[PATCH v2 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE

Tao Xu
2019-05-24T07:59:30Z

As the latest Intel 64 and IA-32 Architectures Software Developer's
Manual, UMWAIT and TPAUSE instructions cause a VM exit if the
“RDTSC exiting” and “enable user wait and pause” VM-execution controls
are both 1.

This patch is to handle the vm-exit for UMWAIT and TPAUSE as invalid_op.

Co-developed-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
Signed-off-by: Tao Xu <tao3.xu@intel.com>
---
arch/x86/include/uapi/asm/vmx.h | 6 +++++-
arch/x86/kvm/vmx/vmx.c | 16 ++++++++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index d213ec5c3766..d88d7a68849b 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -85,6 +85,8 @@
#define EXIT_REASON_PML_FULL 62
#define EXIT_REASON_XSAVES 63
#define EXIT_REASON_XRSTORS 64
+#define EXIT_REASON_UMWAIT 67
+#define EXIT_REASON_TPAUSE 68

#define VMX_EXIT_REASONS \
{ EXIT_REASON_EXCEPTION_NMI, "EXCEPTION_NMI" }, \
@@ -142,7 +144,9 @@
{ EXIT_REASON_RDSEED, "RDSEED" }, \
{ EXIT_REASON_PML_FULL, "PML_FULL" }, \
{ EXIT_REASON_XSAVES, "XSAVES" }, \
- { EXIT_REASON_XRSTORS, "XRSTORS" }
+ { EXIT_REASON_XRSTORS, "XRSTORS" }, \
+ { EXIT_REASON_UMWAIT, "UMWAIT" }, \
+ { EXIT_REASON_TPAUSE, "TPAUSE" }

#define VMX_ABORT_SAVE_GUEST_MSR_FAIL 1
#define VMX_ABORT_LOAD_HOST_PDPTE_FAIL 2
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 49e107692aee..0743a4ac2b61 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5337,6 +5337,20 @@ static int handle_monitor(struct kvm_vcpu *vcpu)
return handle_nop(vcpu);
}

+static int handle_umwait(struct kvm_vcpu *vcpu)
+{
+ printk_once(KERN_WARNING "kvm: Can't use UMWAIT instruction "
+ "when RDTSC exiting VM-execution control is enabled!\n");
+ return handle_invalid_op(vcpu);
+}
+
+static int handle_tpause(struct kvm_vcpu *vcpu)
+{
+ printk_once(KERN_WARNING "kvm: Can't use TPAUSE instruction "
+ "when RDTSC exiting VM-execution control is enabled!\n");
+ return handle_invalid_op(vcpu);
+}
+
static int handle_invpcid(struct kvm_vcpu *vcpu)
{
u32 vmx_instruction_info;
@@ -5547,6 +5561,8 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
[EXIT_REASON_VMFUNC] = handle_vmx_instruction,
[EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer,
[EXIT_REASON_ENCLS] = handle_encls,
+ [EXIT_REASON_UMWAIT] = handle_umwait,
+ [EXIT_REASON_TPAUSE] = handle_tpause,
};

static const int kvm_vmx_max_exit_handlers =
--
2.20.1