On 30/04/2015 12:24, guangrong.xiao@xxxxxxxxxxxxxxx wrote: > From: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> > > This are some MTRR bugs if legacy IOMMU device is used on Intel's CPU: > - In current code, whenever guest MTRR registers are changed > kvm_mmu_reset_context is called to switch to the new root shadow page > table, however, it's useless since: > 1) the cache type is not cached into shadow page's attribute so that the > original root shadow page will be reused > > 2) the cache type is set on the last spte, that means we should sync the > last sptes when MTRR is changed > > We can fix it by dropping all the spte in the gfn range which is > being updated by MTRR > > - some bugs are in get_mtrr_type(); > 1: bit 2 of mtrr_state->enabled is corresponding bit 11 of IA32_MTRR_DEF_TYPE > MSR which completely control MTRR's enablement that means other bits are > ignored if it is cleared > > 2: the fixed MTRR ranges are controlled by bit 1 of mtrr_state->enabled (bit > 10 of IA32_MTRR_DEF_TYPE) > > 3: if MTRR is disabled, UC is applied to all of physical memory rather than > mtrr_state->def_type > > - we need not to reset mmu once cache policy is changed since shadow page table > does not virtualize any cache policy > > Also, these are some cleanups to make current MMU code more cleaner and help > us fixing the bug more easier. > > Xiao Guangrong (9): > KVM: MMU: fix decoding cache type from MTRR > KVM: MMU: introduce slot_handle_level() and its helper > KVM: MMU: use slot_handle_level and its helper to clean up the code > KVM: MMU: introduce for_each_rmap_spte() > KVM: MMU: KVM: introduce for_each_slot_rmap > KVM: MMU: introduce kvm_zap_rmapp > KVM: MMU: introduce kvm_zap_gfn_range() > KVM: MMU: fix MTRR update > KVM: x86: do not reset mmu if CR0.CD and CR0.NW are changed > > arch/x86/include/asm/kvm_host.h | 2 + > arch/x86/kvm/mmu.c | 407 ++++++++++++++++++++++------------------ > arch/x86/kvm/mmu.h | 1 + > arch/x86/kvm/mmu_audit.c | 4 +- > arch/x86/kvm/svm.c | 5 + > arch/x86/kvm/vmx.c | 58 ++++++ > arch/x86/kvm/x86.c | 5 +- > 7 files changed, 294 insertions(+), 188 deletions(-) > Very nice cleanups. I made a couple comments on the patch ordering and the API of iterator macros, but the basic ideas are great. I'm going to apply patch 1, and do some testing with kvm_arch_has_noncoherent_dma forced to return true. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
