(v->domain) )
             value |= X86_CR0_PG | X86_CR0_WP;
diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
index 6b886af..217f3d4 100644
--- a/xen/include/asm-x86/monitor.h
+++ b/xen/include/asm-x86/monitor.h
@@ -79,12 +79,12 @@ static inline uint32_t arch_monitor_get_capabilities(struct 
domain *d)
 
     capabilities = ((1U << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST) |
                    (1U << XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT) |
-                   (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR));
+                   (1U << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
+                   (1U << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG));
 
     if( cpu_has_vmx )
     {
-        capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) |
-                       (1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
+        capabilities |= (1U << XEN_DOMCTL_MONITOR_EVENT_DEBUG_EXCEPTION) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_CPUID) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_INTERRUPT) |
                        (1U << XEN_DOMCTL_MONITOR_EVENT_EMUL_UNIMPLEMENTED);
-- 
2.7.4


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