Messages in this thread | | | Subject | Re: [PATCH 0/2] KVM: X86: Don't reset mmu context when changing PGE or PCID | From | Lai Jiangshan <> | Date | Fri, 15 Oct 2021 00:03:55 +0800 |
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Ping
On 2021/9/19 10:42, Lai Jiangshan wrote: > From: Lai Jiangshan <laijs@linux.alibaba.com> > > This patchset uses kvm_vcpu_flush_tlb_guest() instead of kvm_mmu_reset_context() > when X86_CR4_PGE is changed or X86_CR4_PCIDE is changed 1->0. > > Neither X86_CR4_PGE nor X86_CR4_PCIDE participates in kvm_mmu_role, so > kvm_mmu_reset_context() is not required to be invoked. Only flushing tlb > is required as SDM says. > > The patchset has nothing to do with performance, because the overheads of > kvm_mmu_reset_context() and kvm_vcpu_flush_tlb_guest() are the same. And > even in the [near] future, kvm_vcpu_flush_tlb_guest() will be optimized, > the code is not in the hot path. > > This patchset makes the code more clear when to reset the mmu context. > And it makes KVM_MMU_CR4_ROLE_BITS consistent with kvm_mmu_role. > > Lai Jiangshan (2): > KVM: X86: Don't reset mmu context when X86_CR4_PCIDE 1->0 > KVM: X86: Don't reset mmu context when toggling X86_CR4_PGE > > arch/x86/kvm/mmu.h | 5 ++--- > arch/x86/kvm/x86.c | 7 +++++-- > 2 files changed, 7 insertions(+), 5 deletions(-) >
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