Messages in this thread Patch in this message | | | Date | Mon, 12 Apr 2010 16:03:44 +0800 | From | Xiao Guangrong <> | Subject | [PATCH 4/6] KVM MMU: optimize for writing cr4 |
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Usually, OS changes CR4.PGE bit to flush all global page, under this case, no need reset mmu and just flush tlb
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> --- arch/x86/kvm/x86.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fd5c3d3..2aaa6fb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -463,6 +463,15 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) unsigned long old_cr4 = kvm_read_cr4(vcpu); unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE; + if (cr4 == old_cr4) + return; + + if ((cr4 ^ old_cr4) == X86_CR4_PGE) { + kvm_mmu_sync_roots(vcpu); + kvm_mmu_flush_tlb(vcpu); + return; + } + if (cr4 & CR4_RESERVED_BITS) { kvm_inject_gp(vcpu, 0); return; -- 1.6.1.2
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