On Wed, Oct 09, 2013 at 06:19:52PM +0200, Paolo Bonzini wrote: > Il 09/10/2013 18:13, Gleb Natapov ha scritto: > > 72f857950f6f19 broke shadow on EPT. This patch reverts it and fixes PAE > > on nEPT (which reverted commit fixed) in other way. > > > > Shadow on EPT is now broken because while L1 builds shadow page table > > for L2 (which is PAE while L2 is in real mode) it never loads L2's > > GUEST_PDPTR[0-3]. They do not need to be loaded because without nested > > virtualization HW does this during guest entry if EPT is disabled, > > but in our case L0 emulates L2's vmentry while EPT is enables, so we > > cannot rely on vmcs12->guest_pdptr[0-3] to contain up-to-date values > > and need to re-read PDPTEs from L2 memory. This is what kvm_set_cr3() > > is doing, but by clearing cache bits during L2 vmentry we drop values > > that kvm_set_cr3() read from memory. > > > > So why the same code does not work for PAE on nEPT? kvm_set_cr3() > > reads pdptes into vcpu->arch.walk_mmu->pdptrs[]. walk_mmu points to > > vcpu->arch.nested_mmu while nested guest is running, but ept_load_pdptrs() > > uses vcpu->arch.mmu which contain incorrect values. Fix that by using > > walk_mmu in ept_(load|save)_pdptrs. > > > > Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx> > > The new fix also looks much more obvious. > > Applied to queue, thanks. > The patch that break shadow on EPT is in master IIRC, if it is the case consider this for -rc5. -- Gleb. -- 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
