On Tue, Sep 17, 2019 at 04:52:55PM +0800, Yang, Weijiang wrote: Hi, Paolo, Could you review this v5 patch at your convenience? Thanks a lot! > EPT-Based Sub-Page write Protection(SPP)is a HW capability which allows > Virtual Machine Monitor(VMM) to specify write-permission for guest > physical memory at a sub-page(128 byte) granularity. When this > capability is enabled, the CPU enforces write-access check for sub-pages > within a 4KB page. > > The feature is targeted to provide fine-grained memory protection for > usages such as device virtualization, memory check-point and VM > introspection etc. > > SPP is active when the "sub-page write protection" (bit 23) is 1 in > Secondary VM-Execution Controls. The feature is backed with a Sub-Page > Permission Table(SPPT), SPPT is referenced via a 64-bit control field > called Sub-Page Permission Table Pointer (SPPTP) which contains a > 4K-aligned physical address. > > To enable SPP for certain physical page, the gfn should be first mapped > to a 4KB entry, then set bit 61 of the corresponding EPT leaf entry. > While HW walks EPT, if bit 61 is set, it traverses SPPT with the guset > physical address to find out the sub-page permissions at the leaf entry. > If the corresponding bit is set, write to sub-page is permitted, > otherwise, SPP induced EPT violation is generated. > > This patch serial passed SPP function test and selftest on Ice-Lake platform. > > Please refer to the SPP introduction document in this patch set and > Intel SDM for details: > > Intel SDM: > https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf > > SPP selftest patch: > https://lkml.org/lkml/2019/6/18/1197 > > Previous patch: > https://lkml.org/lkml/2019/8/14/97 > > Patch 1: Introduction to SPP. > Patch 2: Add SPP related flags and control bits. > Patch 3: Functions for SPPT setup. > Patch 4: Add SPP access bitmaps for memslots. > Patch 5: Introduce SPP {init,set,get} functions > Patch 6: Implement User space access IOCTLs. > Patch 7: Set up SPP paging table at vm-entry/exit. > Patch 8: Enable lazy mode SPPT setup. > Patch 9: Handle SPP protected pages when VM memory changes > > > Change logs: > > V5 -> V4: > 1. Enable SPP support for Hugepage(1GB/2MB) to extend application. > 2. Make SPP miss vm-exit handler as the unified place to set up SPPT. > 3. If SPP protected pages are access-tracked or dirty-page-tracked, > store SPP flag in reserved address bit, restore it in > fast_page_fault() handler. > 4. Move SPP specific functions to vmx/spp.c and vmx/spp.h > 5. Rebased code to kernel v5.3 > 6. Other change suggested by KVM community. > > V3 -> V4: > 1. Modified documentation to make it consistent with patches. > 2. Allocated SPPT root page in init_spp() instead of vmx_set_cr3() to > avoid SPPT miss error. > 3. Added back co-developers and sign-offs. > > V2 -> V3: > 1. Rebased patches to kernel 5.1 release > 2. Deferred SPPT setup to EPT fault handler if the page is not > available while set_subpage() is being called. > 3. Added init IOCTL to reduce extra cost if SPP is not used. > 4. Refactored patch structure, cleaned up cross referenced functions. > 5. Added code to deal with memory swapping/migration/shrinker cases. > > V2 -> V1: > 1. Rebased to 4.20-rc1 > 2. Move VMCS change to a separated patch. > 3. Code refine and Bug fix > > > Yang Weijiang (9): > Documentation: Introduce EPT based Subpage Protection > vmx: spp: Add control flags for Sub-Page Protection(SPP) > mmu: spp: Add SPP Table setup functions > mmu: spp: Add functions to create/destroy SPP bitmap block > mmu: spp: Introduce SPP {init,set,get} functions > x86: spp: Introduce user-space SPP IOCTLs > vmx: spp: Set up SPP paging table at vm-entry/exit > mmu: spp: Enable Lazy mode SPP protection > mmu: spp: Handle SPP protected pages when VM memory changes > > Documentation/virtual/kvm/spp_kvm.txt | 178 +++++++ > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/include/asm/kvm_host.h | 10 +- > arch/x86/include/asm/vmx.h | 10 + > arch/x86/include/uapi/asm/vmx.h | 2 + > arch/x86/kernel/cpu/intel.c | 4 + > arch/x86/kvm/mmu.c | 78 ++- > arch/x86/kvm/mmu.h | 2 + > arch/x86/kvm/vmx/capabilities.h | 5 + > arch/x86/kvm/vmx/spp.c | 651 ++++++++++++++++++++++++++ > arch/x86/kvm/vmx/spp.h | 27 ++ > arch/x86/kvm/vmx/vmx.c | 99 ++++ > arch/x86/kvm/x86.c | 51 ++ > include/uapi/linux/kvm.h | 17 + > 14 files changed, 1133 insertions(+), 2 deletions(-) > create mode 100644 Documentation/virtual/kvm/spp_kvm.txt > create mode 100644 arch/x86/kvm/vmx/spp.c > create mode 100644 arch/x86/kvm/vmx/spp.h > > -- > 2.17.2
