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Commit 8ae09912 authored by Avi Kivity's avatar Avi Kivity Committed by Marcelo Tosatti
Browse files

KVM: Optimize kvm_read_cr[04]_bits() 



'mask' is always a constant, so we can check whether it includes a bit that
might be owned by the guest very cheaply, and avoid the decache call.  Saves
a few hundred bytes of module text.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent f6801dff

arch/x86/kvm/kvm_cache_regs.h

+9 −2
Original line number Diff line number Diff line 
#ifndef ASM_KVM_CACHE_REGS_H

#define ASM_KVM_CACHE_REGS_H



#define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS

#define KVM_POSSIBLE_CR4_GUEST_BITS				  \

	(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR  \

	 | X86_CR4_OSXMMEXCPT | X86_CR4_PGE)



static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu,

					      enum kvm_reg reg)

{
@@ -40,7 +45,8 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index) 


static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)

{

	if (mask & vcpu->arch.cr0_guest_owned_bits)

	ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS;

	if (tmask & vcpu->arch.cr0_guest_owned_bits)

		kvm_x86_ops->decache_cr0_guest_bits(vcpu);

	return vcpu->arch.cr0 & mask;

}
@@ -52,7 +58,8 @@ static inline ulong kvm_read_cr0(struct kvm_vcpu *vcpu) 


static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask)

{

	if (mask & vcpu->arch.cr4_guest_owned_bits)

	ulong tmask = mask & KVM_POSSIBLE_CR4_GUEST_BITS;

	if (tmask & vcpu->arch.cr4_guest_owned_bits)

		kvm_x86_ops->decache_cr4_guest_bits(vcpu);

	return vcpu->arch.cr4 & mask;

}