KVM: Add generic RDPMC support

Add a helper function that emulates the RDPMC instruction operation.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 08ae951ecc5c..27d18b7617f3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -760,6 +760,21 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
 }
 EXPORT_SYMBOL_GPL(kvm_get_dr);
 
+bool kvm_rdpmc(struct kvm_vcpu *vcpu)
+{
+        u32 ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
+        u64 data;
+        int err;
+
+        err = kvm_pmu_read_pmc(vcpu, ecx, &data);
+        if (err)
+                return err;
+        kvm_register_write(vcpu, VCPU_REGS_RAX, (u32)data);
+        kvm_register_write(vcpu, VCPU_REGS_RDX, data >> 32);
+        return err;
+}
+EXPORT_SYMBOL_GPL(kvm_rdpmc);
+
 /*
  * List of msr numbers which we expose to userspace through KVM_GET_MSRS
  * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.