Messages in this thread | | | Date | Thu, 18 Nov 2021 16:53:21 +0800 | Subject | Re: [PATCH 00/15] KVM: X86: Fix and clean up for register caches | From | Lai Jiangshan <> |
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Hello,all
Ping
Thanks Lai
On 2021/11/8 20:43, Lai Jiangshan wrote: > From: Lai Jiangshan <laijs@linux.alibaba.com> > > The patchset was started when I read the code of nested_svm_load_cr3() > and found that it marks CR3 available other than dirty when changing > vcpu->arch.cr3. I thought its caller has ensured that vmcs.GUEST_CR3 > will be or already be set to @cr3 so that it doesn't need to be marked > dirty. And later I found that it is not true and it must be a bug in > a rare case before I realized that all the code just (ab)uses > vcpu->arch.regs_avail for VCPU_EXREG_CR3 and there is not such bug > of using regs_avail here. > (The above finding becomes a low meaning patch_15 rather than a fix) > > The unhappyness of the reading code made me do some cleanup for > regs_avail and regs_dirty and kvm_register_xxx() functions in the hope > that the code become clearer with less misunderstanding. > > Major focus was on VCPU_EXREG_CR3 and VCPU_EXREG_PDPTR. They are > ensured to be marked the correct tags (available or dirty), and the > value is ensured to be synced to architecture before run if it is marked > dirty. > > When cleaning VCPU_EXREG_PDPTR, I also checked if the corresponding > cr0/cr4 pdptr bits are all intercepted when !tdp_enabled, and I think > it is not clear enough, so X86_CR4_PDPTR_BITS is added as self-comments > in the code. > > Lai Jiangshan (15): > KVM: X86: Ensure the dirty PDPTEs to be loaded > KVM: VMX: Mark VCPU_EXREG_PDPTR available in ept_save_pdptrs() > KVM: SVM: Always clear available of VCPU_EXREG_PDPTR in svm_vcpu_run() > KVM: VMX: Add and use X86_CR4_TLB_BITS when !enable_ept > KVM: VMX: Add and use X86_CR4_PDPTR_BITS when !enable_ept > KVM: X86: Move CR0 pdptr_bits into header file as X86_CR0_PDPTR_BITS > KVM: SVM: Remove outdate comment in svm_load_mmu_pgd() > KVM: SVM: Remove useless check in svm_load_mmu_pgd() > KVM: SVM: Remove the unneeded code to mark available for CR3 > KVM: X86: Mark CR3 dirty when vcpu->arch.cr3 is changed > KVM: VMX: Update vmcs.GUEST_CR3 only when the guest CR3 is dirty > KVM: VMX: Reset the bits that are meaningful to be reset in > vmx_register_cache_reset() > KVM: SVM: Add and use svm_register_cache_reset() > KVM: X86: Remove kvm_register_clear_available() > KVM: nVMX: Always write vmcs.GUEST_CR3 during nested VM-Exit > > arch/x86/kvm/kvm_cache_regs.h | 13 ++++++------ > arch/x86/kvm/svm/nested.c | 1 - > arch/x86/kvm/svm/svm.c | 17 ++++++++-------- > arch/x86/kvm/svm/svm.h | 26 ++++++++++++++++++++++++ > arch/x86/kvm/vmx/nested.c | 30 ++++++++++++++++++---------- > arch/x86/kvm/vmx/vmx.c | 12 +++++++----- > arch/x86/kvm/vmx/vmx.h | 37 +++++++++++++++++++++++++---------- > arch/x86/kvm/x86.c | 13 ++++++------ > 8 files changed, 101 insertions(+), 48 deletions(-) >
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