KVM: x86: accessors for guest registers

As suggested by Avi, introduce accessors to read/write guest registers.
This simplifies the ->cache_regs/->decache_regs interface, and improves
register caching which is important for VMX, where the cost of
vmcs_read/vmcs_write is significant.

[avi: fix warnings]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
new file mode 100644
index 00000000000..1ff819dce7d
--- /dev/null
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -0,0 +1,32 @@
+#ifndef ASM_KVM_CACHE_REGS_H
+#define ASM_KVM_CACHE_REGS_H
+
+static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu,
+                                              enum kvm_reg reg)
+{
+        if (!test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail))
+                kvm_x86_ops->cache_reg(vcpu, reg);
+
+        return vcpu->arch.regs[reg];
+}
+
+static inline void kvm_register_write(struct kvm_vcpu *vcpu,
+                                      enum kvm_reg reg,
+                                      unsigned long val)
+{
+        vcpu->arch.regs[reg] = val;
+        __set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
+        __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+}
+
+static inline unsigned long kvm_rip_read(struct kvm_vcpu *vcpu)
+{
+        return kvm_register_read(vcpu, VCPU_REGS_RIP);
+}
+
+static inline void kvm_rip_write(struct kvm_vcpu *vcpu, unsigned long val)
+{
+        kvm_register_write(vcpu, VCPU_REGS_RIP, val);
+}
+
+#endif