KVM: x86: Add Intel PT virtualization work mode

Intel Processor Trace virtualization can be work in one
of 2 possible modes:

a. System-Wide mode (default):
   When the host configures Intel PT to collect trace packets
   of the entire system, it can leave the relevant VMX controls
   clear to allow VMX-specific packets to provide information
   across VMX transitions.
   KVM guest will not aware this feature in this mode and both
   host and KVM guest trace will output to host buffer.

b. Host-Guest mode:
   Host can configure trace-packet generation while in
   VMX non-root operation for guests and root operation
   for native executing normally.
   Intel PT will be exposed to KVM guest in this mode, and
   the trace output to respective buffer of host and guest.
   In this mode, tht status of PT will be saved and disabled
   before VM-entry and restored after VM-exit if trace
   a virtual machine.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index f932d7c971e9..86eb9c887386 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -5,6 +5,7 @@
 #include <linux/kvm_host.h>
 
 #include <asm/kvm.h>
+#include <asm/intel_pt.h>
 
 #include "capabilities.h"
 #include "ops.h"
@@ -421,13 +422,19 @@ static inline void vmx_segment_cache_clear(struct vcpu_vmx *vmx)
 
 static inline u32 vmx_vmentry_ctrl(void)
 {
+	u32 vmentry_ctrl = vmcs_config.vmentry_ctrl;
+	if (pt_mode == PT_MODE_SYSTEM)
+		vmentry_ctrl &= ~(VM_EXIT_PT_CONCEAL_PIP | VM_EXIT_CLEAR_IA32_RTIT_CTL);
 	/* Loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically */
-	return vmcs_config.vmentry_ctrl &
+	return vmentry_ctrl &
 		~(VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL | VM_ENTRY_LOAD_IA32_EFER);
 }
 
 static inline u32 vmx_vmexit_ctrl(void)
 {
+	u32 vmexit_ctrl = vmcs_config.vmexit_ctrl;
+	if (pt_mode == PT_MODE_SYSTEM)
+		vmexit_ctrl &= ~(VM_ENTRY_PT_CONCEAL_PIP | VM_ENTRY_LOAD_IA32_RTIT_CTL);
 	/* Loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically */
 	return vmcs_config.vmexit_ctrl &
 		~(VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL | VM_EXIT_LOAD_IA32_EFER);