On Wed, Dec 03, 2014 at 06:12:10PM +0800, Zhang Haoyu wrote: > > > Hi, > > > > > > EXIT_REASON_EPT_VIOLATION's corresponding handle is handle_ept_violation(), > > > and EXIT_REASON_EPT_MISCONFIG's corresponding handle is handle_ept_misconfig(), > > > what's the difference between them? > > > > > > I read the SDM-3C 28.2.3 EPT-Induced VM Exits, and found below description, > > > "An EPT misconfiguration occurs when, in the course of translating > > > a guest-physical address, the logical processor encounters an EPT > > > paging-structure entry that contains an unsupported value. An EPT > > > violation occurs when there is no EPT misconfiguration but the EPT > > > paging-structure entries disallow an access using the guest physical > > > address." > > > > > > According to above description, EPT-MISCONFIG is from error settings , > > > but from the its exit-handle handle_ept_misconfig(), > > > it seems that handle_ept_misconfig() handles mmio pagefault, > > > I'm really confused, I think I'm missing something, > > > any advices? > > > > > EXIT_REASON_EPT_VIOLATION is similar to a "page not present" pagefault > > EXIT_REASON_EPT_MISCONFIG is similar to a "reserved bit set" pagefault. > > handle_ept_misconfig() handles mmio pagefault because KVM has an > > optimization that uses reserved bits to mark mmio regions. > > > Thanks, Gleb, > where does kvm use the reserved bits to mark mmio regions? > arch/x86/kvm/mmu.c:mark_mmio_spte -- 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
