On Mon, Sep 9, 2013 at 8:29 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > On Mon, Sep 09, 2013 at 12:53:02PM +0200, Paolo Bonzini wrote: >> Il 09/09/2013 12:22, SPA ha scritto: >> > Thanks Paolo. >> > >> > Is there a way where reads would trap ? >> > >> > I explored a bit on PM_PRESENT_MASK. Though its not READ bit, but a >> > PRESENT bit, it looks like it should generate traps on reads if this >> > bit is reset. From code, looks like rmap_write_protect() like function >> > I stated in previous mail should do. Would this approach work ? Are >> > there any glaring problems with this approach ? >> >> I cannot say right away. Another way could be to set reserved bits to >> generate EPT misconfigurations. See ept_set_mmio_spte_mask and >> is_mmio_spte. >> >> This would trap both reads and writes. >> > Dropping all sptes will also work, but trapping each read access will be dog slow. QEMU > emulation will be much faster. Hi Gleb, I'm interested in this topic, what do you mean by QEMU emulation? Do you mean the functions in arch/x86/kvm/emulate.c? In what scenario will KVM call these functions? Thanks, Arthur > > -- > 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 -- 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
