KVM: nVMX: Add preemption timer support

Provided the host has this feature, it's straightforward to offer it to
the guest as well. We just need to load to timer value on L2 entry if
the feature was enabled by L1 and watch out for the corresponding exit
reason.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

2 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 056bda586a45..fc1c3134473b 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -70,6 +70,7 @@
 #define PIN_BASED_EXT_INTR_MASK                 0x00000001
 #define PIN_BASED_NMI_EXITING                   0x00000008
 #define PIN_BASED_VIRTUAL_NMIS                  0x00000020
+#define PIN_BASED_VMX_PREEMPTION_TIMER          0x00000040
 
 #define PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR     0x00000016
 
@@ -95,6 +96,7 @@
 
 #define VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR      0x000011ff
 
+#define VMX_MISC_PREEMPTION_TIMER_RATE_MASK     0x0000001f
 #define VMX_MISC_SAVE_EFER_LMA                  0x00000020
 
 /* VMCS Encodings */
@@ -217,6 +219,7 @@ enum vmcs_field {
         GUEST_INTERRUPTIBILITY_INFO     = 0x00004824,
         GUEST_ACTIVITY_STATE            = 0X00004826,
         GUEST_SYSENTER_CS               = 0x0000482A,
+        VMX_PREEMPTION_TIMER_VALUE      = 0x0000482E,
         HOST_IA32_SYSENTER_CS           = 0x00004c00,
         CR0_GUEST_HOST_MASK             = 0x00006000,
         CR4_GUEST_HOST_MASK             = 0x00006002,
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index 2871fccfee68..d651082c7cf7 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -65,6 +65,7 @@
 #define EXIT_REASON_EOI_INDUCED         45
 #define EXIT_REASON_EPT_VIOLATION       48
 #define EXIT_REASON_EPT_MISCONFIG       49
+#define EXIT_REASON_PREEMPTION_TIMER    52
 #define EXIT_REASON_WBINVD              54
 #define EXIT_REASON_XSETBV              55
 #define EXIT_REASON_APIC_WRITE          56
@@ -110,7 +111,7 @@
         { EXIT_REASON_EOI_INDUCED,           "EOI_INDUCED" }, \
         { EXIT_REASON_INVALID_STATE,         "INVALID_STATE" }, \
         { EXIT_REASON_INVD,                  "INVD" }, \
-        { EXIT_REASON_INVPCID,               "INVPCID" }
-
+        { EXIT_REASON_INVPCID,               "INVPCID" }, \
+        { EXIT_REASON_PREEMPTION_TIMER,      "PREEMPTION_TIMER" }
 
 #endif /* _UAPIVMX_H */