Until now, we've been setting up KVM using two sets of page tables: one for the "boot" where we perform the basic MMU setup, and one for the runtime. Switching between the two was though to be safe, but we've recently realized that it is not: it is not enough to ensure that the VA->PA mapping is consistent when switching TTBR0_EL2, but we also have to ensure that the intermediate translations are the same as well. If the TLB can return two different values for intermediate translations, we're screwed (TLB conflicts). At that point, the only safe thing to do is to never change TTBR0_EL2, which means that we need to make the idmap page part of the runtime page tables. The series starts with a bit of brain dumping explaining what we're trying to do. This might not be useful as a merge candidate, but it was useful for me to put this somewhere. It goes on revamping the whole notion of HYP VA range, making it runtime patchable. It then always merge idmap and runtime page table into one set, leading to quite a lot of simplification in the init/teardown code. In the process, 32bit KVM gains the ability to teardown the HYP page-tables and vectors, which makes kexec a bit closer. This has been tested on Seattle, Juno, the FVP model (both v8.0 and v8.1), Cubietruck and Midway, and is based on the current kvmarm/queue. Thanks, M. * From v1: - Small changes to documentation patch, thanks to Christoffer - Removed hyp_kern_va altogether - Removed KERN_TO_HYP and used kern_hyp_va everywhere - Rebased on top of kvmarm/queue as of today Marc Zyngier (18): arm64: KVM: Merged page tables documentation arm64: KVM: Always reference __hyp_panic_string via its kernel VA arm/arm64: KVM: Remove hyp_kern_va helper arm64: KVM: Kill HYP_PAGE_OFFSET arm64: Add ARM64_HYP_OFFSET_LOW capability arm64: KVM: Define HYP offset masks arm64: KVM: Refactor kern_hyp_va to deal with multiple offsets arm/arm64: KVM: Export __hyp_text_start/end symbols arm64: KVM: Runtime detection of lower HYP offset arm/arm64: KVM: Always have merged page tables arm64: KVM: Simplify HYP init/teardown arm/arm64: KVM: Drop boot_pgd arm/arm64: KVM: Kill free_boot_hyp_pgd arm: KVM: Simplify HYP init arm: KVM: Allow hyp teardown arm/arm64: KVM: Prune unused #defines arm/arm64: KVM: Check that IDMAP doesn't intersect with VA range arm/arm64: Get rid of KERN_TO_HYP arch/arm/include/asm/kvm_asm.h | 2 + arch/arm/include/asm/kvm_host.h | 25 +++---- arch/arm/include/asm/kvm_hyp.h | 3 - arch/arm/include/asm/kvm_mmu.h | 13 +--- arch/arm/include/asm/virt.h | 4 ++ arch/arm/kvm/arm.c | 20 ++---- arch/arm/kvm/init.S | 56 ++++++--------- arch/arm/kvm/mmu.c | 137 ++++++++++++++++-------------------- arch/arm64/include/asm/cpufeature.h | 3 +- arch/arm64/include/asm/kvm_host.h | 17 ++--- arch/arm64/include/asm/kvm_hyp.h | 23 ------ arch/arm64/include/asm/kvm_mmu.h | 94 ++++++++++++++++++++----- arch/arm64/include/asm/virt.h | 4 ++ arch/arm64/kernel/cpufeature.c | 19 +++++ arch/arm64/kvm/hyp-init.S | 61 +++------------- arch/arm64/kvm/hyp/entry.S | 19 ----- arch/arm64/kvm/hyp/hyp-entry.S | 15 ++++ arch/arm64/kvm/hyp/switch.c | 11 ++- arch/arm64/kvm/reset.c | 28 -------- 19 files changed, 238 insertions(+), 316 deletions(-) -- 2.1.4 -- 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
