From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> Current code uses mmu->pae_root, mmu->pml4_root, and mmu->pml5_root to setup special roots. The initialization code is complex and the roots are not associated with struct kvm_mmu_page which causes the code more complex. So add new local shadow pages to simplify it. The local shadow pages are associated with struct kvm_mmu_page and VCPU-local. The local shadow pages are created and freed when the roots are changed (or one-off) which can be optimized but not in the patchset since the re-creating is light way (in normal case only the struct kvm_mmu_page needs to be re-allocated and sp->spt doens't, because it is likely to be mmu->pae_root) The patchset also fixes a possible bug described in: https://lore.kernel.org/lkml/20220415103414.86555-1-jiangshanlai@xxxxxxxxx/ as patch1. And the fixing is simplifed in patch9 with the help of local shadow page. Note: using_local_root_page() can be implemented in two ways. static bool using_local_root_page(struct kvm_mmu *mmu) { return mmu->root_role.level == PT32E_ROOT_LEVEL || (!mmu->root_role.direct && mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL); } static bool using_local_root_page(struct kvm_mmu *mmu) { if (mmu->root_role.direct) return mmu->root_role.level == PT32E_ROOT_LEVEL; else return mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL; } I prefer the second way. But when I wrote the documents for them. I couldn't explain well enough for the second way. Maybe I explained the second way in a wrong aspect or my English is not qualified to explain it. So I put the first way in patch 2 and the second way in patch3. Patch3 adds much more documents and changes the first way to the second way. Patch3 can be discarded. Changed from v2: Add document for using_local_root_page() Update many documents Address review comments Add a patch that fix a possible bug (and split other patches for patch9) Changed from v1: Rebase to newest kvm/queue. Slightly update patch4. [V2]: https://lore.kernel.org/lkml/20220503150735.32723-1-jiangshanlai@xxxxxxxxx/ [V1]: https://lore.kernel.org/lkml/20220420132605.3813-1-jiangshanlai@xxxxxxxxx/ Lai Jiangshan (12): KVM: X86/MMU: Verify PDPTE for nested NPT in PAE paging mode when page fault KVM: X86/MMU: Add using_local_root_page() KVM: X86/MMU: Reduce a check in using_local_root_page() for common cases KVM: X86/MMU: Add local shadow pages KVM: X86/MMU: Link PAE root pagetable with its children KVM: X86/MMU: Activate local shadow pages and remove old logic KVM: X86/MMU: Remove the check of the return value of to_shadow_page() KVM: X86/MMU: Allocate mmu->pae_root for PAE paging on-demand KVM: X86/MMU: Move the verifying of NPT's PDPTE in FNAME(fetch) KVM: X86/MMU: Remove unused INVALID_PAE_ROOT and IS_VALID_PAE_ROOT KVM: X86/MMU: Don't use mmu->pae_root when shadowing PAE NPT in 64-bit host KVM: X86/MMU: Remove mmu_alloc_special_roots() arch/x86/include/asm/kvm_host.h | 5 +- arch/x86/kvm/mmu/mmu.c | 575 ++++++++++++++------------------ arch/x86/kvm/mmu/mmu_internal.h | 10 - arch/x86/kvm/mmu/paging_tmpl.h | 51 ++- arch/x86/kvm/mmu/spte.c | 7 + arch/x86/kvm/mmu/spte.h | 1 + arch/x86/kvm/mmu/tdp_mmu.h | 7 +- arch/x86/kvm/x86.c | 4 +- 8 files changed, 303 insertions(+), 357 deletions(-) -- 2.19.1.6.gb485710b
